337 files changed, 1408 insertions, 1323 deletions

diff --git a/changelog.d/8033.misc b/changelog.d/8033.misc
new file mode 100644
index 0000000000..7a9782d14b
--- /dev/null
+++ b/changelog.d/8033.misc
@@ -0,0 +1 @@
+Rename storage layer objects to be more sensible.
diff --git a/docs/user_directory.md b/docs/user_directory.md
index 37dc71e751..872fc21979 100644
--- a/docs/user_directory.md
+++ b/docs/user_directory.md
@@ -7,6 +7,6 @@ who are present in a publicly viewable room present on the server.
 
 The directory info is stored in various tables, which can (typically after
 DB corruption) get stale or out of sync.  If this happens, for now the
-solution to fix it is to execute the SQL [here](../synapse/storage/data_stores/main/schema/delta/53/user_dir_populate.sql)
+solution to fix it is to execute the SQL [here](../synapse/storage/databases/main/schema/delta/53/user_dir_populate.sql)
 and then restart synapse. This should then start a background task to
 flush the current tables and regenerate the directory.
diff --git a/scripts-dev/update_database b/scripts-dev/update_database
index 94aa8758b4..56365e2b58 100755
--- a/scripts-dev/update_database
+++ b/scripts-dev/update_database
@@ -40,7 +40,7 @@ class MockHomeserver(HomeServer):
             config.server_name, reactor=reactor, config=config, **kwargs
         )
 
-        self.version_string = "Synapse/"+get_version_string(synapse)
+        self.version_string = "Synapse/" + get_version_string(synapse)
 
 
 if __name__ == "__main__":
@@ -86,7 +86,7 @@ if __name__ == "__main__":
     store = hs.get_datastore()
 
     async def run_background_updates():
-        await store.db.updates.run_background_updates(sleep=False)
+        await store.db_pool.updates.run_background_updates(sleep=False)
         # Stop the reactor to exit the script once every background update is run.
         reactor.stop()
 
diff --git a/scripts/synapse_port_db b/scripts/synapse_port_db
index bee525197f..ae5e1810fc 100755
--- a/scripts/synapse_port_db
+++ b/scripts/synapse_port_db
@@ -35,31 +35,29 @@ from synapse.logging.context import (
     make_deferred_yieldable,
     run_in_background,
 )
-from synapse.storage.data_stores.main.client_ips import ClientIpBackgroundUpdateStore
-from synapse.storage.data_stores.main.deviceinbox import (
-    DeviceInboxBackgroundUpdateStore,
-)
-from synapse.storage.data_stores.main.devices import DeviceBackgroundUpdateStore
-from synapse.storage.data_stores.main.events_bg_updates import (
+from synapse.storage.database import DatabasePool, make_conn
+from synapse.storage.databases.main.client_ips import ClientIpBackgroundUpdateStore
+from synapse.storage.databases.main.deviceinbox import DeviceInboxBackgroundUpdateStore
+from synapse.storage.databases.main.devices import DeviceBackgroundUpdateStore
+from synapse.storage.databases.main.events_bg_updates import (
     EventsBackgroundUpdatesStore,
 )
-from synapse.storage.data_stores.main.media_repository import (
+from synapse.storage.databases.main.media_repository import (
     MediaRepositoryBackgroundUpdateStore,
 )
-from synapse.storage.data_stores.main.registration import (
+from synapse.storage.databases.main.registration import (
     RegistrationBackgroundUpdateStore,
     find_max_generated_user_id_localpart,
 )
-from synapse.storage.data_stores.main.room import RoomBackgroundUpdateStore
-from synapse.storage.data_stores.main.roommember import RoomMemberBackgroundUpdateStore
-from synapse.storage.data_stores.main.search import SearchBackgroundUpdateStore
-from synapse.storage.data_stores.main.state import MainStateBackgroundUpdateStore
-from synapse.storage.data_stores.main.stats import StatsStore
-from synapse.storage.data_stores.main.user_directory import (
+from synapse.storage.databases.main.room import RoomBackgroundUpdateStore
+from synapse.storage.databases.main.roommember import RoomMemberBackgroundUpdateStore
+from synapse.storage.databases.main.search import SearchBackgroundUpdateStore
+from synapse.storage.databases.main.state import MainStateBackgroundUpdateStore
+from synapse.storage.databases.main.stats import StatsStore
+from synapse.storage.databases.main.user_directory import (
     UserDirectoryBackgroundUpdateStore,
 )
-from synapse.storage.data_stores.state.bg_updates import StateBackgroundUpdateStore
-from synapse.storage.database import Database, make_conn
+from synapse.storage.databases.state.bg_updates import StateBackgroundUpdateStore
 from synapse.storage.engines import create_engine
 from synapse.storage.prepare_database import prepare_database
 from synapse.util import Clock
@@ -175,14 +173,14 @@ class Store(
     StatsStore,
 ):
     def execute(self, f, *args, **kwargs):
-        return self.db.runInteraction(f.__name__, f, *args, **kwargs)
+        return self.db_pool.runInteraction(f.__name__, f, *args, **kwargs)
 
     def execute_sql(self, sql, *args):
         def r(txn):
             txn.execute(sql, args)
             return txn.fetchall()
 
-        return self.db.runInteraction("execute_sql", r)
+        return self.db_pool.runInteraction("execute_sql", r)
 
     def insert_many_txn(self, txn, table, headers, rows):
         sql = "INSERT INTO %s (%s) VALUES (%s)" % (
@@ -227,7 +225,7 @@ class Porter(object):
     async def setup_table(self, table):
         if table in APPEND_ONLY_TABLES:
             # It's safe to just carry on inserting.
-            row = await self.postgres_store.db.simple_select_one(
+            row = await self.postgres_store.db_pool.simple_select_one(
                 table="port_from_sqlite3",
                 keyvalues={"table_name": table},
                 retcols=("forward_rowid", "backward_rowid"),
@@ -244,7 +242,7 @@ class Porter(object):
                     ) = await self._setup_sent_transactions()
                     backward_chunk = 0
                 else:
-                    await self.postgres_store.db.simple_insert(
+                    await self.postgres_store.db_pool.simple_insert(
                         table="port_from_sqlite3",
                         values={
                             "table_name": table,
@@ -274,7 +272,7 @@ class Porter(object):
 
             await self.postgres_store.execute(delete_all)
 
-            await self.postgres_store.db.simple_insert(
+            await self.postgres_store.db_pool.simple_insert(
                 table="port_from_sqlite3",
                 values={"table_name": table, "forward_rowid": 1, "backward_rowid": 0},
             )
@@ -318,7 +316,7 @@ class Porter(object):
         if table == "user_directory_stream_pos":
             # We need to make sure there is a single row, `(X, null), as that is
             # what synapse expects to be there.
-            await self.postgres_store.db.simple_insert(
+            await self.postgres_store.db_pool.simple_insert(
                 table=table, values={"stream_id": None}
             )
             self.progress.update(table, table_size)  # Mark table as done
@@ -359,7 +357,7 @@ class Porter(object):
 
                 return headers, forward_rows, backward_rows
 
-            headers, frows, brows = await self.sqlite_store.db.runInteraction(
+            headers, frows, brows = await self.sqlite_store.db_pool.runInteraction(
                 "select", r
             )
 
@@ -375,7 +373,7 @@ class Porter(object):
                 def insert(txn):
                     self.postgres_store.insert_many_txn(txn, table, headers[1:], rows)
 
-                    self.postgres_store.db.simple_update_one_txn(
+                    self.postgres_store.db_pool.simple_update_one_txn(
                         txn,
                         table="port_from_sqlite3",
                         keyvalues={"table_name": table},
@@ -413,7 +411,7 @@ class Porter(object):
 
                 return headers, rows
 
-            headers, rows = await self.sqlite_store.db.runInteraction("select", r)
+            headers, rows = await self.sqlite_store.db_pool.runInteraction("select", r)
 
             if rows:
                 forward_chunk = rows[-1][0] + 1
@@ -451,7 +449,7 @@ class Porter(object):
                         ],
                     )
 
-                    self.postgres_store.db.simple_update_one_txn(
+                    self.postgres_store.db_pool.simple_update_one_txn(
                         txn,
                         table="port_from_sqlite3",
                         keyvalues={"table_name": "event_search"},
@@ -494,7 +492,7 @@ class Porter(object):
                 db_conn, allow_outdated_version=allow_outdated_version
             )
             prepare_database(db_conn, engine, config=self.hs_config)
-            store = Store(Database(hs, db_config, engine), db_conn, hs)
+            store = Store(DatabasePool(hs, db_config, engine), db_conn, hs)
             db_conn.commit()
 
         return store
@@ -502,7 +500,7 @@ class Porter(object):
     async def run_background_updates_on_postgres(self):
         # Manually apply all background updates on the PostgreSQL database.
         postgres_ready = (
-            await self.postgres_store.db.updates.has_completed_background_updates()
+            await self.postgres_store.db_pool.updates.has_completed_background_updates()
         )
 
         if not postgres_ready:
@@ -511,9 +509,9 @@ class Porter(object):
             self.progress.set_state("Running background updates on PostgreSQL")
 
         while not postgres_ready:
-            await self.postgres_store.db.updates.do_next_background_update(100)
+            await self.postgres_store.db_pool.updates.do_next_background_update(100)
             postgres_ready = await (
-                self.postgres_store.db.updates.has_completed_background_updates()
+                self.postgres_store.db_pool.updates.has_completed_background_updates()
             )
 
     async def run(self):
@@ -534,7 +532,7 @@ class Porter(object):
 
             # Check if all background updates are done, abort if not.
             updates_complete = (
-                await self.sqlite_store.db.updates.has_completed_background_updates()
+                await self.sqlite_store.db_pool.updates.has_completed_background_updates()
             )
             if not updates_complete:
                 end_error = (
@@ -576,22 +574,24 @@ class Porter(object):
                 )
 
             try:
-                await self.postgres_store.db.runInteraction("alter_table", alter_table)
+                await self.postgres_store.db_pool.runInteraction(
+                    "alter_table", alter_table
+                )
             except Exception:
                 # On Error Resume Next
                 pass
 
-            await self.postgres_store.db.runInteraction(
+            await self.postgres_store.db_pool.runInteraction(
                 "create_port_table", create_port_table
             )
 
             # Step 2. Get tables.
             self.progress.set_state("Fetching tables")
-            sqlite_tables = await self.sqlite_store.db.simple_select_onecol(
+            sqlite_tables = await self.sqlite_store.db_pool.simple_select_onecol(
                 table="sqlite_master", keyvalues={"type": "table"}, retcol="name"
             )
 
-            postgres_tables = await self.postgres_store.db.simple_select_onecol(
+            postgres_tables = await self.postgres_store.db_pool.simple_select_onecol(
                 table="information_schema.tables",
                 keyvalues={},
                 retcol="distinct table_name",
@@ -692,7 +692,7 @@ class Porter(object):
 
             return headers, [r for r in rows if r[ts_ind] < yesterday]
 
-        headers, rows = await self.sqlite_store.db.runInteraction("select", r)
+        headers, rows = await self.sqlite_store.db_pool.runInteraction("select", r)
 
         rows = self._convert_rows("sent_transactions", headers, rows)
 
@@ -725,7 +725,7 @@ class Porter(object):
         next_chunk = await self.sqlite_store.execute(get_start_id)
         next_chunk = max(max_inserted_rowid + 1, next_chunk)
 
-        await self.postgres_store.db.simple_insert(
+        await self.postgres_store.db_pool.simple_insert(
             table="port_from_sqlite3",
             values={
                 "table_name": "sent_transactions",
@@ -794,14 +794,14 @@ class Porter(object):
             next_id = curr_id + 1
             txn.execute("ALTER SEQUENCE state_group_id_seq RESTART WITH %s", (next_id,))
 
-        return self.postgres_store.db.runInteraction("setup_state_group_id_seq", r)
+        return self.postgres_store.db_pool.runInteraction("setup_state_group_id_seq", r)
 
     def _setup_user_id_seq(self):
         def r(txn):
             next_id = find_max_generated_user_id_localpart(txn) + 1
             txn.execute("ALTER SEQUENCE user_id_seq RESTART WITH %s", (next_id,))
 
-        return self.postgres_store.db.runInteraction("setup_user_id_seq", r)
+        return self.postgres_store.db_pool.runInteraction("setup_user_id_seq", r)
 
 
 ##############################################
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index fa40c68f53..2b2cd795e0 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -268,7 +268,7 @@ def start(hs: "synapse.server.HomeServer", listeners: Iterable[ListenerConfig]):
 
         # It is now safe to start your Synapse.
         hs.start_listening(listeners)
-        hs.get_datastore().db.start_profiling()
+        hs.get_datastore().db_pool.start_profiling()
         hs.get_pusherpool().start()
 
         setup_sentry(hs)
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
index c478df53be..1a16d0b9f8 100644
--- a/synapse/app/generic_worker.py
+++ b/synapse/app/generic_worker.py
@@ -125,15 +125,15 @@ from synapse.rest.client.v2_alpha.register import RegisterRestServlet
 from synapse.rest.client.versions import VersionsRestServlet
 from synapse.rest.key.v2 import KeyApiV2Resource
 from synapse.server import HomeServer
-from synapse.storage.data_stores.main.censor_events import CensorEventsStore
-from synapse.storage.data_stores.main.media_repository import MediaRepositoryStore
-from synapse.storage.data_stores.main.monthly_active_users import (
+from synapse.storage.databases.main.censor_events import CensorEventsStore
+from synapse.storage.databases.main.media_repository import MediaRepositoryStore
+from synapse.storage.databases.main.monthly_active_users import (
     MonthlyActiveUsersWorkerStore,
 )
-from synapse.storage.data_stores.main.presence import UserPresenceState
-from synapse.storage.data_stores.main.search import SearchWorkerStore
-from synapse.storage.data_stores.main.ui_auth import UIAuthWorkerStore
-from synapse.storage.data_stores.main.user_directory import UserDirectoryStore
+from synapse.storage.databases.main.presence import UserPresenceState
+from synapse.storage.databases.main.search import SearchWorkerStore
+from synapse.storage.databases.main.ui_auth import UIAuthWorkerStore
+from synapse.storage.databases.main.user_directory import UserDirectoryStore
 from synapse.types import ReadReceipt
 from synapse.util.async_helpers import Linearizer
 from synapse.util.httpresourcetree import create_resource_tree
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index b011e00b4b..d87a77718e 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -441,7 +441,7 @@ def setup(config_options):
 
             _base.start(hs, config.listeners)
 
-            hs.get_datastore().db.updates.start_doing_background_updates()
+            hs.get_datastore().db_pool.updates.start_doing_background_updates()
         except Exception:
             # Print the exception and bail out.
             print("Error during startup:", file=sys.stderr)
@@ -551,8 +551,8 @@ async def phone_stats_home(hs, stats, stats_process=_stats_process):
     #
 
     # This only reports info about the *main* database.
-    stats["database_engine"] = hs.get_datastore().db.engine.module.__name__
-    stats["database_server_version"] = hs.get_datastore().db.engine.server_version
+    stats["database_engine"] = hs.get_datastore().db_pool.engine.module.__name__
+    stats["database_server_version"] = hs.get_datastore().db_pool.engine.server_version
 
     logger.info("Reporting stats to %s: %s" % (hs.config.report_stats_endpoint, stats))
     try:
diff --git a/synapse/config/database.py b/synapse/config/database.py
index 62bccd9ef5..8a18a9ca2a 100644
--- a/synapse/config/database.py
+++ b/synapse/config/database.py
@@ -100,7 +100,10 @@ class DatabaseConnectionConfig:
 
         self.name = name
         self.config = db_config
-        self.data_stores = data_stores
+
+        # The `data_stores` config is actually talking about `databases` (we
+        # changed the name).
+        self.databases = data_stores
 
 
 class DatabaseConfig(Config):
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index cca93e3a46..afecafe15c 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -23,7 +23,7 @@ from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.types import StateMap
 
 if TYPE_CHECKING:
-    from synapse.storage.data_stores.main import DataStore
+    from synapse.storage.databases.main import DataStore
 
 
 @attr.s(slots=True)
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 0d7d1adcea..b3764dedae 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -71,7 +71,7 @@ from synapse.replication.http.federation import (
 )
 from synapse.replication.http.membership import ReplicationUserJoinedLeftRoomRestServlet
 from synapse.state import StateResolutionStore, resolve_events_with_store
-from synapse.storage.data_stores.main.events_worker import EventRedactBehaviour
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.types import JsonDict, StateMap, UserID, get_domain_from_id
 from synapse.util.async_helpers import Linearizer, concurrently_execute
 from synapse.util.distributor import user_joined_room
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index e451d6dc86..43901d0934 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -45,7 +45,7 @@ from synapse.events.validator import EventValidator
 from synapse.logging.context import run_in_background
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.replication.http.send_event import ReplicationSendEventRestServlet
-from synapse.storage.data_stores.main.events_worker import EventRedactBehaviour
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.state import StateFilter
 from synapse.types import (
     Collection,
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index b3a3bb8c3f..5387b3724f 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -38,7 +38,7 @@ from synapse.logging.utils import log_function
 from synapse.metrics import LaterGauge
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.state import StateHandler
-from synapse.storage.data_stores.main import DataStore
+from synapse.storage.databases.main import DataStore
 from synapse.storage.presence import UserPresenceState
 from synapse.types import JsonDict, UserID, get_domain_from_id
 from synapse.util.async_helpers import Linearizer
@@ -319,7 +319,7 @@ class PresenceHandler(BasePresenceHandler):
         is some spurious presence changes that will self-correct.
         """
         # If the DB pool has already terminated, don't try updating
-        if not self.store.db.is_running():
+        if not self.store.db_pool.is_running():
             return
 
         logger.info(
diff --git a/synapse/module_api/__init__.py b/synapse/module_api/__init__.py
index a7849cefa5..8201849951 100644
--- a/synapse/module_api/__init__.py
+++ b/synapse/module_api/__init__.py
@@ -219,7 +219,7 @@ class ModuleApi(object):
         Returns:
             Deferred[object]: result of func
         """
-        return self._store.db.runInteraction(desc, func, *args, **kwargs)
+        return self._store.db_pool.runInteraction(desc, func, *args, **kwargs)
 
     def complete_sso_login(
         self, registered_user_id: str, request: SynapseRequest, client_redirect_url: str
diff --git a/synapse/replication/slave/storage/_base.py b/synapse/replication/slave/storage/_base.py
index f9e2533e96..60f2e1245f 100644
--- a/synapse/replication/slave/storage/_base.py
+++ b/synapse/replication/slave/storage/_base.py
@@ -16,8 +16,8 @@
 import logging
 from typing import Optional
 
-from synapse.storage.data_stores.main.cache import CacheInvalidationWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.cache import CacheInvalidationWorkerStore
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.util.id_generators import MultiWriterIdGenerator
 
@@ -25,7 +25,7 @@ logger = logging.getLogger(__name__)
 
 
 class BaseSlavedStore(CacheInvalidationWorkerStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(BaseSlavedStore, self).__init__(database, db_conn, hs)
         if isinstance(self.database_engine, PostgresEngine):
             self._cache_id_gen = MultiWriterIdGenerator(
diff --git a/synapse/replication/slave/storage/account_data.py b/synapse/replication/slave/storage/account_data.py
index 525b94fd87..154f0e687c 100644
--- a/synapse/replication/slave/storage/account_data.py
+++ b/synapse/replication/slave/storage/account_data.py
@@ -17,13 +17,13 @@
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.replication.tcp.streams import AccountDataStream, TagAccountDataStream
-from synapse.storage.data_stores.main.account_data import AccountDataWorkerStore
-from synapse.storage.data_stores.main.tags import TagsWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.account_data import AccountDataWorkerStore
+from synapse.storage.databases.main.tags import TagsWorkerStore
 
 
 class SlavedAccountDataStore(TagsWorkerStore, AccountDataWorkerStore, BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         self._account_data_id_gen = SlavedIdTracker(
             db_conn,
             "account_data",
diff --git a/synapse/replication/slave/storage/appservice.py b/synapse/replication/slave/storage/appservice.py
index a67fbeffb7..0f8d7037bd 100644
--- a/synapse/replication/slave/storage/appservice.py
+++ b/synapse/replication/slave/storage/appservice.py
@@ -14,7 +14,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.main.appservice import (
+from synapse.storage.databases.main.appservice import (
     ApplicationServiceTransactionWorkerStore,
     ApplicationServiceWorkerStore,
 )
diff --git a/synapse/replication/slave/storage/client_ips.py b/synapse/replication/slave/storage/client_ips.py
index 1a38f53dfb..60dd3f6701 100644
--- a/synapse/replication/slave/storage/client_ips.py
+++ b/synapse/replication/slave/storage/client_ips.py
@@ -13,15 +13,15 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.main.client_ips import LAST_SEEN_GRANULARITY
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.client_ips import LAST_SEEN_GRANULARITY
 from synapse.util.caches.descriptors import Cache
 
 from ._base import BaseSlavedStore
 
 
 class SlavedClientIpStore(BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedClientIpStore, self).__init__(database, db_conn, hs)
 
         self.client_ip_last_seen = Cache(
diff --git a/synapse/replication/slave/storage/deviceinbox.py b/synapse/replication/slave/storage/deviceinbox.py
index a8a16dbc71..ee7f69a918 100644
--- a/synapse/replication/slave/storage/deviceinbox.py
+++ b/synapse/replication/slave/storage/deviceinbox.py
@@ -16,14 +16,14 @@
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.replication.tcp.streams import ToDeviceStream
-from synapse.storage.data_stores.main.deviceinbox import DeviceInboxWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.deviceinbox import DeviceInboxWorkerStore
 from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 
 class SlavedDeviceInboxStore(DeviceInboxWorkerStore, BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedDeviceInboxStore, self).__init__(database, db_conn, hs)
         self._device_inbox_id_gen = SlavedIdTracker(
             db_conn, "device_inbox", "stream_id"
diff --git a/synapse/replication/slave/storage/devices.py b/synapse/replication/slave/storage/devices.py
index 9d8067342f..722f3745e9 100644
--- a/synapse/replication/slave/storage/devices.py
+++ b/synapse/replication/slave/storage/devices.py
@@ -16,14 +16,14 @@
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.replication.tcp.streams._base import DeviceListsStream, UserSignatureStream
-from synapse.storage.data_stores.main.devices import DeviceWorkerStore
-from synapse.storage.data_stores.main.end_to_end_keys import EndToEndKeyWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.devices import DeviceWorkerStore
+from synapse.storage.databases.main.end_to_end_keys import EndToEndKeyWorkerStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 
 class SlavedDeviceStore(EndToEndKeyWorkerStore, DeviceWorkerStore, BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedDeviceStore, self).__init__(database, db_conn, hs)
 
         self.hs = hs
diff --git a/synapse/replication/slave/storage/directory.py b/synapse/replication/slave/storage/directory.py
index 8b9717c46f..1945bcf9a8 100644
--- a/synapse/replication/slave/storage/directory.py
+++ b/synapse/replication/slave/storage/directory.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.main.directory import DirectoryWorkerStore
+from synapse.storage.databases.main.directory import DirectoryWorkerStore
 
 from ._base import BaseSlavedStore
 
diff --git a/synapse/replication/slave/storage/events.py b/synapse/replication/slave/storage/events.py
index 1a1a50a24f..da1cc836cf 100644
--- a/synapse/replication/slave/storage/events.py
+++ b/synapse/replication/slave/storage/events.py
@@ -15,18 +15,18 @@
 # limitations under the License.
 import logging
 
-from synapse.storage.data_stores.main.event_federation import EventFederationWorkerStore
-from synapse.storage.data_stores.main.event_push_actions import (
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.event_federation import EventFederationWorkerStore
+from synapse.storage.databases.main.event_push_actions import (
     EventPushActionsWorkerStore,
 )
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.data_stores.main.relations import RelationsWorkerStore
-from synapse.storage.data_stores.main.roommember import RoomMemberWorkerStore
-from synapse.storage.data_stores.main.signatures import SignatureWorkerStore
-from synapse.storage.data_stores.main.state import StateGroupWorkerStore
-from synapse.storage.data_stores.main.stream import StreamWorkerStore
-from synapse.storage.data_stores.main.user_erasure_store import UserErasureWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
+from synapse.storage.databases.main.relations import RelationsWorkerStore
+from synapse.storage.databases.main.roommember import RoomMemberWorkerStore
+from synapse.storage.databases.main.signatures import SignatureWorkerStore
+from synapse.storage.databases.main.state import StateGroupWorkerStore
+from synapse.storage.databases.main.stream import StreamWorkerStore
+from synapse.storage.databases.main.user_erasure_store import UserErasureWorkerStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 from ._base import BaseSlavedStore
@@ -55,11 +55,11 @@ class SlavedEventStore(
     RelationsWorkerStore,
     BaseSlavedStore,
 ):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedEventStore, self).__init__(database, db_conn, hs)
 
         events_max = self._stream_id_gen.get_current_token()
-        curr_state_delta_prefill, min_curr_state_delta_id = self.db.get_cache_dict(
+        curr_state_delta_prefill, min_curr_state_delta_id = self.db_pool.get_cache_dict(
             db_conn,
             "current_state_delta_stream",
             entity_column="room_id",
diff --git a/synapse/replication/slave/storage/filtering.py b/synapse/replication/slave/storage/filtering.py
index bcb0688954..2562b6fc38 100644
--- a/synapse/replication/slave/storage/filtering.py
+++ b/synapse/replication/slave/storage/filtering.py
@@ -13,14 +13,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.main.filtering import FilteringStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.filtering import FilteringStore
 
 from ._base import BaseSlavedStore
 
 
 class SlavedFilteringStore(BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedFilteringStore, self).__init__(database, db_conn, hs)
 
     # Filters are immutable so this cache doesn't need to be expired
diff --git a/synapse/replication/slave/storage/groups.py b/synapse/replication/slave/storage/groups.py
index 5d210fa3a1..3291558c7a 100644
--- a/synapse/replication/slave/storage/groups.py
+++ b/synapse/replication/slave/storage/groups.py
@@ -16,13 +16,13 @@
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.replication.tcp.streams import GroupServerStream
-from synapse.storage.data_stores.main.group_server import GroupServerWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.group_server import GroupServerWorkerStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 
 class SlavedGroupServerStore(GroupServerWorkerStore, BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedGroupServerStore, self).__init__(database, db_conn, hs)
 
         self.hs = hs
diff --git a/synapse/replication/slave/storage/keys.py b/synapse/replication/slave/storage/keys.py
index 3def367ae9..961579751c 100644
--- a/synapse/replication/slave/storage/keys.py
+++ b/synapse/replication/slave/storage/keys.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.main.keys import KeyStore
+from synapse.storage.databases.main.keys import KeyStore
 
 # KeyStore isn't really safe to use from a worker, but for now we do so and hope that
 # the races it creates aren't too bad.
diff --git a/synapse/replication/slave/storage/presence.py b/synapse/replication/slave/storage/presence.py
index 2938cb8e43..a912c04360 100644
--- a/synapse/replication/slave/storage/presence.py
+++ b/synapse/replication/slave/storage/presence.py
@@ -15,8 +15,8 @@
 
 from synapse.replication.tcp.streams import PresenceStream
 from synapse.storage import DataStore
-from synapse.storage.data_stores.main.presence import PresenceStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.presence import PresenceStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
 
 from ._base import BaseSlavedStore
@@ -24,7 +24,7 @@ from ._slaved_id_tracker import SlavedIdTracker
 
 
 class SlavedPresenceStore(BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedPresenceStore, self).__init__(database, db_conn, hs)
         self._presence_id_gen = SlavedIdTracker(db_conn, "presence_stream", "stream_id")
 
diff --git a/synapse/replication/slave/storage/profile.py b/synapse/replication/slave/storage/profile.py
index 28c508aad3..f85b20a071 100644
--- a/synapse/replication/slave/storage/profile.py
+++ b/synapse/replication/slave/storage/profile.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 from synapse.replication.slave.storage._base import BaseSlavedStore
-from synapse.storage.data_stores.main.profile import ProfileWorkerStore
+from synapse.storage.databases.main.profile import ProfileWorkerStore
 
 
 class SlavedProfileStore(ProfileWorkerStore, BaseSlavedStore):
diff --git a/synapse/replication/slave/storage/push_rule.py b/synapse/replication/slave/storage/push_rule.py
index 23ec1c5b11..590187df46 100644
--- a/synapse/replication/slave/storage/push_rule.py
+++ b/synapse/replication/slave/storage/push_rule.py
@@ -15,7 +15,7 @@
 # limitations under the License.
 
 from synapse.replication.tcp.streams import PushRulesStream
-from synapse.storage.data_stores.main.push_rule import PushRulesWorkerStore
+from synapse.storage.databases.main.push_rule import PushRulesWorkerStore
 
 from .events import SlavedEventStore
 
diff --git a/synapse/replication/slave/storage/pushers.py b/synapse/replication/slave/storage/pushers.py
index ff449f3658..63300e5da6 100644
--- a/synapse/replication/slave/storage/pushers.py
+++ b/synapse/replication/slave/storage/pushers.py
@@ -15,15 +15,15 @@
 # limitations under the License.
 
 from synapse.replication.tcp.streams import PushersStream
-from synapse.storage.data_stores.main.pusher import PusherWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.pusher import PusherWorkerStore
 
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
 
 class SlavedPusherStore(PusherWorkerStore, BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SlavedPusherStore, self).__init__(database, db_conn, hs)
         self._pushers_id_gen = SlavedIdTracker(
             db_conn, "pushers", "id", extra_tables=[("deleted_pushers", "stream_id")]
diff --git a/synapse/replication/slave/storage/receipts.py b/synapse/replication/slave/storage/receipts.py
index 6982686eb5..17ba1f22ac 100644
--- a/synapse/replication/slave/storage/receipts.py
+++ b/synapse/replication/slave/storage/receipts.py
@@ -15,15 +15,15 @@
 # limitations under the License.
 
 from synapse.replication.tcp.streams import ReceiptsStream
-from synapse.storage.data_stores.main.receipts import ReceiptsWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.receipts import ReceiptsWorkerStore
 
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
 
 class SlavedReceiptsStore(ReceiptsWorkerStore, BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         # We instantiate this first as the ReceiptsWorkerStore constructor
         # needs to be able to call get_max_receipt_stream_id
         self._receipts_id_gen = SlavedIdTracker(
diff --git a/synapse/replication/slave/storage/registration.py b/synapse/replication/slave/storage/registration.py
index 4b8553e250..a40f064e2b 100644
--- a/synapse/replication/slave/storage/registration.py
+++ b/synapse/replication/slave/storage/registration.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.main.registration import RegistrationWorkerStore
+from synapse.storage.databases.main.registration import RegistrationWorkerStore
 
 from ._base import BaseSlavedStore
 
diff --git a/synapse/replication/slave/storage/room.py b/synapse/replication/slave/storage/room.py
index 8710207ada..427c81772b 100644
--- a/synapse/replication/slave/storage/room.py
+++ b/synapse/replication/slave/storage/room.py
@@ -14,15 +14,15 @@
 # limitations under the License.
 
 from synapse.replication.tcp.streams import PublicRoomsStream
-from synapse.storage.data_stores.main.room import RoomWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.room import RoomWorkerStore
 
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
 
 
 class RoomStore(RoomWorkerStore, BaseSlavedStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RoomStore, self).__init__(database, db_conn, hs)
         self._public_room_id_gen = SlavedIdTracker(
             db_conn, "public_room_list_stream", "stream_id"
diff --git a/synapse/replication/slave/storage/transactions.py b/synapse/replication/slave/storage/transactions.py
index ac88e6b8c3..2091ac0df6 100644
--- a/synapse/replication/slave/storage/transactions.py
+++ b/synapse/replication/slave/storage/transactions.py
@@ -13,7 +13,7 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.main.transactions import TransactionStore
+from synapse.storage.databases.main.transactions import TransactionStore
 
 from ._base import BaseSlavedStore
 
diff --git a/synapse/rest/admin/rooms.py b/synapse/rest/admin/rooms.py
index a8364d9793..7c292ef3f9 100644
--- a/synapse/rest/admin/rooms.py
+++ b/synapse/rest/admin/rooms.py
@@ -31,7 +31,7 @@ from synapse.rest.admin._base import (
     assert_user_is_admin,
     historical_admin_path_patterns,
 )
-from synapse.storage.data_stores.main.room import RoomSortOrder
+from synapse.storage.databases.main.room import RoomSortOrder
 from synapse.types import RoomAlias, RoomID, UserID, create_requester
 
 logger = logging.getLogger(__name__)
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index e12f65a206..f4768a9e8b 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -586,7 +586,7 @@ class PreviewUrlResource(DirectServeJsonResource):
 
         logger.debug("Running url preview cache expiry")
 
-        if not (await self.store.db.updates.has_completed_background_updates()):
+        if not (await self.store.db_pool.updates.has_completed_background_updates()):
             logger.info("Still running DB updates; skipping expiry")
             return
 
diff --git a/synapse/server.py b/synapse/server.py
index 8e41112530..81d7f26f9c 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -105,7 +105,7 @@ from synapse.server_notices.worker_server_notices_sender import (
     WorkerServerNoticesSender,
 )
 from synapse.state import StateHandler, StateResolutionHandler
-from synapse.storage import DataStore, DataStores, Storage
+from synapse.storage import Databases, DataStore, Storage
 from synapse.streams.events import EventSources
 from synapse.util import Clock
 from synapse.util.distributor import Distributor
@@ -280,7 +280,7 @@ class HomeServer(object):
     def setup(self):
         logger.info("Setting up.")
         self.start_time = int(self.get_clock().time())
-        self.datastores = DataStores(self.DATASTORE_CLASS, self)
+        self.datastores = Databases(self.DATASTORE_CLASS, self)
         logger.info("Finished setting up.")
 
     def setup_master(self):
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index 25ccef5aa5..a1d3884667 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -28,7 +28,7 @@ from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.logging.utils import log_function
 from synapse.state import v1, v2
-from synapse.storage.data_stores.main.events_worker import EventRedactBehaviour
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.roommember import ProfileInfo
 from synapse.types import StateMap
 from synapse.util import Clock
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index ec89f645d4..5ef3853559 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -17,18 +17,19 @@
 """
 The storage layer is split up into multiple parts to allow Synapse to run
 against different configurations of databases (e.g. single or multiple
-databases). The `Database` class represents a single physical database. The
-`data_stores` are classes that talk directly to a `Database` instance and have
-associated schemas, background updates, etc. On top of those there are classes
-that provide high level interfaces that combine calls to multiple `data_stores`.
+databases). The `DatabasePool` class represents connections to a single physical
+database. The `databases` are classes that talk directly to a `DatabasePool`
+instance and have associated schemas, background updates, etc. On top of those
+there are classes that provide high level interfaces that combine calls to
+multiple `databases`.
 
 There are also schemas that get applied to every database, regardless of the
 data stores associated with them (e.g. the schema version tables), which are
 stored in `synapse.storage.schema`.
 """
 
-from synapse.storage.data_stores import DataStores
-from synapse.storage.data_stores.main import DataStore
+from synapse.storage.databases import Databases
+from synapse.storage.databases.main import DataStore
 from synapse.storage.persist_events import EventsPersistenceStorage
 from synapse.storage.purge_events import PurgeEventsStorage
 from synapse.storage.state import StateGroupStorage
@@ -40,7 +41,7 @@ class Storage(object):
     """The high level interfaces for talking to various storage layers.
     """
 
-    def __init__(self, hs, stores: DataStores):
+    def __init__(self, hs, stores: Databases):
         # We include the main data store here mainly so that we don't have to
         # rewrite all the existing code to split it into high vs low level
         # interfaces.
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index 985a042869..ca800df831 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -23,7 +23,7 @@ from canonicaljson import json
 
 from synapse.storage.database import LoggingTransaction  # noqa: F401
 from synapse.storage.database import make_in_list_sql_clause  # noqa: F401
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.types import Collection, get_domain_from_id
 
 logger = logging.getLogger(__name__)
@@ -37,11 +37,11 @@ class SQLBaseStore(metaclass=ABCMeta):
     per data store (and not one per physical database).
     """
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         self.hs = hs
         self._clock = hs.get_clock()
         self.database_engine = database.engine
-        self.db = database
+        self.db_pool = database
         self.rand = random.SystemRandom()
 
     def process_replication_rows(self, stream_name, instance_name, token, rows):
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
index 018826ef69..f43463df53 100644
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@@ -88,7 +88,7 @@ class BackgroundUpdater(object):
 
     def __init__(self, hs, database):
         self._clock = hs.get_clock()
-        self.db = database
+        self.db_pool = database
 
         # if a background update is currently running, its name.
         self._current_background_update = None  # type: Optional[str]
@@ -139,7 +139,7 @@ class BackgroundUpdater(object):
         # otherwise, check if there are updates to be run. This is important,
         # as we may be running on a worker which doesn't perform the bg updates
         # itself, but still wants to wait for them to happen.
-        updates = await self.db.simple_select_onecol(
+        updates = await self.db_pool.simple_select_onecol(
             "background_updates",
             keyvalues=None,
             retcol="1",
@@ -160,7 +160,7 @@ class BackgroundUpdater(object):
         if update_name == self._current_background_update:
             return False
 
-        update_exists = await self.db.simple_select_one_onecol(
+        update_exists = await self.db_pool.simple_select_one_onecol(
             "background_updates",
             keyvalues={"update_name": update_name},
             retcol="1",
@@ -189,10 +189,10 @@ class BackgroundUpdater(object):
                 ORDER BY ordering, update_name
                 """
             )
-            return self.db.cursor_to_dict(txn)
+            return self.db_pool.cursor_to_dict(txn)
 
         if not self._current_background_update:
-            all_pending_updates = await self.db.runInteraction(
+            all_pending_updates = await self.db_pool.runInteraction(
                 "background_updates", get_background_updates_txn,
             )
             if not all_pending_updates:
@@ -243,7 +243,7 @@ class BackgroundUpdater(object):
         else:
             batch_size = self.DEFAULT_BACKGROUND_BATCH_SIZE
 
-        progress_json = await self.db.simple_select_one_onecol(
+        progress_json = await self.db_pool.simple_select_one_onecol(
             "background_updates",
             keyvalues={"update_name": update_name},
             retcol="progress_json",
@@ -402,7 +402,7 @@ class BackgroundUpdater(object):
             logger.debug("[SQL] %s", sql)
             c.execute(sql)
 
-        if isinstance(self.db.engine, engines.PostgresEngine):
+        if isinstance(self.db_pool.engine, engines.PostgresEngine):
             runner = create_index_psql
         elif psql_only:
             runner = None
@@ -413,7 +413,7 @@ class BackgroundUpdater(object):
         def updater(progress, batch_size):
             if runner is not None:
                 logger.info("Adding index %s to %s", index_name, table)
-                yield self.db.runWithConnection(runner)
+                yield self.db_pool.runWithConnection(runner)
             yield self._end_background_update(update_name)
             return 1
 
@@ -433,7 +433,7 @@ class BackgroundUpdater(object):
                 % update_name
             )
         self._current_background_update = None
-        return self.db.simple_delete_one(
+        return self.db_pool.simple_delete_one(
             "background_updates", keyvalues={"update_name": update_name}
         )
 
@@ -445,7 +445,7 @@ class BackgroundUpdater(object):
             progress: The progress of the update.
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "background_update_progress",
             self._background_update_progress_txn,
             update_name,
@@ -463,7 +463,7 @@ class BackgroundUpdater(object):
 
         progress_json = json.dumps(progress)
 
-        self.db.simple_update_one_txn(
+        self.db_pool.simple_update_one_txn(
             txn,
             "background_updates",
             keyvalues={"update_name": update_name},
diff --git a/synapse/storage/database.py b/synapse/storage/database.py
index ce8757a400..4ada6f5563 100644
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@@ -279,7 +279,7 @@ class PerformanceCounters(object):
         return top_n_counters
 
 
-class Database(object):
+class DatabasePool(object):
     """Wraps a single physical database and connection pool.
 
     A single database may be used by multiple data stores.
diff --git a/synapse/storage/data_stores/__init__.py b/synapse/storage/databases/__init__.py
index 599ee470d4..b163eebf39 100644
--- a/synapse/storage/data_stores/__init__.py
+++ b/synapse/storage/databases/__init__.py
@@ -15,17 +15,17 @@
 
 import logging
 
-from synapse.storage.data_stores.main.events import PersistEventsStore
-from synapse.storage.data_stores.state import StateGroupDataStore
-from synapse.storage.database import Database, make_conn
+from synapse.storage.database import DatabasePool, make_conn
+from synapse.storage.databases.main.events import PersistEventsStore
+from synapse.storage.databases.state import StateGroupDataStore
 from synapse.storage.engines import create_engine
 from synapse.storage.prepare_database import prepare_database
 
 logger = logging.getLogger(__name__)
 
 
-class DataStores(object):
-    """The various data stores.
+class Databases(object):
+    """The various databases.
 
     These are low level interfaces to physical databases.
 
@@ -51,12 +51,12 @@ class DataStores(object):
 
                 engine.check_database(db_conn)
                 prepare_database(
-                    db_conn, engine, hs.config, data_stores=database_config.data_stores,
+                    db_conn, engine, hs.config, databases=database_config.databases,
                 )
 
-                database = Database(hs, database_config, engine)
+                database = DatabasePool(hs, database_config, engine)
 
-                if "main" in database_config.data_stores:
+                if "main" in database_config.databases:
                     logger.info("Starting 'main' data store")
 
                     # Sanity check we don't try and configure the main store on
@@ -73,7 +73,7 @@ class DataStores(object):
                             hs, database, self.main
                         )
 
-                if "state" in database_config.data_stores:
+                if "state" in database_config.databases:
                     logger.info("Starting 'state' data store")
 
                     # Sanity check we don't try and configure the state store on
diff --git a/synapse/storage/data_stores/main/__init__.py b/synapse/storage/databases/main/__init__.py
index 932458f651..17fa470919 100644
--- a/synapse/storage/data_stores/main/__init__.py
+++ b/synapse/storage/databases/main/__init__.py
@@ -21,7 +21,7 @@ import time
 
 from synapse.api.constants import PresenceState
 from synapse.config.homeserver import HomeServerConfig
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.util.id_generators import (
     IdGenerator,
@@ -119,7 +119,7 @@ class DataStore(
     CacheInvalidationWorkerStore,
     ServerMetricsStore,
 ):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         self.hs = hs
         self._clock = hs.get_clock()
         self.database_engine = database.engine
@@ -174,7 +174,7 @@ class DataStore(
 
         self._presence_on_startup = self._get_active_presence(db_conn)
 
-        presence_cache_prefill, min_presence_val = self.db.get_cache_dict(
+        presence_cache_prefill, min_presence_val = self.db_pool.get_cache_dict(
             db_conn,
             "presence_stream",
             entity_column="user_id",
@@ -188,7 +188,7 @@ class DataStore(
         )
 
         max_device_inbox_id = self._device_inbox_id_gen.get_current_token()
-        device_inbox_prefill, min_device_inbox_id = self.db.get_cache_dict(
+        device_inbox_prefill, min_device_inbox_id = self.db_pool.get_cache_dict(
             db_conn,
             "device_inbox",
             entity_column="user_id",
@@ -203,7 +203,7 @@ class DataStore(
         )
         # The federation outbox and the local device inbox uses the same
         # stream_id generator.
-        device_outbox_prefill, min_device_outbox_id = self.db.get_cache_dict(
+        device_outbox_prefill, min_device_outbox_id = self.db_pool.get_cache_dict(
             db_conn,
             "device_federation_outbox",
             entity_column="destination",
@@ -229,7 +229,7 @@ class DataStore(
         )
 
         events_max = self._stream_id_gen.get_current_token()
-        curr_state_delta_prefill, min_curr_state_delta_id = self.db.get_cache_dict(
+        curr_state_delta_prefill, min_curr_state_delta_id = self.db_pool.get_cache_dict(
             db_conn,
             "current_state_delta_stream",
             entity_column="room_id",
@@ -243,7 +243,7 @@ class DataStore(
             prefilled_cache=curr_state_delta_prefill,
         )
 
-        _group_updates_prefill, min_group_updates_id = self.db.get_cache_dict(
+        _group_updates_prefill, min_group_updates_id = self.db_pool.get_cache_dict(
             db_conn,
             "local_group_updates",
             entity_column="user_id",
@@ -282,7 +282,7 @@ class DataStore(
 
         txn = db_conn.cursor()
         txn.execute(sql, (PresenceState.OFFLINE,))
-        rows = self.db.cursor_to_dict(txn)
+        rows = self.db_pool.cursor_to_dict(txn)
         txn.close()
 
         for row in rows:
@@ -295,7 +295,9 @@ class DataStore(
         Counts the number of users who used this homeserver in the last 24 hours.
         """
         yesterday = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24)
-        return self.db.runInteraction("count_daily_users", self._count_users, yesterday)
+        return self.db_pool.runInteraction(
+            "count_daily_users", self._count_users, yesterday
+        )
 
     def count_monthly_users(self):
         """
@@ -305,7 +307,7 @@ class DataStore(
         amongst other things, includes a 3 day grace period before a user counts.
         """
         thirty_days_ago = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30)
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "count_monthly_users", self._count_users, thirty_days_ago
         )
 
@@ -405,7 +407,7 @@ class DataStore(
 
             return results
 
-        return self.db.runInteraction("count_r30_users", _count_r30_users)
+        return self.db_pool.runInteraction("count_r30_users", _count_r30_users)
 
     def _get_start_of_day(self):
         """
@@ -470,7 +472,7 @@ class DataStore(
             # frequently
             self._last_user_visit_update = now
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "generate_user_daily_visits", _generate_user_daily_visits
         )
 
@@ -481,7 +483,7 @@ class DataStore(
         Returns:
             defer.Deferred: resolves to list[dict[str, Any]]
         """
-        return self.db.simple_select_list(
+        return self.db_pool.simple_select_list(
             table="users",
             keyvalues={},
             retcols=[
@@ -543,10 +545,12 @@ class DataStore(
                 where_clause
             )
             txn.execute(sql, args)
-            users = self.db.cursor_to_dict(txn)
+            users = self.db_pool.cursor_to_dict(txn)
             return users, count
 
-        return self.db.runInteraction("get_users_paginate_txn", get_users_paginate_txn)
+        return self.db_pool.runInteraction(
+            "get_users_paginate_txn", get_users_paginate_txn
+        )
 
     def search_users(self, term):
         """Function to search users list for one or more users with
@@ -558,7 +562,7 @@ class DataStore(
         Returns:
             defer.Deferred: resolves to list[dict[str, Any]]
         """
-        return self.db.simple_search_list(
+        return self.db_pool.simple_search_list(
             table="users",
             term=term,
             col="name",
diff --git a/synapse/storage/data_stores/main/account_data.py b/synapse/storage/databases/main/account_data.py
index 33cc372dfd..2193d8fdc5 100644
--- a/synapse/storage/data_stores/main/account_data.py
+++ b/synapse/storage/databases/main/account_data.py
@@ -23,7 +23,7 @@ from canonicaljson import json
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore, db_to_json
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.util.id_generators import StreamIdGenerator
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 from synapse.util.caches.stream_change_cache import StreamChangeCache
@@ -40,7 +40,7 @@ class AccountDataWorkerStore(SQLBaseStore):
     # the abstract methods being implemented.
     __metaclass__ = abc.ABCMeta
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         account_max = self.get_max_account_data_stream_id()
         self._account_data_stream_cache = StreamChangeCache(
             "AccountDataAndTagsChangeCache", account_max
@@ -69,7 +69,7 @@ class AccountDataWorkerStore(SQLBaseStore):
         """
 
         def get_account_data_for_user_txn(txn):
-            rows = self.db.simple_select_list_txn(
+            rows = self.db_pool.simple_select_list_txn(
                 txn,
                 "account_data",
                 {"user_id": user_id},
@@ -80,7 +80,7 @@ class AccountDataWorkerStore(SQLBaseStore):
                 row["account_data_type"]: db_to_json(row["content"]) for row in rows
             }
 
-            rows = self.db.simple_select_list_txn(
+            rows = self.db_pool.simple_select_list_txn(
                 txn,
                 "room_account_data",
                 {"user_id": user_id},
@@ -94,7 +94,7 @@ class AccountDataWorkerStore(SQLBaseStore):
 
             return global_account_data, by_room
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_account_data_for_user", get_account_data_for_user_txn
         )
 
@@ -104,7 +104,7 @@ class AccountDataWorkerStore(SQLBaseStore):
         Returns:
             Deferred: A dict
         """
-        result = yield self.db.simple_select_one_onecol(
+        result = yield self.db_pool.simple_select_one_onecol(
             table="account_data",
             keyvalues={"user_id": user_id, "account_data_type": data_type},
             retcol="content",
@@ -129,7 +129,7 @@ class AccountDataWorkerStore(SQLBaseStore):
         """
 
         def get_account_data_for_room_txn(txn):
-            rows = self.db.simple_select_list_txn(
+            rows = self.db_pool.simple_select_list_txn(
                 txn,
                 "room_account_data",
                 {"user_id": user_id, "room_id": room_id},
@@ -140,7 +140,7 @@ class AccountDataWorkerStore(SQLBaseStore):
                 row["account_data_type"]: db_to_json(row["content"]) for row in rows
             }
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_account_data_for_room", get_account_data_for_room_txn
         )
 
@@ -158,7 +158,7 @@ class AccountDataWorkerStore(SQLBaseStore):
         """
 
         def get_account_data_for_room_and_type_txn(txn):
-            content_json = self.db.simple_select_one_onecol_txn(
+            content_json = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="room_account_data",
                 keyvalues={
@@ -172,7 +172,7 @@ class AccountDataWorkerStore(SQLBaseStore):
 
             return db_to_json(content_json) if content_json else None
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_account_data_for_room_and_type", get_account_data_for_room_and_type_txn
         )
 
@@ -202,7 +202,7 @@ class AccountDataWorkerStore(SQLBaseStore):
             txn.execute(sql, (last_id, current_id, limit))
             return txn.fetchall()
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_updated_global_account_data", get_updated_global_account_data_txn
         )
 
@@ -232,7 +232,7 @@ class AccountDataWorkerStore(SQLBaseStore):
             txn.execute(sql, (last_id, current_id, limit))
             return txn.fetchall()
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_updated_room_account_data", get_updated_room_account_data_txn
         )
 
@@ -277,7 +277,7 @@ class AccountDataWorkerStore(SQLBaseStore):
         if not changed:
             return defer.succeed(({}, {}))
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_updated_account_data_for_user", get_updated_account_data_for_user_txn
         )
 
@@ -295,7 +295,7 @@ class AccountDataWorkerStore(SQLBaseStore):
 
 
 class AccountDataStore(AccountDataWorkerStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         self._account_data_id_gen = StreamIdGenerator(
             db_conn,
             "account_data_max_stream_id",
@@ -333,7 +333,7 @@ class AccountDataStore(AccountDataWorkerStore):
             # no need to lock here as room_account_data has a unique constraint
             # on (user_id, room_id, account_data_type) so simple_upsert will
             # retry if there is a conflict.
-            yield self.db.simple_upsert(
+            yield self.db_pool.simple_upsert(
                 desc="add_room_account_data",
                 table="room_account_data",
                 keyvalues={
@@ -379,7 +379,7 @@ class AccountDataStore(AccountDataWorkerStore):
             # no need to lock here as account_data has a unique constraint on
             # (user_id, account_data_type) so simple_upsert will retry if
             # there is a conflict.
-            yield self.db.simple_upsert(
+            yield self.db_pool.simple_upsert(
                 desc="add_user_account_data",
                 table="account_data",
                 keyvalues={"user_id": user_id, "account_data_type": account_data_type},
@@ -427,4 +427,4 @@ class AccountDataStore(AccountDataWorkerStore):
             )
             txn.execute(update_max_id_sql, (next_id, next_id))
 
-        return self.db.runInteraction("update_account_data_max_stream_id", _update)
+        return self.db_pool.runInteraction("update_account_data_max_stream_id", _update)
diff --git a/synapse/storage/data_stores/main/appservice.py b/synapse/storage/databases/main/appservice.py
index 56659fed37..055a3962dc 100644
--- a/synapse/storage/data_stores/main/appservice.py
+++ b/synapse/storage/databases/main/appservice.py
@@ -23,8 +23,8 @@ from twisted.internet import defer
 from synapse.appservice import AppServiceTransaction
 from synapse.config.appservice import load_appservices
 from synapse.storage._base import SQLBaseStore, db_to_json
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
 
 logger = logging.getLogger(__name__)
 
@@ -49,7 +49,7 @@ def _make_exclusive_regex(services_cache):
 
 
 class ApplicationServiceWorkerStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         self.services_cache = load_appservices(
             hs.hostname, hs.config.app_service_config_files
         )
@@ -134,7 +134,7 @@ class ApplicationServiceTransactionWorkerStore(
             A Deferred which resolves to a list of ApplicationServices, which
             may be empty.
         """
-        results = yield self.db.simple_select_list(
+        results = yield self.db_pool.simple_select_list(
             "application_services_state", {"state": state}, ["as_id"]
         )
         # NB: This assumes this class is linked with ApplicationServiceStore
@@ -156,7 +156,7 @@ class ApplicationServiceTransactionWorkerStore(
         Returns:
             A Deferred which resolves to ApplicationServiceState.
         """
-        result = yield self.db.simple_select_one(
+        result = yield self.db_pool.simple_select_one(
             "application_services_state",
             {"as_id": service.id},
             ["state"],
@@ -176,7 +176,7 @@ class ApplicationServiceTransactionWorkerStore(
         Returns:
             A Deferred which resolves when the state was set successfully.
         """
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             "application_services_state", {"as_id": service.id}, {"state": state}
         )
 
@@ -217,7 +217,9 @@ class ApplicationServiceTransactionWorkerStore(
             )
             return AppServiceTransaction(service=service, id=new_txn_id, events=events)
 
-        return self.db.runInteraction("create_appservice_txn", _create_appservice_txn)
+        return self.db_pool.runInteraction(
+            "create_appservice_txn", _create_appservice_txn
+        )
 
     def complete_appservice_txn(self, txn_id, service):
         """Completes an application service transaction.
@@ -250,7 +252,7 @@ class ApplicationServiceTransactionWorkerStore(
                 )
 
             # Set current txn_id for AS to 'txn_id'
-            self.db.simple_upsert_txn(
+            self.db_pool.simple_upsert_txn(
                 txn,
                 "application_services_state",
                 {"as_id": service.id},
@@ -258,13 +260,13 @@ class ApplicationServiceTransactionWorkerStore(
             )
 
             # Delete txn
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 "application_services_txns",
                 {"txn_id": txn_id, "as_id": service.id},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "complete_appservice_txn", _complete_appservice_txn
         )
 
@@ -288,7 +290,7 @@ class ApplicationServiceTransactionWorkerStore(
                 " ORDER BY txn_id ASC LIMIT 1",
                 (service.id,),
             )
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             if not rows:
                 return None
 
@@ -296,7 +298,7 @@ class ApplicationServiceTransactionWorkerStore(
 
             return entry
 
-        entry = yield self.db.runInteraction(
+        entry = yield self.db_pool.runInteraction(
             "get_oldest_unsent_appservice_txn", _get_oldest_unsent_txn
         )
 
@@ -326,7 +328,7 @@ class ApplicationServiceTransactionWorkerStore(
                 "UPDATE appservice_stream_position SET stream_ordering = ?", (pos,)
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "set_appservice_last_pos", set_appservice_last_pos_txn
         )
 
@@ -355,7 +357,7 @@ class ApplicationServiceTransactionWorkerStore(
 
             return upper_bound, [row[1] for row in rows]
 
-        upper_bound, event_ids = yield self.db.runInteraction(
+        upper_bound, event_ids = yield self.db_pool.runInteraction(
             "get_new_events_for_appservice", get_new_events_for_appservice_txn
         )
 
diff --git a/synapse/storage/data_stores/main/cache.py b/synapse/storage/databases/main/cache.py
index edc3624fed..683afde52b 100644
--- a/synapse/storage/data_stores/main/cache.py
+++ b/synapse/storage/databases/main/cache.py
@@ -26,7 +26,7 @@ from synapse.replication.tcp.streams.events import (
     EventsStreamEventRow,
 )
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.engines import PostgresEngine
 from synapse.util.iterutils import batch_iter
 
@@ -39,7 +39,7 @@ CURRENT_STATE_CACHE_NAME = "cs_cache_fake"
 
 
 class CacheInvalidationWorkerStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
         self._instance_name = hs.get_instance_name()
@@ -92,7 +92,7 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
 
             return updates, upto_token, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_updated_caches", get_all_updated_caches_txn
         )
 
@@ -203,7 +203,7 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
             return
 
         cache_func.invalidate(keys)
-        await self.db.runInteraction(
+        await self.db_pool.runInteraction(
             "invalidate_cache_and_stream",
             self._send_invalidation_to_replication,
             cache_func.__name__,
@@ -288,7 +288,7 @@ class CacheInvalidationWorkerStore(SQLBaseStore):
             if keys is not None:
                 keys = list(keys)
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="cache_invalidation_stream_by_instance",
                 values={
diff --git a/synapse/storage/data_stores/main/censor_events.py b/synapse/storage/databases/main/censor_events.py
index 2d48261724..1de8249563 100644
--- a/synapse/storage/data_stores/main/censor_events.py
+++ b/synapse/storage/databases/main/censor_events.py
@@ -21,10 +21,10 @@ from twisted.internet import defer
 from synapse.events.utils import prune_event_dict
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.cache import CacheInvalidationWorkerStore
-from synapse.storage.data_stores.main.events import encode_json
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.cache import CacheInvalidationWorkerStore
+from synapse.storage.databases.main.events import encode_json
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
@@ -34,7 +34,7 @@ logger = logging.getLogger(__name__)
 
 
 class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs: "HomeServer"):
+    def __init__(self, database: DatabasePool, db_conn, hs: "HomeServer"):
         super().__init__(database, db_conn, hs)
 
         def _censor_redactions():
@@ -56,7 +56,7 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
             return
 
         if not (
-            await self.db.updates.has_completed_background_update(
+            await self.db_pool.updates.has_completed_background_update(
                 "redactions_have_censored_ts_idx"
             )
         ):
@@ -85,7 +85,7 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
             LIMIT ?
         """
 
-        rows = await self.db.execute(
+        rows = await self.db_pool.execute(
             "_censor_redactions_fetch", None, sql, before_ts, 100
         )
 
@@ -123,14 +123,14 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
                 if pruned_json:
                     self._censor_event_txn(txn, event_id, pruned_json)
 
-                self.db.simple_update_one_txn(
+                self.db_pool.simple_update_one_txn(
                     txn,
                     table="redactions",
                     keyvalues={"event_id": redaction_id},
                     updatevalues={"have_censored": True},
                 )
 
-        await self.db.runInteraction("_update_censor_txn", _update_censor_txn)
+        await self.db_pool.runInteraction("_update_censor_txn", _update_censor_txn)
 
     def _censor_event_txn(self, txn, event_id, pruned_json):
         """Censor an event by replacing its JSON in the event_json table with the
@@ -141,7 +141,7 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
             event_id (str): The ID of the event to censor.
             pruned_json (str): The pruned JSON
         """
-        self.db.simple_update_one_txn(
+        self.db_pool.simple_update_one_txn(
             txn,
             table="event_json",
             keyvalues={"event_id": event_id},
@@ -193,7 +193,9 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
                 txn, "_get_event_cache", (event.event_id,)
             )
 
-        yield self.db.runInteraction("delete_expired_event", delete_expired_event_txn)
+        yield self.db_pool.runInteraction(
+            "delete_expired_event", delete_expired_event_txn
+        )
 
     def _delete_event_expiry_txn(self, txn, event_id):
         """Delete the expiry timestamp associated with an event ID without deleting the
@@ -203,6 +205,6 @@ class CensorEventsStore(EventsWorkerStore, CacheInvalidationWorkerStore, SQLBase
             txn (LoggingTransaction): The transaction to use to perform the deletion.
             event_id (str): The event ID to delete the associated expiry timestamp of.
         """
-        return self.db.simple_delete_txn(
+        return self.db_pool.simple_delete_txn(
             txn=txn, table="event_expiry", keyvalues={"event_id": event_id}
         )
diff --git a/synapse/storage/data_stores/main/client_ips.py b/synapse/storage/databases/main/client_ips.py
index 995d4764a9..712c8d0264 100644
--- a/synapse/storage/data_stores/main/client_ips.py
+++ b/synapse/storage/databases/main/client_ips.py
@@ -19,7 +19,7 @@ from twisted.internet import defer
 
 from synapse.metrics.background_process_metrics import wrap_as_background_process
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database, make_tuple_comparison_clause
+from synapse.storage.database import DatabasePool, make_tuple_comparison_clause
 from synapse.util.caches.descriptors import Cache
 
 logger = logging.getLogger(__name__)
@@ -31,40 +31,40 @@ LAST_SEEN_GRANULARITY = 120 * 1000
 
 
 class ClientIpBackgroundUpdateStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(ClientIpBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "user_ips_device_index",
             index_name="user_ips_device_id",
             table="user_ips",
             columns=["user_id", "device_id", "last_seen"],
         )
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "user_ips_last_seen_index",
             index_name="user_ips_last_seen",
             table="user_ips",
             columns=["user_id", "last_seen"],
         )
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "user_ips_last_seen_only_index",
             index_name="user_ips_last_seen_only",
             table="user_ips",
             columns=["last_seen"],
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "user_ips_analyze", self._analyze_user_ip
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "user_ips_remove_dupes", self._remove_user_ip_dupes
         )
 
         # Register a unique index
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "user_ips_device_unique_index",
             index_name="user_ips_user_token_ip_unique_index",
             table="user_ips",
@@ -73,12 +73,12 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
         )
 
         # Drop the old non-unique index
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "user_ips_drop_nonunique_index", self._remove_user_ip_nonunique
         )
 
         # Update the last seen info in devices.
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "devices_last_seen", self._devices_last_seen_update
         )
 
@@ -89,8 +89,10 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
             txn.execute("DROP INDEX IF EXISTS user_ips_user_ip")
             txn.close()
 
-        yield self.db.runWithConnection(f)
-        yield self.db.updates._end_background_update("user_ips_drop_nonunique_index")
+        yield self.db_pool.runWithConnection(f)
+        yield self.db_pool.updates._end_background_update(
+            "user_ips_drop_nonunique_index"
+        )
         return 1
 
     @defer.inlineCallbacks
@@ -104,9 +106,9 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
         def user_ips_analyze(txn):
             txn.execute("ANALYZE user_ips")
 
-        yield self.db.runInteraction("user_ips_analyze", user_ips_analyze)
+        yield self.db_pool.runInteraction("user_ips_analyze", user_ips_analyze)
 
-        yield self.db.updates._end_background_update("user_ips_analyze")
+        yield self.db_pool.updates._end_background_update("user_ips_analyze")
 
         return 1
 
@@ -138,7 +140,7 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
                 return None
 
         # Get a last seen that has roughly `batch_size` since `begin_last_seen`
-        end_last_seen = yield self.db.runInteraction(
+        end_last_seen = yield self.db_pool.runInteraction(
             "user_ips_dups_get_last_seen", get_last_seen
         )
 
@@ -269,14 +271,14 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
                     (user_id, access_token, ip, device_id, user_agent, last_seen),
                 )
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, "user_ips_remove_dupes", {"last_seen": end_last_seen}
             )
 
-        yield self.db.runInteraction("user_ips_dups_remove", remove)
+        yield self.db_pool.runInteraction("user_ips_dups_remove", remove)
 
         if last:
-            yield self.db.updates._end_background_update("user_ips_remove_dupes")
+            yield self.db_pool.updates._end_background_update("user_ips_remove_dupes")
 
         return batch_size
 
@@ -336,7 +338,7 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
             txn.execute_batch(sql, rows)
 
             _, _, _, user_id, device_id = rows[-1]
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn,
                 "devices_last_seen",
                 {"last_user_id": user_id, "last_device_id": device_id},
@@ -344,18 +346,18 @@ class ClientIpBackgroundUpdateStore(SQLBaseStore):
 
             return len(rows)
 
-        updated = yield self.db.runInteraction(
+        updated = yield self.db_pool.runInteraction(
             "_devices_last_seen_update", _devices_last_seen_update_txn
         )
 
         if not updated:
-            yield self.db.updates._end_background_update("devices_last_seen")
+            yield self.db_pool.updates._end_background_update("devices_last_seen")
 
         return updated
 
 
 class ClientIpStore(ClientIpBackgroundUpdateStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
 
         self.client_ip_last_seen = Cache(
             name="client_ip_last_seen", keylen=4, max_entries=50000
@@ -403,18 +405,18 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
     def _update_client_ips_batch(self):
 
         # If the DB pool has already terminated, don't try updating
-        if not self.db.is_running():
+        if not self.db_pool.is_running():
             return
 
         to_update = self._batch_row_update
         self._batch_row_update = {}
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "_update_client_ips_batch", self._update_client_ips_batch_txn, to_update
         )
 
     def _update_client_ips_batch_txn(self, txn, to_update):
-        if "user_ips" in self.db._unsafe_to_upsert_tables or (
+        if "user_ips" in self.db_pool._unsafe_to_upsert_tables or (
             not self.database_engine.can_native_upsert
         ):
             self.database_engine.lock_table(txn, "user_ips")
@@ -423,7 +425,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
             (user_id, access_token, ip), (user_agent, device_id, last_seen) = entry
 
             try:
-                self.db.simple_upsert_txn(
+                self.db_pool.simple_upsert_txn(
                     txn,
                     table="user_ips",
                     keyvalues={
@@ -445,7 +447,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
                     # this is always an update rather than an upsert: the row should
                     # already exist, and if it doesn't, that may be because it has been
                     # deleted, and we don't want to re-create it.
-                    self.db.simple_update_txn(
+                    self.db_pool.simple_update_txn(
                         txn,
                         table="devices",
                         keyvalues={"user_id": user_id, "device_id": device_id},
@@ -477,7 +479,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
         if device_id is not None:
             keyvalues["device_id"] = device_id
 
-        res = yield self.db.simple_select_list(
+        res = yield self.db_pool.simple_select_list(
             table="devices",
             keyvalues=keyvalues,
             retcols=("user_id", "ip", "user_agent", "device_id", "last_seen"),
@@ -510,7 +512,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
                 user_agent, _, last_seen = self._batch_row_update[key]
                 results[(access_token, ip)] = (user_agent, last_seen)
 
-        rows = yield self.db.simple_select_list(
+        rows = yield self.db_pool.simple_select_list(
             table="user_ips",
             keyvalues={"user_id": user_id},
             retcols=["access_token", "ip", "user_agent", "last_seen"],
@@ -540,7 +542,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
             # Nothing to do
             return
 
-        if not await self.db.updates.has_completed_background_update(
+        if not await self.db_pool.updates.has_completed_background_update(
             "devices_last_seen"
         ):
             # Only start pruning if we have finished populating the devices
@@ -573,4 +575,6 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
         def _prune_old_user_ips_txn(txn):
             txn.execute(sql, (timestamp,))
 
-        await self.db.runInteraction("_prune_old_user_ips", _prune_old_user_ips_txn)
+        await self.db_pool.runInteraction(
+            "_prune_old_user_ips", _prune_old_user_ips_txn
+        )
diff --git a/synapse/storage/data_stores/main/deviceinbox.py b/synapse/storage/databases/main/deviceinbox.py
index da297b31fb..874ecdf8d2 100644
--- a/synapse/storage/data_stores/main/deviceinbox.py
+++ b/synapse/storage/databases/main/deviceinbox.py
@@ -22,7 +22,7 @@ from twisted.internet import defer
 
 from synapse.logging.opentracing import log_kv, set_tag, trace
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.util.caches.expiringcache import ExpiringCache
 
 logger = logging.getLogger(__name__)
@@ -70,7 +70,7 @@ class DeviceInboxWorkerStore(SQLBaseStore):
                 stream_pos = current_stream_id
             return messages, stream_pos
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_new_messages_for_device", get_new_messages_for_device_txn
         )
 
@@ -110,7 +110,7 @@ class DeviceInboxWorkerStore(SQLBaseStore):
             txn.execute(sql, (user_id, device_id, up_to_stream_id))
             return txn.rowcount
 
-        count = yield self.db.runInteraction(
+        count = yield self.db_pool.runInteraction(
             "delete_messages_for_device", delete_messages_for_device_txn
         )
 
@@ -179,7 +179,7 @@ class DeviceInboxWorkerStore(SQLBaseStore):
                 stream_pos = current_stream_id
             return messages, stream_pos
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_new_device_msgs_for_remote",
             get_new_messages_for_remote_destination_txn,
         )
@@ -204,7 +204,7 @@ class DeviceInboxWorkerStore(SQLBaseStore):
             )
             txn.execute(sql, (destination, up_to_stream_id))
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "delete_device_msgs_for_remote", delete_messages_for_remote_destination_txn
         )
 
@@ -269,7 +269,7 @@ class DeviceInboxWorkerStore(SQLBaseStore):
 
             return updates, upto_token, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_new_device_messages", get_all_new_device_messages_txn
         )
 
@@ -277,17 +277,17 @@ class DeviceInboxWorkerStore(SQLBaseStore):
 class DeviceInboxBackgroundUpdateStore(SQLBaseStore):
     DEVICE_INBOX_STREAM_ID = "device_inbox_stream_drop"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(DeviceInboxBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "device_inbox_stream_index",
             index_name="device_inbox_stream_id_user_id",
             table="device_inbox",
             columns=["stream_id", "user_id"],
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.DEVICE_INBOX_STREAM_ID, self._background_drop_index_device_inbox
         )
 
@@ -298,9 +298,9 @@ class DeviceInboxBackgroundUpdateStore(SQLBaseStore):
             txn.execute("DROP INDEX IF EXISTS device_inbox_stream_id")
             txn.close()
 
-        yield self.db.runWithConnection(reindex_txn)
+        yield self.db_pool.runWithConnection(reindex_txn)
 
-        yield self.db.updates._end_background_update(self.DEVICE_INBOX_STREAM_ID)
+        yield self.db_pool.updates._end_background_update(self.DEVICE_INBOX_STREAM_ID)
 
         return 1
 
@@ -308,7 +308,7 @@ class DeviceInboxBackgroundUpdateStore(SQLBaseStore):
 class DeviceInboxStore(DeviceInboxWorkerStore, DeviceInboxBackgroundUpdateStore):
     DEVICE_INBOX_STREAM_ID = "device_inbox_stream_drop"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(DeviceInboxStore, self).__init__(database, db_conn, hs)
 
         # Map of (user_id, device_id) to the last stream_id that has been
@@ -360,7 +360,7 @@ class DeviceInboxStore(DeviceInboxWorkerStore, DeviceInboxBackgroundUpdateStore)
 
         with self._device_inbox_id_gen.get_next() as stream_id:
             now_ms = self.clock.time_msec()
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "add_messages_to_device_inbox", add_messages_txn, now_ms, stream_id
             )
             for user_id in local_messages_by_user_then_device.keys():
@@ -380,7 +380,7 @@ class DeviceInboxStore(DeviceInboxWorkerStore, DeviceInboxBackgroundUpdateStore)
             # Check if we've already inserted a matching message_id for that
             # origin. This can happen if the origin doesn't receive our
             # acknowledgement from the first time we received the message.
-            already_inserted = self.db.simple_select_one_txn(
+            already_inserted = self.db_pool.simple_select_one_txn(
                 txn,
                 table="device_federation_inbox",
                 keyvalues={"origin": origin, "message_id": message_id},
@@ -392,7 +392,7 @@ class DeviceInboxStore(DeviceInboxWorkerStore, DeviceInboxBackgroundUpdateStore)
 
             # Add an entry for this message_id so that we know we've processed
             # it.
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="device_federation_inbox",
                 values={
@@ -410,7 +410,7 @@ class DeviceInboxStore(DeviceInboxWorkerStore, DeviceInboxBackgroundUpdateStore)
 
         with self._device_inbox_id_gen.get_next() as stream_id:
             now_ms = self.clock.time_msec()
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "add_messages_from_remote_to_device_inbox",
                 add_messages_txn,
                 now_ms,
diff --git a/synapse/storage/data_stores/main/devices.py b/synapse/storage/databases/main/devices.py
index 45581a6500..88a7aadfc6 100644
--- a/synapse/storage/data_stores/main/devices.py
+++ b/synapse/storage/databases/main/devices.py
@@ -31,7 +31,7 @@ from synapse.logging.opentracing import (
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
 from synapse.storage.database import (
-    Database,
+    DatabasePool,
     LoggingTransaction,
     make_tuple_comparison_clause,
 )
@@ -67,7 +67,7 @@ class DeviceWorkerStore(SQLBaseStore):
         Raises:
             StoreError: if the device is not found
         """
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             table="devices",
             keyvalues={"user_id": user_id, "device_id": device_id, "hidden": False},
             retcols=("user_id", "device_id", "display_name"),
@@ -86,7 +86,7 @@ class DeviceWorkerStore(SQLBaseStore):
             containing "device_id", "user_id" and "display_name" for each
             device.
         """
-        devices = yield self.db.simple_select_list(
+        devices = yield self.db_pool.simple_select_list(
             table="devices",
             keyvalues={"user_id": user_id, "hidden": False},
             retcols=("user_id", "device_id", "display_name"),
@@ -118,7 +118,7 @@ class DeviceWorkerStore(SQLBaseStore):
         if not has_changed:
             return now_stream_id, []
 
-        updates = yield self.db.runInteraction(
+        updates = yield self.db_pool.runInteraction(
             "get_device_updates_by_remote",
             self._get_device_updates_by_remote_txn,
             destination,
@@ -255,7 +255,7 @@ class DeviceWorkerStore(SQLBaseStore):
 
         """
         devices = (
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "_get_e2e_device_keys_txn",
                 self._get_e2e_device_keys_txn,
                 query_map.keys(),
@@ -326,12 +326,12 @@ class DeviceWorkerStore(SQLBaseStore):
             rows = txn.fetchall()
             return rows[0][0]
 
-        return self.db.runInteraction("get_last_device_update_for_remote_user", f)
+        return self.db_pool.runInteraction("get_last_device_update_for_remote_user", f)
 
     def mark_as_sent_devices_by_remote(self, destination, stream_id):
         """Mark that updates have successfully been sent to the destination.
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "mark_as_sent_devices_by_remote",
             self._mark_as_sent_devices_by_remote_txn,
             destination,
@@ -350,7 +350,7 @@ class DeviceWorkerStore(SQLBaseStore):
         txn.execute(sql, (destination, stream_id))
         rows = txn.fetchall()
 
-        self.db.simple_upsert_many_txn(
+        self.db_pool.simple_upsert_many_txn(
             txn=txn,
             table="device_lists_outbound_last_success",
             key_names=("destination", "user_id"),
@@ -376,7 +376,7 @@ class DeviceWorkerStore(SQLBaseStore):
         """
 
         with self._device_list_id_gen.get_next() as stream_id:
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "add_user_sig_change_to_streams",
                 self._add_user_signature_change_txn,
                 from_user_id,
@@ -391,7 +391,7 @@ class DeviceWorkerStore(SQLBaseStore):
             from_user_id,
             stream_id,
         )
-        self.db.simple_insert_txn(
+        self.db_pool.simple_insert_txn(
             txn,
             "user_signature_stream",
             values={
@@ -449,7 +449,7 @@ class DeviceWorkerStore(SQLBaseStore):
 
     @cachedInlineCallbacks(num_args=2, tree=True)
     def _get_cached_user_device(self, user_id, device_id):
-        content = yield self.db.simple_select_one_onecol(
+        content = yield self.db_pool.simple_select_one_onecol(
             table="device_lists_remote_cache",
             keyvalues={"user_id": user_id, "device_id": device_id},
             retcol="content",
@@ -459,7 +459,7 @@ class DeviceWorkerStore(SQLBaseStore):
 
     @cachedInlineCallbacks()
     def get_cached_devices_for_user(self, user_id):
-        devices = yield self.db.simple_select_list(
+        devices = yield self.db_pool.simple_select_list(
             table="device_lists_remote_cache",
             keyvalues={"user_id": user_id},
             retcols=("device_id", "content"),
@@ -475,7 +475,7 @@ class DeviceWorkerStore(SQLBaseStore):
         Returns:
             (stream_id, devices)
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_devices_with_keys_by_user",
             self._get_devices_with_keys_by_user_txn,
             user_id,
@@ -555,7 +555,7 @@ class DeviceWorkerStore(SQLBaseStore):
 
             return changes
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_users_whose_devices_changed", _get_users_whose_devices_changed_txn
         )
 
@@ -574,7 +574,7 @@ class DeviceWorkerStore(SQLBaseStore):
                 SELECT DISTINCT user_ids FROM user_signature_stream
                 WHERE from_user_id = ? AND stream_id > ?
             """
-            rows = yield self.db.execute(
+            rows = yield self.db_pool.execute(
                 "get_users_whose_signatures_changed", None, sql, user_id, from_key
             )
             return {user for row in rows for user in db_to_json(row[0])}
@@ -631,7 +631,7 @@ class DeviceWorkerStore(SQLBaseStore):
 
             return updates, upto_token, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_device_list_changes_for_remotes",
             _get_all_device_list_changes_for_remotes,
         )
@@ -641,7 +641,7 @@ class DeviceWorkerStore(SQLBaseStore):
         """Get the last stream_id we got for a user. May be None if we haven't
         got any information for them.
         """
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="device_lists_remote_extremeties",
             keyvalues={"user_id": user_id},
             retcol="stream_id",
@@ -655,7 +655,7 @@ class DeviceWorkerStore(SQLBaseStore):
         inlineCallbacks=True,
     )
     def get_device_list_last_stream_id_for_remotes(self, user_ids):
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="device_lists_remote_extremeties",
             column="user_id",
             iterable=user_ids,
@@ -680,7 +680,7 @@ class DeviceWorkerStore(SQLBaseStore):
             The IDs of users whose device lists need resync.
         """
         if user_ids:
-            rows = yield self.db.simple_select_many_batch(
+            rows = yield self.db_pool.simple_select_many_batch(
                 table="device_lists_remote_resync",
                 column="user_id",
                 iterable=user_ids,
@@ -688,7 +688,7 @@ class DeviceWorkerStore(SQLBaseStore):
                 desc="get_user_ids_requiring_device_list_resync_with_iterable",
             )
         else:
-            rows = yield self.db.simple_select_list(
+            rows = yield self.db_pool.simple_select_list(
                 table="device_lists_remote_resync",
                 keyvalues=None,
                 retcols=("user_id",),
@@ -701,7 +701,7 @@ class DeviceWorkerStore(SQLBaseStore):
         """Records that the server has reason to believe the cache of the devices
         for the remote users is out of date.
         """
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="device_lists_remote_resync",
             keyvalues={"user_id": user_id},
             values={},
@@ -714,7 +714,7 @@ class DeviceWorkerStore(SQLBaseStore):
         """
 
         def _mark_remote_user_device_list_as_unsubscribed_txn(txn):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="device_lists_remote_extremeties",
                 keyvalues={"user_id": user_id},
@@ -723,17 +723,17 @@ class DeviceWorkerStore(SQLBaseStore):
                 txn, self.get_device_list_last_stream_id_for_remote, (user_id,)
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "mark_remote_user_device_list_as_unsubscribed",
             _mark_remote_user_device_list_as_unsubscribed_txn,
         )
 
 
 class DeviceBackgroundUpdateStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(DeviceBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "device_lists_stream_idx",
             index_name="device_lists_stream_user_id",
             table="device_lists_stream",
@@ -741,7 +741,7 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
         )
 
         # create a unique index on device_lists_remote_cache
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "device_lists_remote_cache_unique_idx",
             index_name="device_lists_remote_cache_unique_id",
             table="device_lists_remote_cache",
@@ -750,7 +750,7 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
         )
 
         # And one on device_lists_remote_extremeties
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "device_lists_remote_extremeties_unique_idx",
             index_name="device_lists_remote_extremeties_unique_idx",
             table="device_lists_remote_extremeties",
@@ -759,22 +759,22 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
         )
 
         # once they complete, we can remove the old non-unique indexes.
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             DROP_DEVICE_LIST_STREAMS_NON_UNIQUE_INDEXES,
             self._drop_device_list_streams_non_unique_indexes,
         )
 
         # clear out duplicate device list outbound pokes
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             BG_UPDATE_REMOVE_DUP_OUTBOUND_POKES, self._remove_duplicate_outbound_pokes,
         )
 
         # a pair of background updates that were added during the 1.14 release cycle,
         # but replaced with 58/06dlols_unique_idx.py
-        self.db.updates.register_noop_background_update(
+        self.db_pool.updates.register_noop_background_update(
             "device_lists_outbound_last_success_unique_idx",
         )
-        self.db.updates.register_noop_background_update(
+        self.db_pool.updates.register_noop_background_update(
             "drop_device_lists_outbound_last_success_non_unique_idx",
         )
 
@@ -786,8 +786,8 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
             txn.execute("DROP INDEX IF EXISTS device_lists_remote_extremeties_id")
             txn.close()
 
-        yield self.db.runWithConnection(f)
-        yield self.db.updates._end_background_update(
+        yield self.db_pool.runWithConnection(f)
+        yield self.db_pool.updates._end_background_update(
             DROP_DEVICE_LIST_STREAMS_NON_UNIQUE_INDEXES
         )
         return 1
@@ -807,7 +807,7 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
 
         def _txn(txn):
             clause, args = make_tuple_comparison_clause(
-                self.db.engine, [(x, last_row[x]) for x in KEY_COLS]
+                self.db_pool.engine, [(x, last_row[x]) for x in KEY_COLS]
             )
             sql = """
                 SELECT stream_id, destination, user_id, device_id, MAX(ts) AS ts
@@ -823,30 +823,32 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
                 ",".join(KEY_COLS),  # ORDER BY
             )
             txn.execute(sql, args + [batch_size])
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
 
             row = None
             for row in rows:
-                self.db.simple_delete_txn(
+                self.db_pool.simple_delete_txn(
                     txn, "device_lists_outbound_pokes", {x: row[x] for x in KEY_COLS},
                 )
 
                 row["sent"] = False
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn, "device_lists_outbound_pokes", row,
                 )
 
             if row:
-                self.db.updates._background_update_progress_txn(
+                self.db_pool.updates._background_update_progress_txn(
                     txn, BG_UPDATE_REMOVE_DUP_OUTBOUND_POKES, {"last_row": row},
                 )
 
             return len(rows)
 
-        rows = await self.db.runInteraction(BG_UPDATE_REMOVE_DUP_OUTBOUND_POKES, _txn)
+        rows = await self.db_pool.runInteraction(
+            BG_UPDATE_REMOVE_DUP_OUTBOUND_POKES, _txn
+        )
 
         if not rows:
-            await self.db.updates._end_background_update(
+            await self.db_pool.updates._end_background_update(
                 BG_UPDATE_REMOVE_DUP_OUTBOUND_POKES
             )
 
@@ -854,7 +856,7 @@ class DeviceBackgroundUpdateStore(SQLBaseStore):
 
 
 class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(DeviceStore, self).__init__(database, db_conn, hs)
 
         # Map of (user_id, device_id) -> bool. If there is an entry that implies
@@ -885,7 +887,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             return False
 
         try:
-            inserted = yield self.db.simple_insert(
+            inserted = yield self.db_pool.simple_insert(
                 "devices",
                 values={
                     "user_id": user_id,
@@ -899,7 +901,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             if not inserted:
                 # if the device already exists, check if it's a real device, or
                 # if the device ID is reserved by something else
-                hidden = yield self.db.simple_select_one_onecol(
+                hidden = yield self.db_pool.simple_select_one_onecol(
                     "devices",
                     keyvalues={"user_id": user_id, "device_id": device_id},
                     retcol="hidden",
@@ -934,7 +936,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         Returns:
             defer.Deferred
         """
-        yield self.db.simple_delete_one(
+        yield self.db_pool.simple_delete_one(
             table="devices",
             keyvalues={"user_id": user_id, "device_id": device_id, "hidden": False},
             desc="delete_device",
@@ -952,7 +954,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         Returns:
             defer.Deferred
         """
-        yield self.db.simple_delete_many(
+        yield self.db_pool.simple_delete_many(
             table="devices",
             column="device_id",
             iterable=device_ids,
@@ -981,7 +983,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             updates["display_name"] = new_display_name
         if not updates:
             return defer.succeed(None)
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="devices",
             keyvalues={"user_id": user_id, "device_id": device_id, "hidden": False},
             updatevalues=updates,
@@ -1005,7 +1007,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         Returns:
             Deferred[None]
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "update_remote_device_list_cache_entry",
             self._update_remote_device_list_cache_entry_txn,
             user_id,
@@ -1018,7 +1020,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         self, txn, user_id, device_id, content, stream_id
     ):
         if content.get("deleted"):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="device_lists_remote_cache",
                 keyvalues={"user_id": user_id, "device_id": device_id},
@@ -1026,7 +1028,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
 
             txn.call_after(self.device_id_exists_cache.invalidate, (user_id, device_id))
         else:
-            self.db.simple_upsert_txn(
+            self.db_pool.simple_upsert_txn(
                 txn,
                 table="device_lists_remote_cache",
                 keyvalues={"user_id": user_id, "device_id": device_id},
@@ -1042,7 +1044,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             self.get_device_list_last_stream_id_for_remote.invalidate, (user_id,)
         )
 
-        self.db.simple_upsert_txn(
+        self.db_pool.simple_upsert_txn(
             txn,
             table="device_lists_remote_extremeties",
             keyvalues={"user_id": user_id},
@@ -1066,7 +1068,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         Returns:
             Deferred[None]
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "update_remote_device_list_cache",
             self._update_remote_device_list_cache_txn,
             user_id,
@@ -1075,11 +1077,11 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         )
 
     def _update_remote_device_list_cache_txn(self, txn, user_id, devices, stream_id):
-        self.db.simple_delete_txn(
+        self.db_pool.simple_delete_txn(
             txn, table="device_lists_remote_cache", keyvalues={"user_id": user_id}
         )
 
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="device_lists_remote_cache",
             values=[
@@ -1098,7 +1100,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             self.get_device_list_last_stream_id_for_remote.invalidate, (user_id,)
         )
 
-        self.db.simple_upsert_txn(
+        self.db_pool.simple_upsert_txn(
             txn,
             table="device_lists_remote_extremeties",
             keyvalues={"user_id": user_id},
@@ -1111,7 +1113,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         # If we're replacing the remote user's device list cache presumably
         # we've done a full resync, so we remove the entry that says we need
         # to resync
-        self.db.simple_delete_txn(
+        self.db_pool.simple_delete_txn(
             txn, table="device_lists_remote_resync", keyvalues={"user_id": user_id},
         )
 
@@ -1124,7 +1126,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             return
 
         with self._device_list_id_gen.get_next_mult(len(device_ids)) as stream_ids:
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "add_device_change_to_stream",
                 self._add_device_change_to_stream_txn,
                 user_id,
@@ -1139,7 +1141,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         with self._device_list_id_gen.get_next_mult(
             len(hosts) * len(device_ids)
         ) as stream_ids:
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "add_device_outbound_poke_to_stream",
                 self._add_device_outbound_poke_to_stream_txn,
                 user_id,
@@ -1174,7 +1176,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
             [(user_id, device_id, min_stream_id) for device_id in device_ids],
         )
 
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="device_lists_stream",
             values=[
@@ -1196,7 +1198,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
         now = self._clock.time_msec()
         next_stream_id = iter(stream_ids)
 
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="device_lists_outbound_pokes",
             values=[
@@ -1303,7 +1305,7 @@ class DeviceStore(DeviceWorkerStore, DeviceBackgroundUpdateStore):
 
         return run_as_background_process(
             "prune_old_outbound_device_pokes",
-            self.db.runInteraction,
+            self.db_pool.runInteraction,
             "_prune_old_outbound_device_pokes",
             _prune_txn,
         )
diff --git a/synapse/storage/data_stores/main/directory.py b/synapse/storage/databases/main/directory.py
index e1d1bc3e05..7819bfcbb3 100644
--- a/synapse/storage/data_stores/main/directory.py
+++ b/synapse/storage/databases/main/directory.py
@@ -37,7 +37,7 @@ class DirectoryWorkerStore(SQLBaseStore):
             Deferred: results in namedtuple with keys "room_id" and
             "servers" or None if no association can be found
         """
-        room_id = yield self.db.simple_select_one_onecol(
+        room_id = yield self.db_pool.simple_select_one_onecol(
             "room_aliases",
             {"room_alias": room_alias.to_string()},
             "room_id",
@@ -48,7 +48,7 @@ class DirectoryWorkerStore(SQLBaseStore):
         if not room_id:
             return None
 
-        servers = yield self.db.simple_select_onecol(
+        servers = yield self.db_pool.simple_select_onecol(
             "room_alias_servers",
             {"room_alias": room_alias.to_string()},
             "server",
@@ -61,7 +61,7 @@ class DirectoryWorkerStore(SQLBaseStore):
         return RoomAliasMapping(room_id, room_alias.to_string(), servers)
 
     def get_room_alias_creator(self, room_alias):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="room_aliases",
             keyvalues={"room_alias": room_alias},
             retcol="creator",
@@ -70,7 +70,7 @@ class DirectoryWorkerStore(SQLBaseStore):
 
     @cached(max_entries=5000)
     def get_aliases_for_room(self, room_id):
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             "room_aliases",
             {"room_id": room_id},
             "room_alias",
@@ -94,7 +94,7 @@ class DirectoryStore(DirectoryWorkerStore):
         """
 
         def alias_txn(txn):
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 "room_aliases",
                 {
@@ -104,7 +104,7 @@ class DirectoryStore(DirectoryWorkerStore):
                 },
             )
 
-            self.db.simple_insert_many_txn(
+            self.db_pool.simple_insert_many_txn(
                 txn,
                 table="room_alias_servers",
                 values=[
@@ -118,7 +118,7 @@ class DirectoryStore(DirectoryWorkerStore):
             )
 
         try:
-            ret = yield self.db.runInteraction(
+            ret = yield self.db_pool.runInteraction(
                 "create_room_alias_association", alias_txn
             )
         except self.database_engine.module.IntegrityError:
@@ -129,7 +129,7 @@ class DirectoryStore(DirectoryWorkerStore):
 
     @defer.inlineCallbacks
     def delete_room_alias(self, room_alias):
-        room_id = yield self.db.runInteraction(
+        room_id = yield self.db_pool.runInteraction(
             "delete_room_alias", self._delete_room_alias_txn, room_alias
         )
 
@@ -190,6 +190,6 @@ class DirectoryStore(DirectoryWorkerStore):
                 txn, self.get_aliases_for_room, (new_room_id,)
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "_update_aliases_for_room_txn", _update_aliases_for_room_txn
         )
diff --git a/synapse/storage/data_stores/main/e2e_room_keys.py b/synapse/storage/databases/main/e2e_room_keys.py
index 615364f018..90152edc3c 100644
--- a/synapse/storage/data_stores/main/e2e_room_keys.py
+++ b/synapse/storage/databases/main/e2e_room_keys.py
@@ -38,7 +38,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             StoreError
         """
 
-        yield self.db.simple_update_one(
+        yield self.db_pool.simple_update_one(
             table="e2e_room_keys",
             keyvalues={
                 "user_id": user_id,
@@ -89,7 +89,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
                 }
             )
 
-        yield self.db.simple_insert_many(
+        yield self.db_pool.simple_insert_many(
             table="e2e_room_keys", values=values, desc="add_e2e_room_keys"
         )
 
@@ -125,7 +125,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             if session_id:
                 keyvalues["session_id"] = session_id
 
-        rows = yield self.db.simple_select_list(
+        rows = yield self.db_pool.simple_select_list(
             table="e2e_room_keys",
             keyvalues=keyvalues,
             retcols=(
@@ -171,7 +171,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
            Deferred[dict[str, dict[str, dict]]]: a map of room IDs to session IDs to room key
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_e2e_room_keys_multi",
             self._get_e2e_room_keys_multi_txn,
             user_id,
@@ -235,7 +235,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             version (str): the version ID of the backup we're querying about
         """
 
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="e2e_room_keys",
             keyvalues={"user_id": user_id, "version": version},
             retcol="COUNT(*)",
@@ -268,7 +268,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             if session_id:
                 keyvalues["session_id"] = session_id
 
-        yield self.db.simple_delete(
+        yield self.db_pool.simple_delete(
             table="e2e_room_keys", keyvalues=keyvalues, desc="delete_e2e_room_keys"
         )
 
@@ -313,7 +313,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
                     # it isn't there.
                     raise StoreError(404, "No row found")
 
-            result = self.db.simple_select_one_txn(
+            result = self.db_pool.simple_select_one_txn(
                 txn,
                 table="e2e_room_keys_versions",
                 keyvalues={"user_id": user_id, "version": this_version, "deleted": 0},
@@ -325,7 +325,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
                 result["etag"] = 0
             return result
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_e2e_room_keys_version_info", _get_e2e_room_keys_version_info_txn
         )
 
@@ -353,7 +353,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
 
             new_version = str(int(current_version) + 1)
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="e2e_room_keys_versions",
                 values={
@@ -366,7 +366,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
 
             return new_version
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "create_e2e_room_keys_version_txn", _create_e2e_room_keys_version_txn
         )
 
@@ -392,7 +392,7 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             updatevalues["etag"] = version_etag
 
         if updatevalues:
-            return self.db.simple_update(
+            return self.db_pool.simple_update(
                 table="e2e_room_keys_versions",
                 keyvalues={"user_id": user_id, "version": version},
                 updatevalues=updatevalues,
@@ -421,19 +421,19 @@ class EndToEndRoomKeyStore(SQLBaseStore):
             else:
                 this_version = version
 
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="e2e_room_keys",
                 keyvalues={"user_id": user_id, "version": this_version},
             )
 
-            return self.db.simple_update_one_txn(
+            return self.db_pool.simple_update_one_txn(
                 txn,
                 table="e2e_room_keys_versions",
                 keyvalues={"user_id": user_id, "version": this_version},
                 updatevalues={"deleted": 1},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "delete_e2e_room_keys_version", _delete_e2e_room_keys_version_txn
         )
diff --git a/synapse/storage/data_stores/main/end_to_end_keys.py b/synapse/storage/databases/main/end_to_end_keys.py
index 317c07a829..40354b8304 100644
--- a/synapse/storage/data_stores/main/end_to_end_keys.py
+++ b/synapse/storage/databases/main/end_to_end_keys.py
@@ -51,7 +51,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
         if not query_list:
             return {}
 
-        results = yield self.db.runInteraction(
+        results = yield self.db_pool.runInteraction(
             "get_e2e_device_keys",
             self._get_e2e_device_keys_txn,
             query_list,
@@ -128,7 +128,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
         )
 
         txn.execute(sql, query_params)
-        rows = self.db.cursor_to_dict(txn)
+        rows = self.db_pool.cursor_to_dict(txn)
 
         result = {}
         for row in rows:
@@ -146,7 +146,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
         )
 
         txn.execute(signature_sql, signature_query_params)
-        rows = self.db.cursor_to_dict(txn)
+        rows = self.db_pool.cursor_to_dict(txn)
 
         # add each cross-signing signature to the correct device in the result dict.
         for row in rows:
@@ -189,7 +189,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             key_id) to json string for key
         """
 
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="e2e_one_time_keys_json",
             column="key_id",
             iterable=key_ids,
@@ -222,7 +222,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             # a unique constraint. If there is a race of two calls to
             # `add_e2e_one_time_keys` then they'll conflict and we will only
             # insert one set.
-            self.db.simple_insert_many_txn(
+            self.db_pool.simple_insert_many_txn(
                 txn,
                 table="e2e_one_time_keys_json",
                 values=[
@@ -241,7 +241,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
                 txn, self.count_e2e_one_time_keys, (user_id, device_id)
             )
 
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "add_e2e_one_time_keys_insert", _add_e2e_one_time_keys
         )
 
@@ -264,7 +264,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
                 result[algorithm] = key_count
             return result
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "count_e2e_one_time_keys", _count_e2e_one_time_keys
         )
 
@@ -318,7 +318,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
                 to None.
 
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_bare_e2e_cross_signing_keys_bulk",
             self._get_bare_e2e_cross_signing_keys_bulk_txn,
             user_ids,
@@ -361,7 +361,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             )
 
             txn.execute(sql, params)
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
 
             for row in rows:
                 user_id = row["user_id"]
@@ -420,7 +420,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
                 query_params.extend(item)
 
             txn.execute(sql, query_params)
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
 
             # and add the signatures to the appropriate keys
             for row in rows:
@@ -470,7 +470,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
         result = yield self._get_bare_e2e_cross_signing_keys_bulk(user_ids)
 
         if from_user_id:
-            result = yield self.db.runInteraction(
+            result = yield self.db_pool.runInteraction(
                 "get_e2e_cross_signing_signatures",
                 self._get_e2e_cross_signing_signatures_txn,
                 result,
@@ -531,7 +531,7 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
 
             return updates, upto_token, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_user_signature_changes_for_remotes",
             _get_all_user_signature_changes_for_remotes_txn,
         )
@@ -549,7 +549,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
             set_tag("time_now", time_now)
             set_tag("device_keys", device_keys)
 
-            old_key_json = self.db.simple_select_one_onecol_txn(
+            old_key_json = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="e2e_device_keys_json",
                 keyvalues={"user_id": user_id, "device_id": device_id},
@@ -565,7 +565,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 log_kv({"Message": "Device key already stored."})
                 return False
 
-            self.db.simple_upsert_txn(
+            self.db_pool.simple_upsert_txn(
                 txn,
                 table="e2e_device_keys_json",
                 keyvalues={"user_id": user_id, "device_id": device_id},
@@ -574,7 +574,9 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
             log_kv({"message": "Device keys stored."})
             return True
 
-        return self.db.runInteraction("set_e2e_device_keys", _set_e2e_device_keys_txn)
+        return self.db_pool.runInteraction(
+            "set_e2e_device_keys", _set_e2e_device_keys_txn
+        )
 
     def claim_e2e_one_time_keys(self, query_list):
         """Take a list of one time keys out of the database"""
@@ -613,7 +615,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 )
             return result
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "claim_e2e_one_time_keys", _claim_e2e_one_time_keys
         )
 
@@ -626,12 +628,12 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                     "user_id": user_id,
                 }
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="e2e_device_keys_json",
                 keyvalues={"user_id": user_id, "device_id": device_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="e2e_one_time_keys_json",
                 keyvalues={"user_id": user_id, "device_id": device_id},
@@ -640,7 +642,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 txn, self.count_e2e_one_time_keys, (user_id, device_id)
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "delete_e2e_keys_by_device", delete_e2e_keys_by_device_txn
         )
 
@@ -679,7 +681,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
         # We only need to do this for local users, since remote servers should be
         # responsible for checking this for their own users.
         if self.hs.is_mine_id(user_id):
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 "devices",
                 values={
@@ -692,7 +694,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
 
         # and finally, store the key itself
         with self._cross_signing_id_gen.get_next() as stream_id:
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 "e2e_cross_signing_keys",
                 values={
@@ -715,7 +717,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
             key_type (str): the type of cross-signing key to set
             key (dict): the key data
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "add_e2e_cross_signing_key",
             self._set_e2e_cross_signing_key_txn,
             user_id,
@@ -730,7 +732,7 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
             user_id (str): the user who made the signatures
             signatures (iterable[SignatureListItem]): signatures to add
         """
-        return self.db.simple_insert_many(
+        return self.db_pool.simple_insert_many(
             "e2e_cross_signing_signatures",
             [
                 {
diff --git a/synapse/storage/data_stores/main/event_federation.py b/synapse/storage/databases/main/event_federation.py
index a6bb3221ff..eddb32b4d3 100644
--- a/synapse/storage/data_stores/main/event_federation.py
+++ b/synapse/storage/databases/main/event_federation.py
@@ -22,9 +22,9 @@ from twisted.internet import defer
 from synapse.api.errors import StoreError
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import SQLBaseStore, make_in_list_sql_clause
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.data_stores.main.signatures import SignatureWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
+from synapse.storage.databases.main.signatures import SignatureWorkerStore
 from synapse.util.caches.descriptors import cached
 from synapse.util.iterutils import batch_iter
 
@@ -65,7 +65,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         Returns:
             list of event_ids
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_auth_chain_ids",
             self._get_auth_chain_ids_txn,
             event_ids,
@@ -114,7 +114,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             Deferred[Set[str]]
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_auth_chain_difference",
             self._get_auth_chain_difference_txn,
             state_sets,
@@ -260,12 +260,12 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         return {eid for eid, n in event_to_missing_sets.items() if n}
 
     def get_oldest_events_in_room(self, room_id):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_oldest_events_in_room", self._get_oldest_events_in_room_txn, room_id
         )
 
     def get_oldest_events_with_depth_in_room(self, room_id):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_oldest_events_with_depth_in_room",
             self.get_oldest_events_with_depth_in_room_txn,
             room_id,
@@ -296,7 +296,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         Returns
             Deferred[int]
         """
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="events",
             column="event_id",
             iterable=event_ids,
@@ -310,7 +310,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             return max(row["depth"] for row in rows)
 
     def _get_oldest_events_in_room_txn(self, txn, room_id):
-        return self.db.simple_select_onecol_txn(
+        return self.db_pool.simple_select_onecol_txn(
             txn,
             table="event_backward_extremities",
             keyvalues={"room_id": room_id},
@@ -332,7 +332,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
 
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_prev_events_for_room", self._get_prev_events_for_room_txn, room_id
         )
 
@@ -387,13 +387,13 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             txn.execute(sql, query_args)
             return [room_id for room_id, in txn]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_rooms_with_many_extremities", _get_rooms_with_many_extremities_txn
         )
 
     @cached(max_entries=5000, iterable=True)
     def get_latest_event_ids_in_room(self, room_id):
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="event_forward_extremities",
             keyvalues={"room_id": room_id},
             retcol="event_id",
@@ -403,12 +403,12 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
     def get_min_depth(self, room_id):
         """ For hte given room, get the minimum depth we have seen for it.
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_min_depth", self._get_min_depth_interaction, room_id
         )
 
     def _get_min_depth_interaction(self, txn, room_id):
-        min_depth = self.db.simple_select_one_onecol_txn(
+        min_depth = self.db_pool.simple_select_one_onecol_txn(
             txn,
             table="room_depth",
             keyvalues={"room_id": room_id},
@@ -474,7 +474,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             txn.execute(sql, (stream_ordering, room_id))
             return [event_id for event_id, in txn]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_forward_extremeties_for_room", get_forward_extremeties_for_room_txn
         )
 
@@ -489,7 +489,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             limit (int)
         """
         return (
-            self.db.runInteraction(
+            self.db_pool.runInteraction(
                 "get_backfill_events",
                 self._get_backfill_events,
                 room_id,
@@ -520,7 +520,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         queue = PriorityQueue()
 
         for event_id in event_list:
-            depth = self.db.simple_select_one_onecol_txn(
+            depth = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="events",
                 keyvalues={"event_id": event_id, "room_id": room_id},
@@ -552,7 +552,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
 
     @defer.inlineCallbacks
     def get_missing_events(self, room_id, earliest_events, latest_events, limit):
-        ids = yield self.db.runInteraction(
+        ids = yield self.db_pool.runInteraction(
             "get_missing_events",
             self._get_missing_events,
             room_id,
@@ -605,7 +605,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         Returns:
             Deferred[list[str]]
         """
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="event_edges",
             column="prev_event_id",
             iterable=event_ids,
@@ -628,10 +628,10 @@ class EventFederationStore(EventFederationWorkerStore):
 
     EVENT_AUTH_STATE_ONLY = "event_auth_state_only"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(EventFederationStore, self).__init__(database, db_conn, hs)
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.EVENT_AUTH_STATE_ONLY, self._background_delete_non_state_event_auth
         )
 
@@ -658,13 +658,13 @@ class EventFederationStore(EventFederationWorkerStore):
 
         return run_as_background_process(
             "delete_old_forward_extrem_cache",
-            self.db.runInteraction,
+            self.db_pool.runInteraction,
             "_delete_old_forward_extrem_cache",
             _delete_old_forward_extrem_cache_txn,
         )
 
     def clean_room_for_join(self, room_id):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "clean_room_for_join", self._clean_room_for_join_txn, room_id
         )
 
@@ -708,17 +708,19 @@ class EventFederationStore(EventFederationWorkerStore):
                 "max_stream_id_exclusive": min_stream_id,
             }
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, self.EVENT_AUTH_STATE_ONLY, new_progress
             )
 
             return min_stream_id >= target_min_stream_id
 
-        result = yield self.db.runInteraction(
+        result = yield self.db_pool.runInteraction(
             self.EVENT_AUTH_STATE_ONLY, delete_event_auth
         )
 
         if not result:
-            yield self.db.updates._end_background_update(self.EVENT_AUTH_STATE_ONLY)
+            yield self.db_pool.updates._end_background_update(
+                self.EVENT_AUTH_STATE_ONLY
+            )
 
         return batch_size
diff --git a/synapse/storage/data_stores/main/event_push_actions.py b/synapse/storage/databases/main/event_push_actions.py
index ad82838901..b8cefb4d5e 100644
--- a/synapse/storage/data_stores/main/event_push_actions.py
+++ b/synapse/storage/databases/main/event_push_actions.py
@@ -21,7 +21,7 @@ from canonicaljson import json
 
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import LoggingTransaction, SQLBaseStore, db_to_json
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.util.caches.descriptors import cachedInlineCallbacks
 
 logger = logging.getLogger(__name__)
@@ -66,7 +66,7 @@ def _deserialize_action(actions, is_highlight):
 
 
 class EventPushActionsWorkerStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(EventPushActionsWorkerStore, self).__init__(database, db_conn, hs)
 
         # These get correctly set by _find_stream_orderings_for_times_txn
@@ -91,7 +91,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
     def get_unread_event_push_actions_by_room_for_user(
         self, room_id, user_id, last_read_event_id
     ):
-        ret = yield self.db.runInteraction(
+        ret = yield self.db_pool.runInteraction(
             "get_unread_event_push_actions_by_room",
             self._get_unread_counts_by_receipt_txn,
             room_id,
@@ -176,7 +176,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             txn.execute(sql, (min_stream_ordering, max_stream_ordering))
             return [r[0] for r in txn]
 
-        ret = await self.db.runInteraction("get_push_action_users_in_range", f)
+        ret = await self.db_pool.runInteraction("get_push_action_users_in_range", f)
         return ret
 
     async def get_unread_push_actions_for_user_in_range_for_http(
@@ -230,7 +230,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             txn.execute(sql, args)
             return txn.fetchall()
 
-        after_read_receipt = await self.db.runInteraction(
+        after_read_receipt = await self.db_pool.runInteraction(
             "get_unread_push_actions_for_user_in_range_http_arr", get_after_receipt
         )
 
@@ -258,7 +258,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             txn.execute(sql, args)
             return txn.fetchall()
 
-        no_read_receipt = await self.db.runInteraction(
+        no_read_receipt = await self.db_pool.runInteraction(
             "get_unread_push_actions_for_user_in_range_http_nrr", get_no_receipt
         )
 
@@ -332,7 +332,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             txn.execute(sql, args)
             return txn.fetchall()
 
-        after_read_receipt = await self.db.runInteraction(
+        after_read_receipt = await self.db_pool.runInteraction(
             "get_unread_push_actions_for_user_in_range_email_arr", get_after_receipt
         )
 
@@ -360,7 +360,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             txn.execute(sql, args)
             return txn.fetchall()
 
-        no_read_receipt = await self.db.runInteraction(
+        no_read_receipt = await self.db_pool.runInteraction(
             "get_unread_push_actions_for_user_in_range_email_nrr", get_no_receipt
         )
 
@@ -410,7 +410,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             txn.execute(sql, (user_id, min_stream_ordering))
             return bool(txn.fetchone())
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_if_maybe_push_in_range_for_user",
             _get_if_maybe_push_in_range_for_user_txn,
         )
@@ -461,7 +461,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
                 ),
             )
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "add_push_actions_to_staging", _add_push_actions_to_staging_txn
         )
 
@@ -471,7 +471,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
         """
 
         try:
-            res = await self.db.simple_delete(
+            res = await self.db_pool.simple_delete(
                 table="event_push_actions_staging",
                 keyvalues={"event_id": event_id},
                 desc="remove_push_actions_from_staging",
@@ -488,7 +488,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
     def _find_stream_orderings_for_times(self):
         return run_as_background_process(
             "event_push_action_stream_orderings",
-            self.db.runInteraction,
+            self.db_pool.runInteraction,
             "_find_stream_orderings_for_times",
             self._find_stream_orderings_for_times_txn,
         )
@@ -524,7 +524,7 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             Deferred[int]: stream ordering of the first event received on/after
                 the timestamp
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "_find_first_stream_ordering_after_ts_txn",
             self._find_first_stream_ordering_after_ts_txn,
             ts,
@@ -619,24 +619,26 @@ class EventPushActionsWorkerStore(SQLBaseStore):
             txn.execute(sql, (stream_ordering,))
             return txn.fetchone()
 
-        result = await self.db.runInteraction("get_time_of_last_push_action_before", f)
+        result = await self.db_pool.runInteraction(
+            "get_time_of_last_push_action_before", f
+        )
         return result[0] if result else None
 
 
 class EventPushActionsStore(EventPushActionsWorkerStore):
     EPA_HIGHLIGHT_INDEX = "epa_highlight_index"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(EventPushActionsStore, self).__init__(database, db_conn, hs)
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             self.EPA_HIGHLIGHT_INDEX,
             index_name="event_push_actions_u_highlight",
             table="event_push_actions",
             columns=["user_id", "stream_ordering"],
         )
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "event_push_actions_highlights_index",
             index_name="event_push_actions_highlights_index",
             table="event_push_actions",
@@ -678,9 +680,9 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
                 " LIMIT ?" % (before_clause,)
             )
             txn.execute(sql, args)
-            return self.db.cursor_to_dict(txn)
+            return self.db_pool.cursor_to_dict(txn)
 
-        push_actions = await self.db.runInteraction("get_push_actions_for_user", f)
+        push_actions = await self.db_pool.runInteraction("get_push_actions_for_user", f)
         for pa in push_actions:
             pa["actions"] = _deserialize_action(pa["actions"], pa["highlight"])
         return push_actions
@@ -690,7 +692,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
             txn.execute("SELECT MAX(stream_ordering) FROM event_push_actions")
             return txn.fetchone()
 
-        result = await self.db.runInteraction(
+        result = await self.db_pool.runInteraction(
             "get_latest_push_action_stream_ordering", f
         )
         return result[0] or 0
@@ -753,7 +755,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
             while True:
                 logger.info("Rotating notifications")
 
-                caught_up = await self.db.runInteraction(
+                caught_up = await self.db_pool.runInteraction(
                     "_rotate_notifs", self._rotate_notifs_txn
                 )
                 if caught_up:
@@ -767,7 +769,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
         the archiving process has caught up or not.
         """
 
-        old_rotate_stream_ordering = self.db.simple_select_one_onecol_txn(
+        old_rotate_stream_ordering = self.db_pool.simple_select_one_onecol_txn(
             txn,
             table="event_push_summary_stream_ordering",
             keyvalues={},
@@ -803,7 +805,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
         return caught_up
 
     def _rotate_notifs_before_txn(self, txn, rotate_to_stream_ordering):
-        old_rotate_stream_ordering = self.db.simple_select_one_onecol_txn(
+        old_rotate_stream_ordering = self.db_pool.simple_select_one_onecol_txn(
             txn,
             table="event_push_summary_stream_ordering",
             keyvalues={},
@@ -835,7 +837,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
         # If the `old.user_id` above is NULL then we know there isn't already an
         # entry in the table, so we simply insert it. Otherwise we update the
         # existing table.
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="event_push_summary",
             values=[
diff --git a/synapse/storage/data_stores/main/events.py b/synapse/storage/databases/main/events.py
index 0c9c02afa1..4d8a24ce4b 100644
--- a/synapse/storage/data_stores/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -32,8 +32,8 @@ from synapse.events import EventBase  # noqa: F401
 from synapse.events.snapshot import EventContext  # noqa: F401
 from synapse.logging.utils import log_function
 from synapse.storage._base import db_to_json, make_in_list_sql_clause
-from synapse.storage.data_stores.main.search import SearchEntry
-from synapse.storage.database import Database, LoggingTransaction
+from synapse.storage.database import DatabasePool, LoggingTransaction
+from synapse.storage.databases.main.search import SearchEntry
 from synapse.storage.util.id_generators import StreamIdGenerator
 from synapse.types import StateMap, get_domain_from_id
 from synapse.util.frozenutils import frozendict_json_encoder
@@ -41,7 +41,7 @@ from synapse.util.iterutils import batch_iter
 
 if TYPE_CHECKING:
     from synapse.server import HomeServer
-    from synapse.storage.data_stores.main import DataStore
+    from synapse.storage.databases.main import DataStore
 
 
 logger = logging.getLogger(__name__)
@@ -132,9 +132,11 @@ class PersistEventsStore:
     Note: This is not part of the `DataStore` mixin.
     """
 
-    def __init__(self, hs: "HomeServer", db: Database, main_data_store: "DataStore"):
+    def __init__(
+        self, hs: "HomeServer", db: DatabasePool, main_data_store: "DataStore"
+    ):
         self.hs = hs
-        self.db = db
+        self.db_pool = db
         self.store = main_data_store
         self.database_engine = db.engine
         self._clock = hs.get_clock()
@@ -207,7 +209,7 @@ class PersistEventsStore:
             for (event, context), stream in zip(events_and_contexts, stream_orderings):
                 event.internal_metadata.stream_ordering = stream
 
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "persist_events",
                 self._persist_events_txn,
                 events_and_contexts=events_and_contexts,
@@ -283,7 +285,7 @@ class PersistEventsStore:
             results.extend(r[0] for r in txn if not db_to_json(r[1]).get("soft_failed"))
 
         for chunk in batch_iter(event_ids, 100):
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "_get_events_which_are_prevs", _get_events_which_are_prevs_txn, chunk
             )
 
@@ -347,7 +349,7 @@ class PersistEventsStore:
                         existing_prevs.add(prev_event_id)
 
         for chunk in batch_iter(event_ids, 100):
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "_get_prevs_before_rejected", _get_prevs_before_rejected_txn, chunk
             )
 
@@ -421,7 +423,7 @@ class PersistEventsStore:
         # event's auth chain, but its easier for now just to store them (and
         # it doesn't take much storage compared to storing the entire event
         # anyway).
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="event_auth",
             values=[
@@ -484,7 +486,7 @@ class PersistEventsStore:
                 """
                 txn.execute(sql, (stream_id, room_id))
 
-                self.db.simple_delete_txn(
+                self.db_pool.simple_delete_txn(
                     txn, table="current_state_events", keyvalues={"room_id": room_id},
                 )
             else:
@@ -632,7 +634,7 @@ class PersistEventsStore:
             creator = content.get("creator")
             room_version_id = content.get("room_version", RoomVersions.V1.identifier)
 
-            self.db.simple_upsert_txn(
+            self.db_pool.simple_upsert_txn(
                 txn,
                 table="rooms",
                 keyvalues={"room_id": room_id},
@@ -644,14 +646,14 @@ class PersistEventsStore:
         self, txn, new_forward_extremities, max_stream_order
     ):
         for room_id, new_extrem in new_forward_extremities.items():
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn, table="event_forward_extremities", keyvalues={"room_id": room_id}
             )
             txn.call_after(
                 self.store.get_latest_event_ids_in_room.invalidate, (room_id,)
             )
 
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="event_forward_extremities",
             values=[
@@ -664,7 +666,7 @@ class PersistEventsStore:
         # new stream_ordering to new forward extremeties in the room.
         # This allows us to later efficiently look up the forward extremeties
         # for a room before a given stream_ordering
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="stream_ordering_to_exterm",
             values=[
@@ -788,7 +790,7 @@ class PersistEventsStore:
                 # change in outlier status to our workers.
                 stream_order = event.internal_metadata.stream_ordering
                 state_group_id = context.state_group
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     table="ex_outlier_stream",
                     values={
@@ -826,7 +828,7 @@ class PersistEventsStore:
             d.pop("redacted_because", None)
             return d
 
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="event_json",
             values=[
@@ -843,7 +845,7 @@ class PersistEventsStore:
             ],
         )
 
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="events",
             values=[
@@ -873,7 +875,7 @@ class PersistEventsStore:
                 # If we're persisting an unredacted event we go and ensure
                 # that we mark any redactions that reference this event as
                 # requiring censoring.
-                self.db.simple_update_txn(
+                self.db_pool.simple_update_txn(
                     txn,
                     table="redactions",
                     keyvalues={"redacts": event.event_id},
@@ -1015,7 +1017,9 @@ class PersistEventsStore:
 
             state_values.append(vals)
 
-        self.db.simple_insert_many_txn(txn, table="state_events", values=state_values)
+        self.db_pool.simple_insert_many_txn(
+            txn, table="state_events", values=state_values
+        )
 
         # Prefill the event cache
         self._add_to_cache(txn, events_and_contexts)
@@ -1046,7 +1050,7 @@ class PersistEventsStore:
             )
 
             txn.execute(sql + clause, args)
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             for row in rows:
                 event = ev_map[row["event_id"]]
                 if not row["rejects"] and not row["redacts"]:
@@ -1066,7 +1070,7 @@ class PersistEventsStore:
         # invalidate the cache for the redacted event
         txn.call_after(self.store._invalidate_get_event_cache, event.redacts)
 
-        self.db.simple_insert_txn(
+        self.db_pool.simple_insert_txn(
             txn,
             table="redactions",
             values={
@@ -1089,7 +1093,7 @@ class PersistEventsStore:
             room_id (str): The ID of the room the event was sent to.
             topological_ordering (int): The position of the event in the room's topology.
         """
-        return self.db.simple_insert_many_txn(
+        return self.db_pool.simple_insert_many_txn(
             txn=txn,
             table="event_labels",
             values=[
@@ -1111,7 +1115,7 @@ class PersistEventsStore:
             event_id (str): The event ID the expiry timestamp is associated with.
             expiry_ts (int): The timestamp at which to expire (delete) the event.
         """
-        return self.db.simple_insert_txn(
+        return self.db_pool.simple_insert_txn(
             txn=txn,
             table="event_expiry",
             values={"event_id": event_id, "expiry_ts": expiry_ts},
@@ -1135,12 +1139,14 @@ class PersistEventsStore:
                 }
             )
 
-        self.db.simple_insert_many_txn(txn, table="event_reference_hashes", values=vals)
+        self.db_pool.simple_insert_many_txn(
+            txn, table="event_reference_hashes", values=vals
+        )
 
     def _store_room_members_txn(self, txn, events, backfilled):
         """Store a room member in the database.
         """
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="room_memberships",
             values=[
@@ -1180,7 +1186,7 @@ class PersistEventsStore:
                 and event.internal_metadata.is_outlier()
                 and event.internal_metadata.is_out_of_band_membership()
             ):
-                self.db.simple_upsert_txn(
+                self.db_pool.simple_upsert_txn(
                     txn,
                     table="local_current_membership",
                     keyvalues={"room_id": event.room_id, "user_id": event.state_key},
@@ -1218,7 +1224,7 @@ class PersistEventsStore:
 
         aggregation_key = relation.get("key")
 
-        self.db.simple_insert_txn(
+        self.db_pool.simple_insert_txn(
             txn,
             table="event_relations",
             values={
@@ -1246,7 +1252,7 @@ class PersistEventsStore:
             redacted_event_id (str): The event that was redacted.
         """
 
-        self.db.simple_delete_txn(
+        self.db_pool.simple_delete_txn(
             txn, table="event_relations", keyvalues={"event_id": redacted_event_id}
         )
 
@@ -1282,7 +1288,7 @@ class PersistEventsStore:
                 # Ignore the event if one of the value isn't an integer.
                 return
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn=txn,
                 table="room_retention",
                 values={
@@ -1363,7 +1369,7 @@ class PersistEventsStore:
             )
 
         for event, _ in events_and_contexts:
-            user_ids = self.db.simple_select_onecol_txn(
+            user_ids = self.db_pool.simple_select_onecol_txn(
                 txn,
                 table="event_push_actions_staging",
                 keyvalues={"event_id": event.event_id},
@@ -1395,7 +1401,7 @@ class PersistEventsStore:
         )
 
     def _store_rejections_txn(self, txn, event_id, reason):
-        self.db.simple_insert_txn(
+        self.db_pool.simple_insert_txn(
             txn,
             table="rejections",
             values={
@@ -1421,7 +1427,7 @@ class PersistEventsStore:
 
             state_groups[event.event_id] = context.state_group
 
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="event_to_state_groups",
             values=[
@@ -1443,7 +1449,7 @@ class PersistEventsStore:
         if min_depth is not None and depth >= min_depth:
             return
 
-        self.db.simple_upsert_txn(
+        self.db_pool.simple_upsert_txn(
             txn,
             table="room_depth",
             keyvalues={"room_id": room_id},
@@ -1455,7 +1461,7 @@ class PersistEventsStore:
         For the given event, update the event edges table and forward and
         backward extremities tables.
         """
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="event_edges",
             values=[
diff --git a/synapse/storage/data_stores/main/events_bg_updates.py b/synapse/storage/databases/main/events_bg_updates.py
index 663c94b24f..35a0e09e3c 100644
--- a/synapse/storage/data_stores/main/events_bg_updates.py
+++ b/synapse/storage/databases/main/events_bg_updates.py
@@ -19,7 +19,7 @@ from twisted.internet import defer
 
 from synapse.api.constants import EventContentFields
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 
 logger = logging.getLogger(__name__)
 
@@ -30,18 +30,18 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
     EVENT_FIELDS_SENDER_URL_UPDATE_NAME = "event_fields_sender_url"
     DELETE_SOFT_FAILED_EXTREMITIES = "delete_soft_failed_extremities"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(EventsBackgroundUpdatesStore, self).__init__(database, db_conn, hs)
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.EVENT_ORIGIN_SERVER_TS_NAME, self._background_reindex_origin_server_ts
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME,
             self._background_reindex_fields_sender,
         )
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "event_contains_url_index",
             index_name="event_contains_url_index",
             table="events",
@@ -52,7 +52,7 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
         # an event_id index on event_search is useful for the purge_history
         # api. Plus it means we get to enforce some integrity with a UNIQUE
         # clause
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "event_search_event_id_idx",
             index_name="event_search_event_id_idx",
             table="event_search",
@@ -61,16 +61,16 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
             psql_only=True,
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.DELETE_SOFT_FAILED_EXTREMITIES, self._cleanup_extremities_bg_update
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "redactions_received_ts", self._redactions_received_ts
         )
 
         # This index gets deleted in `event_fix_redactions_bytes` update
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "event_fix_redactions_bytes_create_index",
             index_name="redactions_censored_redacts",
             table="redactions",
@@ -78,15 +78,15 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
             where_clause="have_censored",
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "event_fix_redactions_bytes", self._event_fix_redactions_bytes
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "event_store_labels", self._event_store_labels
         )
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "redactions_have_censored_ts_idx",
             index_name="redactions_have_censored_ts",
             table="redactions",
@@ -149,18 +149,18 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
                 "rows_inserted": rows_inserted + len(rows),
             }
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME, progress
             )
 
             return len(rows)
 
-        result = yield self.db.runInteraction(
+        result = yield self.db_pool.runInteraction(
             self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME, reindex_txn
         )
 
         if not result:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME
             )
 
@@ -195,7 +195,7 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
 
             chunks = [event_ids[i : i + 100] for i in range(0, len(event_ids), 100)]
             for chunk in chunks:
-                ev_rows = self.db.simple_select_many_txn(
+                ev_rows = self.db_pool.simple_select_many_txn(
                     txn,
                     table="event_json",
                     column="event_id",
@@ -228,18 +228,18 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
                 "rows_inserted": rows_inserted + len(rows_to_update),
             }
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, self.EVENT_ORIGIN_SERVER_TS_NAME, progress
             )
 
             return len(rows_to_update)
 
-        result = yield self.db.runInteraction(
+        result = yield self.db_pool.runInteraction(
             self.EVENT_ORIGIN_SERVER_TS_NAME, reindex_search_txn
         )
 
         if not result:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 self.EVENT_ORIGIN_SERVER_TS_NAME
             )
 
@@ -374,7 +374,7 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
 
             to_delete.intersection_update(original_set)
 
-            deleted = self.db.simple_delete_many_txn(
+            deleted = self.db_pool.simple_delete_many_txn(
                 txn=txn,
                 table="event_forward_extremities",
                 column="event_id",
@@ -390,7 +390,7 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
 
             if deleted:
                 # We now need to invalidate the caches of these rooms
-                rows = self.db.simple_select_many_txn(
+                rows = self.db_pool.simple_select_many_txn(
                     txn,
                     table="events",
                     column="event_id",
@@ -404,7 +404,7 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
                         self.get_latest_event_ids_in_room.invalidate, (room_id,)
                     )
 
-            self.db.simple_delete_many_txn(
+            self.db_pool.simple_delete_many_txn(
                 txn=txn,
                 table="_extremities_to_check",
                 column="event_id",
@@ -414,19 +414,19 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
 
             return len(original_set)
 
-        num_handled = yield self.db.runInteraction(
+        num_handled = yield self.db_pool.runInteraction(
             "_cleanup_extremities_bg_update", _cleanup_extremities_bg_update_txn
         )
 
         if not num_handled:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 self.DELETE_SOFT_FAILED_EXTREMITIES
             )
 
             def _drop_table_txn(txn):
                 txn.execute("DROP TABLE _extremities_to_check")
 
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "_cleanup_extremities_bg_update_drop_table", _drop_table_txn
             )
 
@@ -474,18 +474,18 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
 
             txn.execute(sql, (self._clock.time_msec(), last_event_id, upper_event_id))
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, "redactions_received_ts", {"last_event_id": upper_event_id}
             )
 
             return len(rows)
 
-        count = yield self.db.runInteraction(
+        count = yield self.db_pool.runInteraction(
             "_redactions_received_ts", _redactions_received_ts_txn
         )
 
         if not count:
-            yield self.db.updates._end_background_update("redactions_received_ts")
+            yield self.db_pool.updates._end_background_update("redactions_received_ts")
 
         return count
 
@@ -511,11 +511,11 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
 
             txn.execute("DROP INDEX redactions_censored_redacts")
 
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "_event_fix_redactions_bytes", _event_fix_redactions_bytes_txn
         )
 
-        yield self.db.updates._end_background_update("event_fix_redactions_bytes")
+        yield self.db_pool.updates._end_background_update("event_fix_redactions_bytes")
 
         return 1
 
@@ -543,7 +543,7 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
                 try:
                     event_json = db_to_json(event_json_raw)
 
-                    self.db.simple_insert_many_txn(
+                    self.db_pool.simple_insert_many_txn(
                         txn=txn,
                         table="event_labels",
                         values=[
@@ -569,17 +569,17 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
                 nbrows += 1
                 last_row_event_id = event_id
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, "event_store_labels", {"last_event_id": last_row_event_id}
             )
 
             return nbrows
 
-        num_rows = yield self.db.runInteraction(
+        num_rows = yield self.db_pool.runInteraction(
             desc="event_store_labels", func=_event_store_labels_txn
         )
 
         if not num_rows:
-            yield self.db.updates._end_background_update("event_store_labels")
+            yield self.db_pool.updates._end_background_update("event_store_labels")
 
         return num_rows
diff --git a/synapse/storage/data_stores/main/events_worker.py b/synapse/storage/databases/main/events_worker.py
index b03b259636..a7b7393f6e 100644
--- a/synapse/storage/data_stores/main/events_worker.py
+++ b/synapse/storage/databases/main/events_worker.py
@@ -40,7 +40,7 @@ from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.replication.tcp.streams import BackfillStream
 from synapse.replication.tcp.streams.events import EventsStream
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.types import Cursor
 from synapse.storage.util.id_generators import StreamIdGenerator
 from synapse.types import get_domain_from_id
@@ -80,7 +80,7 @@ class EventRedactBehaviour(Names):
 
 
 class EventsWorkerStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(EventsWorkerStore, self).__init__(database, db_conn, hs)
 
         if hs.config.worker.writers.events == hs.get_instance_name():
@@ -136,7 +136,7 @@ class EventsWorkerStore(SQLBaseStore):
             Deferred[int|None]: Timestamp in milliseconds, or None for events
             that were persisted before received_ts was implemented.
         """
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="events",
             keyvalues={"event_id": event_id},
             retcol="received_ts",
@@ -175,7 +175,7 @@ class EventsWorkerStore(SQLBaseStore):
 
             return ts
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_approximate_received_ts", _get_approximate_received_ts_txn
         )
 
@@ -543,7 +543,7 @@ class EventsWorkerStore(SQLBaseStore):
                     event_id for events, _ in event_list for event_id in events
                 }
 
-                row_dict = self.db.new_transaction(
+                row_dict = self.db_pool.new_transaction(
                     conn, "do_fetch", [], [], self._fetch_event_rows, events_to_fetch
                 )
 
@@ -720,7 +720,7 @@ class EventsWorkerStore(SQLBaseStore):
 
         if should_start:
             run_as_background_process(
-                "fetch_events", self.db.runWithConnection, self._do_fetch
+                "fetch_events", self.db_pool.runWithConnection, self._do_fetch
             )
 
         logger.debug("Loading %d events: %s", len(events), events)
@@ -889,7 +889,7 @@ class EventsWorkerStore(SQLBaseStore):
         """Given a list of event ids, check if we have already processed and
         stored them as non outliers.
         """
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="events",
             retcols=("event_id",),
             column="event_id",
@@ -924,7 +924,7 @@ class EventsWorkerStore(SQLBaseStore):
         # break the input up into chunks of 100
         input_iterator = iter(event_ids)
         for chunk in iter(lambda: list(itertools.islice(input_iterator, 100)), []):
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "have_seen_events", have_seen_events_txn, chunk
             )
         return results
@@ -953,7 +953,7 @@ class EventsWorkerStore(SQLBaseStore):
         Returns:
             Deferred[int]
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_total_state_event_counts",
             self._get_total_state_event_counts_txn,
             room_id,
@@ -978,7 +978,7 @@ class EventsWorkerStore(SQLBaseStore):
         Returns:
             Deferred[int]
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_current_state_event_counts",
             self._get_current_state_event_counts_txn,
             room_id,
@@ -1043,7 +1043,7 @@ class EventsWorkerStore(SQLBaseStore):
             txn.execute(sql, (last_id, current_id, limit))
             return txn.fetchall()
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_all_new_forward_event_rows", get_all_new_forward_event_rows
         )
 
@@ -1077,7 +1077,7 @@ class EventsWorkerStore(SQLBaseStore):
             txn.execute(sql, (last_id, current_id))
             return txn.fetchall()
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_ex_outlier_stream_rows", get_ex_outlier_stream_rows_txn
         )
 
@@ -1151,7 +1151,7 @@ class EventsWorkerStore(SQLBaseStore):
 
             return new_event_updates, upper_bound, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_new_backfill_event_rows", get_all_new_backfill_event_rows
         )
 
@@ -1199,7 +1199,7 @@ class EventsWorkerStore(SQLBaseStore):
         # we need to make sure that, for every stream id in the results, we get *all*
         # the rows with that stream id.
 
-        rows = await self.db.runInteraction(
+        rows = await self.db_pool.runInteraction(
             "get_all_updated_current_state_deltas",
             get_all_updated_current_state_deltas_txn,
         )  # type: List[Tuple]
@@ -1222,7 +1222,7 @@ class EventsWorkerStore(SQLBaseStore):
         # stream id. let's run the query again, without a row limit, but for
         # just one stream id.
         to_token += 1
-        rows = await self.db.runInteraction(
+        rows = await self.db_pool.runInteraction(
             "get_deltas_for_stream_id", get_deltas_for_stream_id_txn, to_token
         )
 
@@ -1317,7 +1317,7 @@ class EventsWorkerStore(SQLBaseStore):
                 backward_ex_outliers,
             )
 
-        return self.db.runInteraction("get_all_new_events", get_all_new_events_txn)
+        return self.db_pool.runInteraction("get_all_new_events", get_all_new_events_txn)
 
     async def is_event_after(self, event_id1, event_id2):
         """Returns True if event_id1 is after event_id2 in the stream
@@ -1328,7 +1328,7 @@ class EventsWorkerStore(SQLBaseStore):
 
     @cachedInlineCallbacks(max_entries=5000)
     def get_event_ordering(self, event_id):
-        res = yield self.db.simple_select_one(
+        res = yield self.db_pool.simple_select_one(
             table="events",
             retcols=["topological_ordering", "stream_ordering"],
             keyvalues={"event_id": event_id},
@@ -1360,7 +1360,7 @@ class EventsWorkerStore(SQLBaseStore):
 
             return txn.fetchone()
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             desc="get_next_event_to_expire", func=get_next_event_to_expire_txn
         )
 
@@ -1385,7 +1385,7 @@ class EventsWorkerStore(SQLBaseStore):
                 on_invalidate=cache_context.invalidate,
             )
 
-            return await self.db.runInteraction(
+            return await self.db_pool.runInteraction(
                 "get_unread_message_count_for_user",
                 self._get_unread_message_count_for_user_txn,
                 user_id,
@@ -1402,7 +1402,7 @@ class EventsWorkerStore(SQLBaseStore):
     ) -> int:
         if last_read_event_id:
             # Get the stream ordering for the last read event.
-            stream_ordering = self.db.simple_select_one_onecol_txn(
+            stream_ordering = self.db_pool.simple_select_one_onecol_txn(
                 txn=txn,
                 table="events",
                 keyvalues={"room_id": room_id, "event_id": last_read_event_id},
diff --git a/synapse/storage/data_stores/main/filtering.py b/synapse/storage/databases/main/filtering.py
index 342d6622a4..cae6bda80e 100644
--- a/synapse/storage/data_stores/main/filtering.py
+++ b/synapse/storage/databases/main/filtering.py
@@ -30,7 +30,7 @@ class FilteringStore(SQLBaseStore):
         except ValueError:
             raise SynapseError(400, "Invalid filter ID", Codes.INVALID_PARAM)
 
-        def_json = yield self.db.simple_select_one_onecol(
+        def_json = yield self.db_pool.simple_select_one_onecol(
             table="user_filters",
             keyvalues={"user_id": user_localpart, "filter_id": filter_id},
             retcol="filter_json",
@@ -71,4 +71,4 @@ class FilteringStore(SQLBaseStore):
 
             return filter_id
 
-        return self.db.runInteraction("add_user_filter", _do_txn)
+        return self.db_pool.runInteraction("add_user_filter", _do_txn)
diff --git a/synapse/storage/data_stores/main/group_server.py b/synapse/storage/databases/main/group_server.py
index 01ff561e1a..a98181f445 100644
--- a/synapse/storage/data_stores/main/group_server.py
+++ b/synapse/storage/databases/main/group_server.py
@@ -31,7 +31,7 @@ _DEFAULT_ROLE_ID = ""
 
 class GroupServerWorkerStore(SQLBaseStore):
     def get_group(self, group_id):
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             table="groups",
             keyvalues={"group_id": group_id},
             retcols=(
@@ -53,7 +53,7 @@ class GroupServerWorkerStore(SQLBaseStore):
         if not include_private:
             keyvalues["is_public"] = True
 
-        return self.db.simple_select_list(
+        return self.db_pool.simple_select_list(
             table="group_users",
             keyvalues=keyvalues,
             retcols=("user_id", "is_public", "is_admin"),
@@ -63,7 +63,7 @@ class GroupServerWorkerStore(SQLBaseStore):
     def get_invited_users_in_group(self, group_id):
         # TODO: Pagination
 
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="group_invites",
             keyvalues={"group_id": group_id},
             retcol="user_id",
@@ -117,7 +117,9 @@ class GroupServerWorkerStore(SQLBaseStore):
                 for room_id, is_public in txn
             ]
 
-        return self.db.runInteraction("get_rooms_in_group", _get_rooms_in_group_txn)
+        return self.db_pool.runInteraction(
+            "get_rooms_in_group", _get_rooms_in_group_txn
+        )
 
     def get_rooms_for_summary_by_category(
         self, group_id: str, include_private: bool = False,
@@ -205,13 +207,13 @@ class GroupServerWorkerStore(SQLBaseStore):
 
             return rooms, categories
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_rooms_for_summary", _get_rooms_for_summary_txn
         )
 
     @defer.inlineCallbacks
     def get_group_categories(self, group_id):
-        rows = yield self.db.simple_select_list(
+        rows = yield self.db_pool.simple_select_list(
             table="group_room_categories",
             keyvalues={"group_id": group_id},
             retcols=("category_id", "is_public", "profile"),
@@ -228,7 +230,7 @@ class GroupServerWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def get_group_category(self, group_id, category_id):
-        category = yield self.db.simple_select_one(
+        category = yield self.db_pool.simple_select_one(
             table="group_room_categories",
             keyvalues={"group_id": group_id, "category_id": category_id},
             retcols=("is_public", "profile"),
@@ -241,7 +243,7 @@ class GroupServerWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def get_group_roles(self, group_id):
-        rows = yield self.db.simple_select_list(
+        rows = yield self.db_pool.simple_select_list(
             table="group_roles",
             keyvalues={"group_id": group_id},
             retcols=("role_id", "is_public", "profile"),
@@ -258,7 +260,7 @@ class GroupServerWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def get_group_role(self, group_id, role_id):
-        role = yield self.db.simple_select_one(
+        role = yield self.db_pool.simple_select_one(
             table="group_roles",
             keyvalues={"group_id": group_id, "role_id": role_id},
             retcols=("is_public", "profile"),
@@ -277,7 +279,7 @@ class GroupServerWorkerStore(SQLBaseStore):
             Deferred[list[str]]: A twisted.Deferred containing a list of group ids
                 containing this room
         """
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="group_rooms",
             keyvalues={"room_id": room_id},
             retcol="group_id",
@@ -341,12 +343,12 @@ class GroupServerWorkerStore(SQLBaseStore):
 
             return users, roles
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_users_for_summary_by_role", _get_users_for_summary_txn
         )
 
     def is_user_in_group(self, user_id, group_id):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="group_users",
             keyvalues={"group_id": group_id, "user_id": user_id},
             retcol="user_id",
@@ -355,7 +357,7 @@ class GroupServerWorkerStore(SQLBaseStore):
         ).addCallback(lambda r: bool(r))
 
     def is_user_admin_in_group(self, group_id, user_id):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="group_users",
             keyvalues={"group_id": group_id, "user_id": user_id},
             retcol="is_admin",
@@ -366,7 +368,7 @@ class GroupServerWorkerStore(SQLBaseStore):
     def is_user_invited_to_local_group(self, group_id, user_id):
         """Has the group server invited a user?
         """
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="group_invites",
             keyvalues={"group_id": group_id, "user_id": user_id},
             retcol="user_id",
@@ -389,7 +391,7 @@ class GroupServerWorkerStore(SQLBaseStore):
         """
 
         def _get_users_membership_in_group_txn(txn):
-            row = self.db.simple_select_one_txn(
+            row = self.db_pool.simple_select_one_txn(
                 txn,
                 table="group_users",
                 keyvalues={"group_id": group_id, "user_id": user_id},
@@ -404,7 +406,7 @@ class GroupServerWorkerStore(SQLBaseStore):
                     "is_privileged": row["is_admin"],
                 }
 
-            row = self.db.simple_select_one_onecol_txn(
+            row = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="group_invites",
                 keyvalues={"group_id": group_id, "user_id": user_id},
@@ -417,14 +419,14 @@ class GroupServerWorkerStore(SQLBaseStore):
 
             return {}
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_users_membership_info_in_group", _get_users_membership_in_group_txn
         )
 
     def get_publicised_groups_for_user(self, user_id):
         """Get all groups a user is publicising
         """
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="local_group_membership",
             keyvalues={"user_id": user_id, "membership": "join", "is_publicised": True},
             retcol="group_id",
@@ -441,9 +443,9 @@ class GroupServerWorkerStore(SQLBaseStore):
                 WHERE valid_until_ms <= ?
             """
             txn.execute(sql, (valid_until_ms,))
-            return self.db.cursor_to_dict(txn)
+            return self.db_pool.cursor_to_dict(txn)
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_attestations_need_renewals", _get_attestations_need_renewals_txn
         )
 
@@ -452,7 +454,7 @@ class GroupServerWorkerStore(SQLBaseStore):
         """Get the attestation that proves the remote agrees that the user is
         in the group.
         """
-        row = yield self.db.simple_select_one(
+        row = yield self.db_pool.simple_select_one(
             table="group_attestations_remote",
             keyvalues={"group_id": group_id, "user_id": user_id},
             retcols=("valid_until_ms", "attestation_json"),
@@ -467,7 +469,7 @@ class GroupServerWorkerStore(SQLBaseStore):
         return None
 
     def get_joined_groups(self, user_id):
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="local_group_membership",
             keyvalues={"user_id": user_id, "membership": "join"},
             retcol="group_id",
@@ -494,7 +496,7 @@ class GroupServerWorkerStore(SQLBaseStore):
                 for row in txn
             ]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_all_groups_for_user", _get_all_groups_for_user_txn
         )
 
@@ -524,7 +526,7 @@ class GroupServerWorkerStore(SQLBaseStore):
                 for group_id, membership, gtype, content_json in txn
             ]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_groups_changes_for_user", _get_groups_changes_for_user_txn
         )
 
@@ -579,7 +581,7 @@ class GroupServerWorkerStore(SQLBaseStore):
 
             return updates, upto_token, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_groups_changes", _get_all_groups_changes_txn
         )
 
@@ -592,7 +594,7 @@ class GroupServerStore(GroupServerWorkerStore):
          * "invite"
          * "open"
         """
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="groups",
             keyvalues={"group_id": group_id},
             updatevalues={"join_policy": join_policy},
@@ -600,7 +602,7 @@ class GroupServerStore(GroupServerWorkerStore):
         )
 
     def add_room_to_summary(self, group_id, room_id, category_id, order, is_public):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "add_room_to_summary",
             self._add_room_to_summary_txn,
             group_id,
@@ -624,7 +626,7 @@ class GroupServerStore(GroupServerWorkerStore):
                 an order of 1 will put the room first. Otherwise, the room gets
                 added to the end.
         """
-        room_in_group = self.db.simple_select_one_onecol_txn(
+        room_in_group = self.db_pool.simple_select_one_onecol_txn(
             txn,
             table="group_rooms",
             keyvalues={"group_id": group_id, "room_id": room_id},
@@ -637,7 +639,7 @@ class GroupServerStore(GroupServerWorkerStore):
         if category_id is None:
             category_id = _DEFAULT_CATEGORY_ID
         else:
-            cat_exists = self.db.simple_select_one_onecol_txn(
+            cat_exists = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="group_room_categories",
                 keyvalues={"group_id": group_id, "category_id": category_id},
@@ -648,7 +650,7 @@ class GroupServerStore(GroupServerWorkerStore):
                 raise SynapseError(400, "Category doesn't exist")
 
             # TODO: Check category is part of summary already
-            cat_exists = self.db.simple_select_one_onecol_txn(
+            cat_exists = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="group_summary_room_categories",
                 keyvalues={"group_id": group_id, "category_id": category_id},
@@ -668,7 +670,7 @@ class GroupServerStore(GroupServerWorkerStore):
                     (group_id, category_id, group_id, category_id),
                 )
 
-        existing = self.db.simple_select_one_txn(
+        existing = self.db_pool.simple_select_one_txn(
             txn,
             table="group_summary_rooms",
             keyvalues={
@@ -701,7 +703,7 @@ class GroupServerStore(GroupServerWorkerStore):
                 to_update["room_order"] = order
             if is_public is not None:
                 to_update["is_public"] = is_public
-            self.db.simple_update_txn(
+            self.db_pool.simple_update_txn(
                 txn,
                 table="group_summary_rooms",
                 keyvalues={
@@ -715,7 +717,7 @@ class GroupServerStore(GroupServerWorkerStore):
             if is_public is None:
                 is_public = True
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="group_summary_rooms",
                 values={
@@ -731,7 +733,7 @@ class GroupServerStore(GroupServerWorkerStore):
         if category_id is None:
             category_id = _DEFAULT_CATEGORY_ID
 
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             table="group_summary_rooms",
             keyvalues={
                 "group_id": group_id,
@@ -757,7 +759,7 @@ class GroupServerStore(GroupServerWorkerStore):
         else:
             update_values["is_public"] = is_public
 
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="group_room_categories",
             keyvalues={"group_id": group_id, "category_id": category_id},
             values=update_values,
@@ -766,7 +768,7 @@ class GroupServerStore(GroupServerWorkerStore):
         )
 
     def remove_group_category(self, group_id, category_id):
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             table="group_room_categories",
             keyvalues={"group_id": group_id, "category_id": category_id},
             desc="remove_group_category",
@@ -788,7 +790,7 @@ class GroupServerStore(GroupServerWorkerStore):
         else:
             update_values["is_public"] = is_public
 
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="group_roles",
             keyvalues={"group_id": group_id, "role_id": role_id},
             values=update_values,
@@ -797,14 +799,14 @@ class GroupServerStore(GroupServerWorkerStore):
         )
 
     def remove_group_role(self, group_id, role_id):
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             table="group_roles",
             keyvalues={"group_id": group_id, "role_id": role_id},
             desc="remove_group_role",
         )
 
     def add_user_to_summary(self, group_id, user_id, role_id, order, is_public):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "add_user_to_summary",
             self._add_user_to_summary_txn,
             group_id,
@@ -828,7 +830,7 @@ class GroupServerStore(GroupServerWorkerStore):
                 an order of 1 will put the user first. Otherwise, the user gets
                 added to the end.
         """
-        user_in_group = self.db.simple_select_one_onecol_txn(
+        user_in_group = self.db_pool.simple_select_one_onecol_txn(
             txn,
             table="group_users",
             keyvalues={"group_id": group_id, "user_id": user_id},
@@ -841,7 +843,7 @@ class GroupServerStore(GroupServerWorkerStore):
         if role_id is None:
             role_id = _DEFAULT_ROLE_ID
         else:
-            role_exists = self.db.simple_select_one_onecol_txn(
+            role_exists = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="group_roles",
                 keyvalues={"group_id": group_id, "role_id": role_id},
@@ -852,7 +854,7 @@ class GroupServerStore(GroupServerWorkerStore):
                 raise SynapseError(400, "Role doesn't exist")
 
             # TODO: Check role is part of the summary already
-            role_exists = self.db.simple_select_one_onecol_txn(
+            role_exists = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="group_summary_roles",
                 keyvalues={"group_id": group_id, "role_id": role_id},
@@ -872,7 +874,7 @@ class GroupServerStore(GroupServerWorkerStore):
                     (group_id, role_id, group_id, role_id),
                 )
 
-        existing = self.db.simple_select_one_txn(
+        existing = self.db_pool.simple_select_one_txn(
             txn,
             table="group_summary_users",
             keyvalues={"group_id": group_id, "user_id": user_id, "role_id": role_id},
@@ -901,7 +903,7 @@ class GroupServerStore(GroupServerWorkerStore):
                 to_update["user_order"] = order
             if is_public is not None:
                 to_update["is_public"] = is_public
-            self.db.simple_update_txn(
+            self.db_pool.simple_update_txn(
                 txn,
                 table="group_summary_users",
                 keyvalues={
@@ -915,7 +917,7 @@ class GroupServerStore(GroupServerWorkerStore):
             if is_public is None:
                 is_public = True
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="group_summary_users",
                 values={
@@ -931,7 +933,7 @@ class GroupServerStore(GroupServerWorkerStore):
         if role_id is None:
             role_id = _DEFAULT_ROLE_ID
 
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             table="group_summary_users",
             keyvalues={"group_id": group_id, "role_id": role_id, "user_id": user_id},
             desc="remove_user_from_summary",
@@ -940,7 +942,7 @@ class GroupServerStore(GroupServerWorkerStore):
     def add_group_invite(self, group_id, user_id):
         """Record that the group server has invited a user
         """
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="group_invites",
             values={"group_id": group_id, "user_id": user_id},
             desc="add_group_invite",
@@ -970,7 +972,7 @@ class GroupServerStore(GroupServerWorkerStore):
         """
 
         def _add_user_to_group_txn(txn):
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="group_users",
                 values={
@@ -981,14 +983,14 @@ class GroupServerStore(GroupServerWorkerStore):
                 },
             )
 
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_invites",
                 keyvalues={"group_id": group_id, "user_id": user_id},
             )
 
             if local_attestation:
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     table="group_attestations_renewals",
                     values={
@@ -998,7 +1000,7 @@ class GroupServerStore(GroupServerWorkerStore):
                     },
                 )
             if remote_attestation:
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     table="group_attestations_remote",
                     values={
@@ -1009,49 +1011,49 @@ class GroupServerStore(GroupServerWorkerStore):
                     },
                 )
 
-        return self.db.runInteraction("add_user_to_group", _add_user_to_group_txn)
+        return self.db_pool.runInteraction("add_user_to_group", _add_user_to_group_txn)
 
     def remove_user_from_group(self, group_id, user_id):
         def _remove_user_from_group_txn(txn):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_users",
                 keyvalues={"group_id": group_id, "user_id": user_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_invites",
                 keyvalues={"group_id": group_id, "user_id": user_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_attestations_renewals",
                 keyvalues={"group_id": group_id, "user_id": user_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_attestations_remote",
                 keyvalues={"group_id": group_id, "user_id": user_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_summary_users",
                 keyvalues={"group_id": group_id, "user_id": user_id},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "remove_user_from_group", _remove_user_from_group_txn
         )
 
     def add_room_to_group(self, group_id, room_id, is_public):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="group_rooms",
             values={"group_id": group_id, "room_id": room_id, "is_public": is_public},
             desc="add_room_to_group",
         )
 
     def update_room_in_group_visibility(self, group_id, room_id, is_public):
-        return self.db.simple_update(
+        return self.db_pool.simple_update(
             table="group_rooms",
             keyvalues={"group_id": group_id, "room_id": room_id},
             updatevalues={"is_public": is_public},
@@ -1060,26 +1062,26 @@ class GroupServerStore(GroupServerWorkerStore):
 
     def remove_room_from_group(self, group_id, room_id):
         def _remove_room_from_group_txn(txn):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_rooms",
                 keyvalues={"group_id": group_id, "room_id": room_id},
             )
 
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="group_summary_rooms",
                 keyvalues={"group_id": group_id, "room_id": room_id},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "remove_room_from_group", _remove_room_from_group_txn
         )
 
     def update_group_publicity(self, group_id, user_id, publicise):
         """Update whether the user is publicising their membership of the group
         """
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="local_group_membership",
             keyvalues={"group_id": group_id, "user_id": user_id},
             updatevalues={"is_publicised": publicise},
@@ -1115,12 +1117,12 @@ class GroupServerStore(GroupServerWorkerStore):
 
         def _register_user_group_membership_txn(txn, next_id):
             # TODO: Upsert?
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="local_group_membership",
                 keyvalues={"group_id": group_id, "user_id": user_id},
             )
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="local_group_membership",
                 values={
@@ -1133,7 +1135,7 @@ class GroupServerStore(GroupServerWorkerStore):
                 },
             )
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="local_group_updates",
                 values={
@@ -1152,7 +1154,7 @@ class GroupServerStore(GroupServerWorkerStore):
 
             if membership == "join":
                 if local_attestation:
-                    self.db.simple_insert_txn(
+                    self.db_pool.simple_insert_txn(
                         txn,
                         table="group_attestations_renewals",
                         values={
@@ -1162,7 +1164,7 @@ class GroupServerStore(GroupServerWorkerStore):
                         },
                     )
                 if remote_attestation:
-                    self.db.simple_insert_txn(
+                    self.db_pool.simple_insert_txn(
                         txn,
                         table="group_attestations_remote",
                         values={
@@ -1173,12 +1175,12 @@ class GroupServerStore(GroupServerWorkerStore):
                         },
                     )
             else:
-                self.db.simple_delete_txn(
+                self.db_pool.simple_delete_txn(
                     txn,
                     table="group_attestations_renewals",
                     keyvalues={"group_id": group_id, "user_id": user_id},
                 )
-                self.db.simple_delete_txn(
+                self.db_pool.simple_delete_txn(
                     txn,
                     table="group_attestations_remote",
                     keyvalues={"group_id": group_id, "user_id": user_id},
@@ -1187,7 +1189,7 @@ class GroupServerStore(GroupServerWorkerStore):
             return next_id
 
         with self._group_updates_id_gen.get_next() as next_id:
-            res = yield self.db.runInteraction(
+            res = yield self.db_pool.runInteraction(
                 "register_user_group_membership",
                 _register_user_group_membership_txn,
                 next_id,
@@ -1198,7 +1200,7 @@ class GroupServerStore(GroupServerWorkerStore):
     def create_group(
         self, group_id, user_id, name, avatar_url, short_description, long_description
     ):
-        yield self.db.simple_insert(
+        yield self.db_pool.simple_insert(
             table="groups",
             values={
                 "group_id": group_id,
@@ -1213,7 +1215,7 @@ class GroupServerStore(GroupServerWorkerStore):
 
     @defer.inlineCallbacks
     def update_group_profile(self, group_id, profile):
-        yield self.db.simple_update_one(
+        yield self.db_pool.simple_update_one(
             table="groups",
             keyvalues={"group_id": group_id},
             updatevalues=profile,
@@ -1223,7 +1225,7 @@ class GroupServerStore(GroupServerWorkerStore):
     def update_attestation_renewal(self, group_id, user_id, attestation):
         """Update an attestation that we have renewed
         """
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="group_attestations_renewals",
             keyvalues={"group_id": group_id, "user_id": user_id},
             updatevalues={"valid_until_ms": attestation["valid_until_ms"]},
@@ -1233,7 +1235,7 @@ class GroupServerStore(GroupServerWorkerStore):
     def update_remote_attestion(self, group_id, user_id, attestation):
         """Update an attestation that a remote has renewed
         """
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="group_attestations_remote",
             keyvalues={"group_id": group_id, "user_id": user_id},
             updatevalues={
@@ -1252,7 +1254,7 @@ class GroupServerStore(GroupServerWorkerStore):
             group_id (str)
             user_id (str)
         """
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             table="group_attestations_renewals",
             keyvalues={"group_id": group_id, "user_id": user_id},
             desc="remove_attestation_renewal",
@@ -1288,8 +1290,8 @@ class GroupServerStore(GroupServerWorkerStore):
             ]
 
             for table in tables:
-                self.db.simple_delete_txn(
+                self.db_pool.simple_delete_txn(
                     txn, table=table, keyvalues={"group_id": group_id}
                 )
 
-        return self.db.runInteraction("delete_group", _delete_group_txn)
+        return self.db_pool.runInteraction("delete_group", _delete_group_txn)
diff --git a/synapse/storage/data_stores/main/keys.py b/synapse/storage/databases/main/keys.py
index 4e1642a27a..384e9c5eb0 100644
--- a/synapse/storage/data_stores/main/keys.py
+++ b/synapse/storage/databases/main/keys.py
@@ -86,7 +86,7 @@ class KeyStore(SQLBaseStore):
                 _get_keys(txn, batch)
             return keys
 
-        return self.db.runInteraction("get_server_verify_keys", _txn)
+        return self.db_pool.runInteraction("get_server_verify_keys", _txn)
 
     def store_server_verify_keys(self, from_server, ts_added_ms, verify_keys):
         """Stores NACL verification keys for remote servers.
@@ -121,9 +121,9 @@ class KeyStore(SQLBaseStore):
                 f((i,))
             return res
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "store_server_verify_keys",
-            self.db.simple_upsert_many_txn,
+            self.db_pool.simple_upsert_many_txn,
             table="server_signature_keys",
             key_names=("server_name", "key_id"),
             key_values=key_values,
@@ -151,7 +151,7 @@ class KeyStore(SQLBaseStore):
             ts_valid_until_ms (int): The time when this json stops being valid.
             key_json (bytes): The encoded JSON.
         """
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="server_keys_json",
             keyvalues={
                 "server_name": server_name,
@@ -190,7 +190,7 @@ class KeyStore(SQLBaseStore):
                     keyvalues["key_id"] = key_id
                 if from_server is not None:
                     keyvalues["from_server"] = from_server
-                rows = self.db.simple_select_list_txn(
+                rows = self.db_pool.simple_select_list_txn(
                     txn,
                     "server_keys_json",
                     keyvalues=keyvalues,
@@ -205,4 +205,6 @@ class KeyStore(SQLBaseStore):
                 results[(server_name, key_id, from_server)] = rows
             return results
 
-        return self.db.runInteraction("get_server_keys_json", _get_server_keys_json_txn)
+        return self.db_pool.runInteraction(
+            "get_server_keys_json", _get_server_keys_json_txn
+        )
diff --git a/synapse/storage/data_stores/main/media_repository.py b/synapse/storage/databases/main/media_repository.py
index 15bc13cbd0..80fc1cd009 100644
--- a/synapse/storage/data_stores/main/media_repository.py
+++ b/synapse/storage/databases/main/media_repository.py
@@ -13,16 +13,16 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 
 
 class MediaRepositoryBackgroundUpdateStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(MediaRepositoryBackgroundUpdateStore, self).__init__(
             database, db_conn, hs
         )
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             update_name="local_media_repository_url_idx",
             index_name="local_media_repository_url_idx",
             table="local_media_repository",
@@ -34,7 +34,7 @@ class MediaRepositoryBackgroundUpdateStore(SQLBaseStore):
 class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
     """Persistence for attachments and avatars"""
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(MediaRepositoryStore, self).__init__(database, db_conn, hs)
 
     def get_local_media(self, media_id):
@@ -42,7 +42,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         Returns:
             None if the media_id doesn't exist.
         """
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             "local_media_repository",
             {"media_id": media_id},
             (
@@ -67,7 +67,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         user_id,
         url_cache=None,
     ):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             "local_media_repository",
             {
                 "media_id": media_id,
@@ -83,7 +83,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
 
     def mark_local_media_as_safe(self, media_id: str):
         """Mark a local media as safe from quarantining."""
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="local_media_repository",
             keyvalues={"media_id": media_id},
             updatevalues={"safe_from_quarantine": True},
@@ -136,12 +136,12 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
                 )
             )
 
-        return self.db.runInteraction("get_url_cache", get_url_cache_txn)
+        return self.db_pool.runInteraction("get_url_cache", get_url_cache_txn)
 
     def store_url_cache(
         self, url, response_code, etag, expires_ts, og, media_id, download_ts
     ):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             "local_media_repository_url_cache",
             {
                 "url": url,
@@ -156,7 +156,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         )
 
     def get_local_media_thumbnails(self, media_id):
-        return self.db.simple_select_list(
+        return self.db_pool.simple_select_list(
             "local_media_repository_thumbnails",
             {"media_id": media_id},
             (
@@ -178,7 +178,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         thumbnail_method,
         thumbnail_length,
     ):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             "local_media_repository_thumbnails",
             {
                 "media_id": media_id,
@@ -192,7 +192,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         )
 
     def get_cached_remote_media(self, origin, media_id):
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             "remote_media_cache",
             {"media_origin": origin, "media_id": media_id},
             (
@@ -217,7 +217,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         upload_name,
         filesystem_id,
     ):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             "remote_media_cache",
             {
                 "media_origin": origin,
@@ -262,12 +262,12 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
 
             txn.executemany(sql, ((time_ms, media_id) for media_id in local_media))
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "update_cached_last_access_time", update_cache_txn
         )
 
     def get_remote_media_thumbnails(self, origin, media_id):
-        return self.db.simple_select_list(
+        return self.db_pool.simple_select_list(
             "remote_media_cache_thumbnails",
             {"media_origin": origin, "media_id": media_id},
             (
@@ -292,7 +292,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         thumbnail_method,
         thumbnail_length,
     ):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             "remote_media_cache_thumbnails",
             {
                 "media_origin": origin,
@@ -314,24 +314,26 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
             " WHERE last_access_ts < ?"
         )
 
-        return self.db.execute(
-            "get_remote_media_before", self.db.cursor_to_dict, sql, before_ts
+        return self.db_pool.execute(
+            "get_remote_media_before", self.db_pool.cursor_to_dict, sql, before_ts
         )
 
     def delete_remote_media(self, media_origin, media_id):
         def delete_remote_media_txn(txn):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 "remote_media_cache",
                 keyvalues={"media_origin": media_origin, "media_id": media_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 "remote_media_cache_thumbnails",
                 keyvalues={"media_origin": media_origin, "media_id": media_id},
             )
 
-        return self.db.runInteraction("delete_remote_media", delete_remote_media_txn)
+        return self.db_pool.runInteraction(
+            "delete_remote_media", delete_remote_media_txn
+        )
 
     def get_expired_url_cache(self, now_ts):
         sql = (
@@ -345,7 +347,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
             txn.execute(sql, (now_ts,))
             return [row[0] for row in txn]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_expired_url_cache", _get_expired_url_cache_txn
         )
 
@@ -358,7 +360,9 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
         def _delete_url_cache_txn(txn):
             txn.executemany(sql, [(media_id,) for media_id in media_ids])
 
-        return await self.db.runInteraction("delete_url_cache", _delete_url_cache_txn)
+        return await self.db_pool.runInteraction(
+            "delete_url_cache", _delete_url_cache_txn
+        )
 
     def get_url_cache_media_before(self, before_ts):
         sql = (
@@ -372,7 +376,7 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
             txn.execute(sql, (before_ts,))
             return [row[0] for row in txn]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_url_cache_media_before", _get_url_cache_media_before_txn
         )
 
@@ -389,6 +393,6 @@ class MediaRepositoryStore(MediaRepositoryBackgroundUpdateStore):
 
             txn.executemany(sql, [(media_id,) for media_id in media_ids])
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "delete_url_cache_media", _delete_url_cache_media_txn
         )
diff --git a/synapse/storage/data_stores/main/metrics.py b/synapse/storage/databases/main/metrics.py
index dad5bbc602..baa7a5092a 100644
--- a/synapse/storage/data_stores/main/metrics.py
+++ b/synapse/storage/databases/main/metrics.py
@@ -20,10 +20,10 @@ from twisted.internet import defer
 from synapse.metrics import BucketCollector
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.event_push_actions import (
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.event_push_actions import (
     EventPushActionsWorkerStore,
 )
-from synapse.storage.database import Database
 
 
 class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
@@ -31,7 +31,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
     stats and prometheus metrics.
     """
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super().__init__(database, db_conn, hs)
 
         # Collect metrics on the number of forward extremities that exist.
@@ -66,7 +66,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             )
             return txn.fetchall()
 
-        res = await self.db.runInteraction("read_forward_extremities", fetch)
+        res = await self.db_pool.runInteraction("read_forward_extremities", fetch)
         self._current_forward_extremities_amount = Counter([x[0] for x in res])
 
     @defer.inlineCallbacks
@@ -88,7 +88,7 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             (count,) = txn.fetchone()
             return count
 
-        ret = yield self.db.runInteraction("count_messages", _count_messages)
+        ret = yield self.db_pool.runInteraction("count_messages", _count_messages)
         return ret
 
     @defer.inlineCallbacks
@@ -109,7 +109,9 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             (count,) = txn.fetchone()
             return count
 
-        ret = yield self.db.runInteraction("count_daily_sent_messages", _count_messages)
+        ret = yield self.db_pool.runInteraction(
+            "count_daily_sent_messages", _count_messages
+        )
         return ret
 
     @defer.inlineCallbacks
@@ -124,5 +126,5 @@ class ServerMetricsStore(EventPushActionsWorkerStore, SQLBaseStore):
             (count,) = txn.fetchone()
             return count
 
-        ret = yield self.db.runInteraction("count_daily_active_rooms", _count)
+        ret = yield self.db_pool.runInteraction("count_daily_active_rooms", _count)
         return ret
diff --git a/synapse/storage/data_stores/main/monthly_active_users.py b/synapse/storage/databases/main/monthly_active_users.py
index e459cf49a0..02b01d9619 100644
--- a/synapse/storage/data_stores/main/monthly_active_users.py
+++ b/synapse/storage/databases/main/monthly_active_users.py
@@ -18,7 +18,7 @@ from typing import List
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database, make_in_list_sql_clause
+from synapse.storage.database import DatabasePool, make_in_list_sql_clause
 from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
@@ -29,7 +29,7 @@ LAST_SEEN_GRANULARITY = 60 * 60 * 1000
 
 
 class MonthlyActiveUsersWorkerStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(MonthlyActiveUsersWorkerStore, self).__init__(database, db_conn, hs)
         self._clock = hs.get_clock()
         self.hs = hs
@@ -48,7 +48,7 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
             (count,) = txn.fetchone()
             return count
 
-        return self.db.runInteraction("count_users", _count_users)
+        return self.db_pool.runInteraction("count_users", _count_users)
 
     @cached(num_args=0)
     def get_monthly_active_count_by_service(self):
@@ -76,7 +76,9 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
             result = txn.fetchall()
             return dict(result)
 
-        return self.db.runInteraction("count_users_by_service", _count_users_by_service)
+        return self.db_pool.runInteraction(
+            "count_users_by_service", _count_users_by_service
+        )
 
     async def get_registered_reserved_users(self) -> List[str]:
         """Of the reserved threepids defined in config, retrieve those that are associated
@@ -109,7 +111,7 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
 
         """
 
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="monthly_active_users",
             keyvalues={"user_id": user_id},
             retcol="timestamp",
@@ -119,7 +121,7 @@ class MonthlyActiveUsersWorkerStore(SQLBaseStore):
 
 
 class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(MonthlyActiveUsersStore, self).__init__(database, db_conn, hs)
 
         self._limit_usage_by_mau = hs.config.limit_usage_by_mau
@@ -128,7 +130,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
 
         # Do not add more reserved users than the total allowable number
         # cur = LoggingTransaction(
-        self.db.new_transaction(
+        self.db_pool.new_transaction(
             db_conn,
             "initialise_mau_threepids",
             [],
@@ -162,7 +164,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
                 is_support = self.is_support_user_txn(txn, user_id)
                 if not is_support:
                     # We do this manually here to avoid hitting #6791
-                    self.db.simple_upsert_txn(
+                    self.db_pool.simple_upsert_txn(
                         txn,
                         table="monthly_active_users",
                         keyvalues={"user_id": user_id},
@@ -246,7 +248,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
             self._invalidate_cache_and_stream(txn, self.get_monthly_active_count, ())
 
         reserved_users = await self.get_registered_reserved_users()
-        await self.db.runInteraction(
+        await self.db_pool.runInteraction(
             "reap_monthly_active_users", _reap_users, reserved_users
         )
 
@@ -273,7 +275,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
         if is_support:
             return
 
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "upsert_monthly_active_user", self.upsert_monthly_active_user_txn, user_id
         )
 
@@ -303,7 +305,7 @@ class MonthlyActiveUsersStore(MonthlyActiveUsersWorkerStore):
         # never be a big table and alternative approaches (batching multiple
         # upserts into a single txn) introduced a lot of extra complexity.
         # See https://github.com/matrix-org/synapse/issues/3854 for more
-        is_insert = self.db.simple_upsert_txn(
+        is_insert = self.db_pool.simple_upsert_txn(
             txn,
             table="monthly_active_users",
             keyvalues={"user_id": user_id},
diff --git a/synapse/storage/data_stores/main/openid.py b/synapse/storage/databases/main/openid.py
index cc21437e92..dcd1ff911a 100644
--- a/synapse/storage/data_stores/main/openid.py
+++ b/synapse/storage/databases/main/openid.py
@@ -3,7 +3,7 @@ from synapse.storage._base import SQLBaseStore
 
 class OpenIdStore(SQLBaseStore):
     def insert_open_id_token(self, token, ts_valid_until_ms, user_id):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="open_id_tokens",
             values={
                 "token": token,
@@ -28,6 +28,6 @@ class OpenIdStore(SQLBaseStore):
             else:
                 return rows[0][0]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_user_id_for_token", get_user_id_for_token_txn
         )
diff --git a/synapse/storage/data_stores/main/presence.py b/synapse/storage/databases/main/presence.py
index 7574612619..99e66dc6e9 100644
--- a/synapse/storage/data_stores/main/presence.py
+++ b/synapse/storage/databases/main/presence.py
@@ -31,7 +31,7 @@ class PresenceStore(SQLBaseStore):
         )
 
         with stream_ordering_manager as stream_orderings:
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "update_presence",
                 self._update_presence_txn,
                 stream_orderings,
@@ -48,7 +48,7 @@ class PresenceStore(SQLBaseStore):
             txn.call_after(self._get_presence_for_user.invalidate, (state.user_id,))
 
         # Actually insert new rows
-        self.db.simple_insert_many_txn(
+        self.db_pool.simple_insert_many_txn(
             txn,
             table="presence_stream",
             values=[
@@ -124,7 +124,7 @@ class PresenceStore(SQLBaseStore):
 
             return updates, upper_bound, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_presence_updates", get_all_presence_updates_txn
         )
 
@@ -139,7 +139,7 @@ class PresenceStore(SQLBaseStore):
         inlineCallbacks=True,
     )
     def get_presence_for_users(self, user_ids):
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="presence_stream",
             column="user_id",
             iterable=user_ids,
@@ -165,7 +165,7 @@ class PresenceStore(SQLBaseStore):
         return self._presence_id_gen.get_current_token()
 
     def allow_presence_visible(self, observed_localpart, observer_userid):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="presence_allow_inbound",
             values={
                 "observed_user_id": observed_localpart,
@@ -176,7 +176,7 @@ class PresenceStore(SQLBaseStore):
         )
 
     def disallow_presence_visible(self, observed_localpart, observer_userid):
-        return self.db.simple_delete_one(
+        return self.db_pool.simple_delete_one(
             table="presence_allow_inbound",
             keyvalues={
                 "observed_user_id": observed_localpart,
diff --git a/synapse/storage/data_stores/main/profile.py b/synapse/storage/databases/main/profile.py
index bfc9369f0b..4a4f2cb385 100644
--- a/synapse/storage/data_stores/main/profile.py
+++ b/synapse/storage/databases/main/profile.py
@@ -17,14 +17,14 @@ from twisted.internet import defer
 
 from synapse.api.errors import StoreError
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.roommember import ProfileInfo
+from synapse.storage.databases.main.roommember import ProfileInfo
 
 
 class ProfileWorkerStore(SQLBaseStore):
     @defer.inlineCallbacks
     def get_profileinfo(self, user_localpart):
         try:
-            profile = yield self.db.simple_select_one(
+            profile = yield self.db_pool.simple_select_one(
                 table="profiles",
                 keyvalues={"user_id": user_localpart},
                 retcols=("displayname", "avatar_url"),
@@ -42,7 +42,7 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     def get_profile_displayname(self, user_localpart):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="profiles",
             keyvalues={"user_id": user_localpart},
             retcol="displayname",
@@ -50,7 +50,7 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     def get_profile_avatar_url(self, user_localpart):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="profiles",
             keyvalues={"user_id": user_localpart},
             retcol="avatar_url",
@@ -58,7 +58,7 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     def get_from_remote_profile_cache(self, user_id):
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             table="remote_profile_cache",
             keyvalues={"user_id": user_id},
             retcols=("displayname", "avatar_url"),
@@ -67,12 +67,12 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     def create_profile(self, user_localpart):
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="profiles", values={"user_id": user_localpart}, desc="create_profile"
         )
 
     def set_profile_displayname(self, user_localpart, new_displayname):
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="profiles",
             keyvalues={"user_id": user_localpart},
             updatevalues={"displayname": new_displayname},
@@ -80,7 +80,7 @@ class ProfileWorkerStore(SQLBaseStore):
         )
 
     def set_profile_avatar_url(self, user_localpart, new_avatar_url):
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="profiles",
             keyvalues={"user_id": user_localpart},
             updatevalues={"avatar_url": new_avatar_url},
@@ -95,7 +95,7 @@ class ProfileStore(ProfileWorkerStore):
         This should only be called when `is_subscribed_remote_profile_for_user`
         would return true for the user.
         """
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="remote_profile_cache",
             keyvalues={"user_id": user_id},
             values={
@@ -107,7 +107,7 @@ class ProfileStore(ProfileWorkerStore):
         )
 
     def update_remote_profile_cache(self, user_id, displayname, avatar_url):
-        return self.db.simple_update(
+        return self.db_pool.simple_update(
             table="remote_profile_cache",
             keyvalues={"user_id": user_id},
             updatevalues={
@@ -125,7 +125,7 @@ class ProfileStore(ProfileWorkerStore):
         """
         subscribed = yield self.is_subscribed_remote_profile_for_user(user_id)
         if not subscribed:
-            yield self.db.simple_delete(
+            yield self.db_pool.simple_delete(
                 table="remote_profile_cache",
                 keyvalues={"user_id": user_id},
                 desc="delete_remote_profile_cache",
@@ -144,9 +144,9 @@ class ProfileStore(ProfileWorkerStore):
 
             txn.execute(sql, (last_checked,))
 
-            return self.db.cursor_to_dict(txn)
+            return self.db_pool.cursor_to_dict(txn)
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_remote_profile_cache_entries_that_expire",
             _get_remote_profile_cache_entries_that_expire_txn,
         )
@@ -155,7 +155,7 @@ class ProfileStore(ProfileWorkerStore):
     def is_subscribed_remote_profile_for_user(self, user_id):
         """Check whether we are interested in a remote user's profile.
         """
-        res = yield self.db.simple_select_one_onecol(
+        res = yield self.db_pool.simple_select_one_onecol(
             table="group_users",
             keyvalues={"user_id": user_id},
             retcol="user_id",
@@ -166,7 +166,7 @@ class ProfileStore(ProfileWorkerStore):
         if res:
             return True
 
-        res = yield self.db.simple_select_one_onecol(
+        res = yield self.db_pool.simple_select_one_onecol(
             table="group_invites",
             keyvalues={"user_id": user_id},
             retcol="user_id",
diff --git a/synapse/storage/data_stores/main/purge_events.py b/synapse/storage/databases/main/purge_events.py
index b53fe35c33..3526b6fd66 100644
--- a/synapse/storage/data_stores/main/purge_events.py
+++ b/synapse/storage/databases/main/purge_events.py
@@ -18,7 +18,7 @@ from typing import Any, Tuple
 
 from synapse.api.errors import SynapseError
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.state import StateGroupWorkerStore
+from synapse.storage.databases.main.state import StateGroupWorkerStore
 from synapse.types import RoomStreamToken
 
 logger = logging.getLogger(__name__)
@@ -43,7 +43,7 @@ class PurgeEventsStore(StateGroupWorkerStore, SQLBaseStore):
             deleted events.
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "purge_history",
             self._purge_history_txn,
             room_id,
@@ -293,7 +293,7 @@ class PurgeEventsStore(StateGroupWorkerStore, SQLBaseStore):
             Deferred[List[int]]: The list of state groups to delete.
         """
 
-        return self.db.runInteraction("purge_room", self._purge_room_txn, room_id)
+        return self.db_pool.runInteraction("purge_room", self._purge_room_txn, room_id)
 
     def _purge_room_txn(self, txn, room_id):
         # First we fetch all the state groups that should be deleted, before
diff --git a/synapse/storage/data_stores/main/push_rule.py b/synapse/storage/databases/main/push_rule.py
index c229248101..97cc12931d 100644
--- a/synapse/storage/data_stores/main/push_rule.py
+++ b/synapse/storage/databases/main/push_rule.py
@@ -25,12 +25,12 @@ from twisted.internet import defer
 from synapse.push.baserules import list_with_base_rules
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
 from synapse.storage._base import SQLBaseStore, db_to_json
-from synapse.storage.data_stores.main.appservice import ApplicationServiceWorkerStore
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.data_stores.main.pusher import PusherWorkerStore
-from synapse.storage.data_stores.main.receipts import ReceiptsWorkerStore
-from synapse.storage.data_stores.main.roommember import RoomMemberWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.appservice import ApplicationServiceWorkerStore
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
+from synapse.storage.databases.main.pusher import PusherWorkerStore
+from synapse.storage.databases.main.receipts import ReceiptsWorkerStore
+from synapse.storage.databases.main.roommember import RoomMemberWorkerStore
 from synapse.storage.push_rule import InconsistentRuleException, RuleNotFoundException
 from synapse.storage.util.id_generators import ChainedIdGenerator
 from synapse.util.caches.descriptors import cachedInlineCallbacks, cachedList
@@ -79,7 +79,7 @@ class PushRulesWorkerStore(
     # the abstract methods being implemented.
     __metaclass__ = abc.ABCMeta
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(PushRulesWorkerStore, self).__init__(database, db_conn, hs)
 
         if hs.config.worker.worker_app is None:
@@ -91,7 +91,7 @@ class PushRulesWorkerStore(
                 db_conn, "push_rules_stream", "stream_id"
             )
 
-        push_rules_prefill, push_rules_id = self.db.get_cache_dict(
+        push_rules_prefill, push_rules_id = self.db_pool.get_cache_dict(
             db_conn,
             "push_rules_stream",
             entity_column="user_id",
@@ -116,7 +116,7 @@ class PushRulesWorkerStore(
 
     @cachedInlineCallbacks(max_entries=5000)
     def get_push_rules_for_user(self, user_id):
-        rows = yield self.db.simple_select_list(
+        rows = yield self.db_pool.simple_select_list(
             table="push_rules",
             keyvalues={"user_name": user_id},
             retcols=(
@@ -140,7 +140,7 @@ class PushRulesWorkerStore(
 
     @cachedInlineCallbacks(max_entries=5000)
     def get_push_rules_enabled_for_user(self, user_id):
-        results = yield self.db.simple_select_list(
+        results = yield self.db_pool.simple_select_list(
             table="push_rules_enable",
             keyvalues={"user_name": user_id},
             retcols=("user_name", "rule_id", "enabled"),
@@ -162,7 +162,7 @@ class PushRulesWorkerStore(
                 (count,) = txn.fetchone()
                 return bool(count)
 
-            return self.db.runInteraction(
+            return self.db_pool.runInteraction(
                 "have_push_rules_changed", have_push_rules_changed_txn
             )
 
@@ -178,7 +178,7 @@ class PushRulesWorkerStore(
 
         results = {user_id: [] for user_id in user_ids}
 
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="push_rules",
             column="user_name",
             iterable=user_ids,
@@ -336,7 +336,7 @@ class PushRulesWorkerStore(
 
         results = {user_id: {} for user_id in user_ids}
 
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="push_rules_enable",
             column="user_name",
             iterable=user_ids,
@@ -394,7 +394,7 @@ class PushRulesWorkerStore(
 
             return updates, upper_bound, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_push_rule_updates", get_all_push_rule_updates_txn
         )
 
@@ -416,7 +416,7 @@ class PushRuleStore(PushRulesWorkerStore):
         with self._push_rules_stream_id_gen.get_next() as ids:
             stream_id, event_stream_ordering = ids
             if before or after:
-                yield self.db.runInteraction(
+                yield self.db_pool.runInteraction(
                     "_add_push_rule_relative_txn",
                     self._add_push_rule_relative_txn,
                     stream_id,
@@ -430,7 +430,7 @@ class PushRuleStore(PushRulesWorkerStore):
                     after,
                 )
             else:
-                yield self.db.runInteraction(
+                yield self.db_pool.runInteraction(
                     "_add_push_rule_highest_priority_txn",
                     self._add_push_rule_highest_priority_txn,
                     stream_id,
@@ -461,7 +461,7 @@ class PushRuleStore(PushRulesWorkerStore):
 
         relative_to_rule = before or after
 
-        res = self.db.simple_select_one_txn(
+        res = self.db_pool.simple_select_one_txn(
             txn,
             table="push_rules",
             keyvalues={"user_name": user_id, "rule_id": relative_to_rule},
@@ -584,7 +584,7 @@ class PushRuleStore(PushRulesWorkerStore):
             # We didn't update a row with the given rule_id so insert one
             push_rule_id = self._push_rule_id_gen.get_next()
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="push_rules",
                 values={
@@ -627,7 +627,7 @@ class PushRuleStore(PushRulesWorkerStore):
         """
 
         def delete_push_rule_txn(txn, stream_id, event_stream_ordering):
-            self.db.simple_delete_one_txn(
+            self.db_pool.simple_delete_one_txn(
                 txn, "push_rules", {"user_name": user_id, "rule_id": rule_id}
             )
 
@@ -637,7 +637,7 @@ class PushRuleStore(PushRulesWorkerStore):
 
         with self._push_rules_stream_id_gen.get_next() as ids:
             stream_id, event_stream_ordering = ids
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "delete_push_rule",
                 delete_push_rule_txn,
                 stream_id,
@@ -648,7 +648,7 @@ class PushRuleStore(PushRulesWorkerStore):
     def set_push_rule_enabled(self, user_id, rule_id, enabled):
         with self._push_rules_stream_id_gen.get_next() as ids:
             stream_id, event_stream_ordering = ids
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "_set_push_rule_enabled_txn",
                 self._set_push_rule_enabled_txn,
                 stream_id,
@@ -662,7 +662,7 @@ class PushRuleStore(PushRulesWorkerStore):
         self, txn, stream_id, event_stream_ordering, user_id, rule_id, enabled
     ):
         new_id = self._push_rules_enable_id_gen.get_next()
-        self.db.simple_upsert_txn(
+        self.db_pool.simple_upsert_txn(
             txn,
             "push_rules_enable",
             {"user_name": user_id, "rule_id": rule_id},
@@ -702,7 +702,7 @@ class PushRuleStore(PushRulesWorkerStore):
                     update_stream=False,
                 )
             else:
-                self.db.simple_update_one_txn(
+                self.db_pool.simple_update_one_txn(
                     txn,
                     "push_rules",
                     {"user_name": user_id, "rule_id": rule_id},
@@ -721,7 +721,7 @@ class PushRuleStore(PushRulesWorkerStore):
 
         with self._push_rules_stream_id_gen.get_next() as ids:
             stream_id, event_stream_ordering = ids
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "set_push_rule_actions",
                 set_push_rule_actions_txn,
                 stream_id,
@@ -741,7 +741,7 @@ class PushRuleStore(PushRulesWorkerStore):
         if data is not None:
             values.update(data)
 
-        self.db.simple_insert_txn(txn, "push_rules_stream", values=values)
+        self.db_pool.simple_insert_txn(txn, "push_rules_stream", values=values)
 
         txn.call_after(self.get_push_rules_for_user.invalidate, (user_id,))
         txn.call_after(self.get_push_rules_enabled_for_user.invalidate, (user_id,))
diff --git a/synapse/storage/data_stores/main/pusher.py b/synapse/storage/databases/main/pusher.py
index e18f1ca87c..b5200fbe79 100644
--- a/synapse/storage/data_stores/main/pusher.py
+++ b/synapse/storage/databases/main/pusher.py
@@ -50,7 +50,7 @@ class PusherWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def user_has_pusher(self, user_id):
-        ret = yield self.db.simple_select_one_onecol(
+        ret = yield self.db_pool.simple_select_one_onecol(
             "pushers", {"user_name": user_id}, "id", allow_none=True
         )
         return ret is not None
@@ -63,7 +63,7 @@ class PusherWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def get_pushers_by(self, keyvalues):
-        ret = yield self.db.simple_select_list(
+        ret = yield self.db_pool.simple_select_list(
             "pushers",
             keyvalues,
             [
@@ -91,11 +91,11 @@ class PusherWorkerStore(SQLBaseStore):
     def get_all_pushers(self):
         def get_pushers(txn):
             txn.execute("SELECT * FROM pushers")
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
 
             return self._decode_pushers_rows(rows)
 
-        rows = yield self.db.runInteraction("get_all_pushers", get_pushers)
+        rows = yield self.db_pool.runInteraction("get_all_pushers", get_pushers)
         return rows
 
     async def get_all_updated_pushers_rows(
@@ -160,7 +160,7 @@ class PusherWorkerStore(SQLBaseStore):
 
             return updates, upper_bound, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_updated_pushers_rows", get_all_updated_pushers_rows_txn
         )
 
@@ -176,7 +176,7 @@ class PusherWorkerStore(SQLBaseStore):
         inlineCallbacks=True,
     )
     def get_if_users_have_pushers(self, user_ids):
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="pushers",
             column="user_name",
             iterable=user_ids,
@@ -193,7 +193,7 @@ class PusherWorkerStore(SQLBaseStore):
     def update_pusher_last_stream_ordering(
         self, app_id, pushkey, user_id, last_stream_ordering
     ):
-        yield self.db.simple_update_one(
+        yield self.db_pool.simple_update_one(
             "pushers",
             {"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
             {"last_stream_ordering": last_stream_ordering},
@@ -216,7 +216,7 @@ class PusherWorkerStore(SQLBaseStore):
         Returns:
             Deferred[bool]: True if the pusher still exists; False if it has been deleted.
         """
-        updated = yield self.db.simple_update(
+        updated = yield self.db_pool.simple_update(
             table="pushers",
             keyvalues={"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
             updatevalues={
@@ -230,7 +230,7 @@ class PusherWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def update_pusher_failing_since(self, app_id, pushkey, user_id, failing_since):
-        yield self.db.simple_update(
+        yield self.db_pool.simple_update(
             table="pushers",
             keyvalues={"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
             updatevalues={"failing_since": failing_since},
@@ -239,7 +239,7 @@ class PusherWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def get_throttle_params_by_room(self, pusher_id):
-        res = yield self.db.simple_select_list(
+        res = yield self.db_pool.simple_select_list(
             "pusher_throttle",
             {"pusher": pusher_id},
             ["room_id", "last_sent_ts", "throttle_ms"],
@@ -259,7 +259,7 @@ class PusherWorkerStore(SQLBaseStore):
     def set_throttle_params(self, pusher_id, room_id, params):
         # no need to lock because `pusher_throttle` has a primary key on
         # (pusher, room_id) so simple_upsert will retry
-        yield self.db.simple_upsert(
+        yield self.db_pool.simple_upsert(
             "pusher_throttle",
             {"pusher": pusher_id, "room_id": room_id},
             params,
@@ -291,7 +291,7 @@ class PusherStore(PusherWorkerStore):
         with self._pushers_id_gen.get_next() as stream_id:
             # no need to lock because `pushers` has a unique key on
             # (app_id, pushkey, user_name) so simple_upsert will retry
-            yield self.db.simple_upsert(
+            yield self.db_pool.simple_upsert(
                 table="pushers",
                 keyvalues={"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
                 values={
@@ -316,7 +316,7 @@ class PusherStore(PusherWorkerStore):
 
             if user_has_pusher is not True:
                 # invalidate, since we the user might not have had a pusher before
-                yield self.db.runInteraction(
+                yield self.db_pool.runInteraction(
                     "add_pusher",
                     self._invalidate_cache_and_stream,
                     self.get_if_user_has_pusher,
@@ -330,7 +330,7 @@ class PusherStore(PusherWorkerStore):
                 txn, self.get_if_user_has_pusher, (user_id,)
             )
 
-            self.db.simple_delete_one_txn(
+            self.db_pool.simple_delete_one_txn(
                 txn,
                 "pushers",
                 {"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
@@ -339,7 +339,7 @@ class PusherStore(PusherWorkerStore):
             # it's possible for us to end up with duplicate rows for
             # (app_id, pushkey, user_id) at different stream_ids, but that
             # doesn't really matter.
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="deleted_pushers",
                 values={
@@ -351,4 +351,6 @@ class PusherStore(PusherWorkerStore):
             )
 
         with self._pushers_id_gen.get_next() as stream_id:
-            yield self.db.runInteraction("delete_pusher", delete_pusher_txn, stream_id)
+            yield self.db_pool.runInteraction(
+                "delete_pusher", delete_pusher_txn, stream_id
+            )
diff --git a/synapse/storage/data_stores/main/receipts.py b/synapse/storage/databases/main/receipts.py
index 1d723f2d34..6255977c92 100644
--- a/synapse/storage/data_stores/main/receipts.py
+++ b/synapse/storage/databases/main/receipts.py
@@ -23,7 +23,7 @@ from canonicaljson import json
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.util.id_generators import StreamIdGenerator
 from synapse.util.async_helpers import ObservableDeferred
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
@@ -41,7 +41,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
     # the abstract methods being implemented.
     __metaclass__ = abc.ABCMeta
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(ReceiptsWorkerStore, self).__init__(database, db_conn, hs)
 
         self._receipts_stream_cache = StreamChangeCache(
@@ -64,7 +64,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
     @cached(num_args=2)
     def get_receipts_for_room(self, room_id, receipt_type):
-        return self.db.simple_select_list(
+        return self.db_pool.simple_select_list(
             table="receipts_linearized",
             keyvalues={"room_id": room_id, "receipt_type": receipt_type},
             retcols=("user_id", "event_id"),
@@ -73,7 +73,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
     @cached(num_args=3)
     def get_last_receipt_event_id_for_user(self, user_id, room_id, receipt_type):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="receipts_linearized",
             keyvalues={
                 "room_id": room_id,
@@ -87,7 +87,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
     @cachedInlineCallbacks(num_args=2)
     def get_receipts_for_user(self, user_id, receipt_type):
-        rows = yield self.db.simple_select_list(
+        rows = yield self.db_pool.simple_select_list(
             table="receipts_linearized",
             keyvalues={"user_id": user_id, "receipt_type": receipt_type},
             retcols=("room_id", "event_id"),
@@ -111,7 +111,9 @@ class ReceiptsWorkerStore(SQLBaseStore):
             txn.execute(sql, (user_id,))
             return txn.fetchall()
 
-        rows = yield self.db.runInteraction("get_receipts_for_user_with_orderings", f)
+        rows = yield self.db_pool.runInteraction(
+            "get_receipts_for_user_with_orderings", f
+        )
         return {
             row[0]: {
                 "event_id": row[1],
@@ -190,11 +192,11 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
                 txn.execute(sql, (room_id, to_key))
 
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
 
             return rows
 
-        rows = yield self.db.runInteraction("get_linearized_receipts_for_room", f)
+        rows = yield self.db_pool.runInteraction("get_linearized_receipts_for_room", f)
 
         if not rows:
             return []
@@ -240,9 +242,9 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
                 txn.execute(sql + clause, [to_key] + list(args))
 
-            return self.db.cursor_to_dict(txn)
+            return self.db_pool.cursor_to_dict(txn)
 
-        txn_results = yield self.db.runInteraction(
+        txn_results = yield self.db_pool.runInteraction(
             "_get_linearized_receipts_for_rooms", f
         )
 
@@ -288,7 +290,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
             return [r[0] for r in txn]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_users_sent_receipts_between", _get_users_sent_receipts_between_txn
         )
 
@@ -340,7 +342,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
             return updates, upper_bound, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_updated_receipts", get_all_updated_receipts_txn
         )
 
@@ -371,7 +373,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
 
 
 class ReceiptsStore(ReceiptsWorkerStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         # We instantiate this first as the ReceiptsWorkerStore constructor
         # needs to be able to call get_max_receipt_stream_id
         self._receipts_id_gen = StreamIdGenerator(
@@ -393,7 +395,7 @@ class ReceiptsStore(ReceiptsWorkerStore):
             otherwise, the rx timestamp of the event that the RR corresponds to
                 (or 0 if the event is unknown)
         """
-        res = self.db.simple_select_one_txn(
+        res = self.db_pool.simple_select_one_txn(
             txn,
             table="events",
             retcols=["stream_ordering", "received_ts"],
@@ -446,7 +448,7 @@ class ReceiptsStore(ReceiptsWorkerStore):
             (user_id, room_id, receipt_type),
         )
 
-        self.db.simple_upsert_txn(
+        self.db_pool.simple_upsert_txn(
             txn,
             table="receipts_linearized",
             keyvalues={
@@ -506,13 +508,13 @@ class ReceiptsStore(ReceiptsWorkerStore):
                 else:
                     raise RuntimeError("Unrecognized event_ids: %r" % (event_ids,))
 
-            linearized_event_id = yield self.db.runInteraction(
+            linearized_event_id = yield self.db_pool.runInteraction(
                 "insert_receipt_conv", graph_to_linear
             )
 
         stream_id_manager = self._receipts_id_gen.get_next()
         with stream_id_manager as stream_id:
-            event_ts = yield self.db.runInteraction(
+            event_ts = yield self.db_pool.runInteraction(
                 "insert_linearized_receipt",
                 self.insert_linearized_receipt_txn,
                 room_id,
@@ -541,7 +543,7 @@ class ReceiptsStore(ReceiptsWorkerStore):
         return stream_id, max_persisted_id
 
     def insert_graph_receipt(self, room_id, receipt_type, user_id, event_ids, data):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "insert_graph_receipt",
             self.insert_graph_receipt_txn,
             room_id,
@@ -567,7 +569,7 @@ class ReceiptsStore(ReceiptsWorkerStore):
             self._get_linearized_receipts_for_room.invalidate_many, (room_id,)
         )
 
-        self.db.simple_delete_txn(
+        self.db_pool.simple_delete_txn(
             txn,
             table="receipts_graph",
             keyvalues={
@@ -576,7 +578,7 @@ class ReceiptsStore(ReceiptsWorkerStore):
                 "user_id": user_id,
             },
         )
-        self.db.simple_insert_txn(
+        self.db_pool.simple_insert_txn(
             txn,
             table="receipts_graph",
             values={
diff --git a/synapse/storage/data_stores/main/registration.py b/synapse/storage/databases/main/registration.py
index 27d2c5028c..f618629e09 100644
--- a/synapse/storage/data_stores/main/registration.py
+++ b/synapse/storage/databases/main/registration.py
@@ -26,7 +26,7 @@ from synapse.api.constants import UserTypes
 from synapse.api.errors import Codes, StoreError, SynapseError, ThreepidValidationError
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.types import Cursor
 from synapse.storage.util.sequence import build_sequence_generator
 from synapse.types import UserID
@@ -38,7 +38,7 @@ logger = logging.getLogger(__name__)
 
 
 class RegistrationWorkerStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RegistrationWorkerStore, self).__init__(database, db_conn, hs)
 
         self.config = hs.config
@@ -50,7 +50,7 @@ class RegistrationWorkerStore(SQLBaseStore):
 
     @cached()
     def get_user_by_id(self, user_id):
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             table="users",
             keyvalues={"name": user_id},
             retcols=[
@@ -101,7 +101,7 @@ class RegistrationWorkerStore(SQLBaseStore):
                 including the keys `name`, `is_guest`, `device_id`, `token_id`,
                 `valid_until_ms`.
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_user_by_access_token", self._query_for_auth, token
         )
 
@@ -116,7 +116,7 @@ class RegistrationWorkerStore(SQLBaseStore):
                 otherwise int representation of the timestamp (as a number of
                 milliseconds since epoch).
         """
-        res = yield self.db.simple_select_one_onecol(
+        res = yield self.db_pool.simple_select_one_onecol(
             table="account_validity",
             keyvalues={"user_id": user_id},
             retcol="expiration_ts_ms",
@@ -144,7 +144,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         """
 
         def set_account_validity_for_user_txn(txn):
-            self.db.simple_update_txn(
+            self.db_pool.simple_update_txn(
                 txn=txn,
                 table="account_validity",
                 keyvalues={"user_id": user_id},
@@ -158,7 +158,7 @@ class RegistrationWorkerStore(SQLBaseStore):
                 txn, self.get_expiration_ts_for_user, (user_id,)
             )
 
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "set_account_validity_for_user", set_account_validity_for_user_txn
         )
 
@@ -174,7 +174,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Raises:
             StoreError: The provided token is already set for another user.
         """
-        yield self.db.simple_update_one(
+        yield self.db_pool.simple_update_one(
             table="account_validity",
             keyvalues={"user_id": user_id},
             updatevalues={"renewal_token": renewal_token},
@@ -191,7 +191,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             defer.Deferred[str]: The ID of the user to which the token belongs.
         """
-        res = yield self.db.simple_select_one_onecol(
+        res = yield self.db_pool.simple_select_one_onecol(
             table="account_validity",
             keyvalues={"renewal_token": renewal_token},
             retcol="user_id",
@@ -210,7 +210,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             defer.Deferred[str]: The renewal token associated with this user ID.
         """
-        res = yield self.db.simple_select_one_onecol(
+        res = yield self.db_pool.simple_select_one_onecol(
             table="account_validity",
             keyvalues={"user_id": user_id},
             retcol="renewal_token",
@@ -236,9 +236,9 @@ class RegistrationWorkerStore(SQLBaseStore):
             )
             values = [False, now_ms, renew_at]
             txn.execute(sql, values)
-            return self.db.cursor_to_dict(txn)
+            return self.db_pool.cursor_to_dict(txn)
 
-        res = yield self.db.runInteraction(
+        res = yield self.db_pool.runInteraction(
             "get_users_expiring_soon",
             select_users_txn,
             self.clock.time_msec(),
@@ -257,7 +257,7 @@ class RegistrationWorkerStore(SQLBaseStore):
             email_sent (bool): Flag which indicates whether a renewal email has been sent
                 to this user.
         """
-        yield self.db.simple_update_one(
+        yield self.db_pool.simple_update_one(
             table="account_validity",
             keyvalues={"user_id": user_id},
             updatevalues={"email_sent": email_sent},
@@ -272,7 +272,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Args:
             user_id (str): ID of the user to remove from the account validity table.
         """
-        yield self.db.simple_delete_one(
+        yield self.db_pool.simple_delete_one(
             table="account_validity",
             keyvalues={"user_id": user_id},
             desc="delete_account_validity_for_user",
@@ -287,7 +287,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns (bool):
             true iff the user is a server admin, false otherwise.
         """
-        res = await self.db.simple_select_one_onecol(
+        res = await self.db_pool.simple_select_one_onecol(
             table="users",
             keyvalues={"name": user.to_string()},
             retcol="admin",
@@ -307,14 +307,14 @@ class RegistrationWorkerStore(SQLBaseStore):
         """
 
         def set_server_admin_txn(txn):
-            self.db.simple_update_one_txn(
+            self.db_pool.simple_update_one_txn(
                 txn, "users", {"name": user.to_string()}, {"admin": 1 if admin else 0}
             )
             self._invalidate_cache_and_stream(
                 txn, self.get_user_by_id, (user.to_string(),)
             )
 
-        return self.db.runInteraction("set_server_admin", set_server_admin_txn)
+        return self.db_pool.runInteraction("set_server_admin", set_server_admin_txn)
 
     def _query_for_auth(self, txn, token):
         sql = (
@@ -326,7 +326,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         )
 
         txn.execute(sql, (token,))
-        rows = self.db.cursor_to_dict(txn)
+        rows = self.db_pool.cursor_to_dict(txn)
         if rows:
             return rows[0]
 
@@ -342,7 +342,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             Deferred[bool]: True if user 'user_type' is null or empty string
         """
-        res = yield self.db.runInteraction(
+        res = yield self.db_pool.runInteraction(
             "is_real_user", self.is_real_user_txn, user_id
         )
         return res
@@ -357,12 +357,12 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             Deferred[bool]: True if user is of type UserTypes.SUPPORT
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "is_support_user", self.is_support_user_txn, user_id
         )
 
     def is_real_user_txn(self, txn, user_id):
-        res = self.db.simple_select_one_onecol_txn(
+        res = self.db_pool.simple_select_one_onecol_txn(
             txn=txn,
             table="users",
             keyvalues={"name": user_id},
@@ -372,7 +372,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         return res is None
 
     def is_support_user_txn(self, txn, user_id):
-        res = self.db.simple_select_one_onecol_txn(
+        res = self.db_pool.simple_select_one_onecol_txn(
             txn=txn,
             table="users",
             keyvalues={"name": user_id},
@@ -391,7 +391,7 @@ class RegistrationWorkerStore(SQLBaseStore):
             txn.execute(sql, (user_id,))
             return dict(txn)
 
-        return self.db.runInteraction("get_users_by_id_case_insensitive", f)
+        return self.db_pool.runInteraction("get_users_by_id_case_insensitive", f)
 
     async def get_user_by_external_id(
         self, auth_provider: str, external_id: str
@@ -405,7 +405,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             str|None: the mxid of the user, or None if they are not known
         """
-        return await self.db.simple_select_one_onecol(
+        return await self.db_pool.simple_select_one_onecol(
             table="user_external_ids",
             keyvalues={"auth_provider": auth_provider, "external_id": external_id},
             retcol="user_id",
@@ -419,12 +419,12 @@ class RegistrationWorkerStore(SQLBaseStore):
 
         def _count_users(txn):
             txn.execute("SELECT COUNT(*) AS users FROM users")
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             if rows:
                 return rows[0]["users"]
             return 0
 
-        ret = yield self.db.runInteraction("count_users", _count_users)
+        ret = yield self.db_pool.runInteraction("count_users", _count_users)
         return ret
 
     def count_daily_user_type(self):
@@ -456,7 +456,9 @@ class RegistrationWorkerStore(SQLBaseStore):
                 results[row[0]] = row[1]
             return results
 
-        return self.db.runInteraction("count_daily_user_type", _count_daily_user_type)
+        return self.db_pool.runInteraction(
+            "count_daily_user_type", _count_daily_user_type
+        )
 
     @defer.inlineCallbacks
     def count_nonbridged_users(self):
@@ -470,7 +472,7 @@ class RegistrationWorkerStore(SQLBaseStore):
             (count,) = txn.fetchone()
             return count
 
-        ret = yield self.db.runInteraction("count_users", _count_users)
+        ret = yield self.db_pool.runInteraction("count_users", _count_users)
         return ret
 
     @defer.inlineCallbacks
@@ -479,12 +481,12 @@ class RegistrationWorkerStore(SQLBaseStore):
 
         def _count_users(txn):
             txn.execute("SELECT COUNT(*) AS users FROM users where user_type is null")
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             if rows:
                 return rows[0]["users"]
             return 0
 
-        ret = yield self.db.runInteraction("count_real_users", _count_users)
+        ret = yield self.db_pool.runInteraction("count_real_users", _count_users)
         return ret
 
     async def generate_user_id(self) -> str:
@@ -492,7 +494,7 @@ class RegistrationWorkerStore(SQLBaseStore):
 
         Returns: a (hopefully) free localpart
         """
-        next_id = await self.db.runInteraction(
+        next_id = await self.db_pool.runInteraction(
             "generate_user_id", self._user_id_seq.get_next_id_txn
         )
 
@@ -508,7 +510,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             The user ID or None if no user id/threepid mapping exists
         """
-        user_id = await self.db.runInteraction(
+        user_id = await self.db_pool.runInteraction(
             "get_user_id_by_threepid", self.get_user_id_by_threepid_txn, medium, address
         )
         return user_id
@@ -524,7 +526,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             str|None: user id or None if no user id/threepid mapping exists
         """
-        ret = self.db.simple_select_one_txn(
+        ret = self.db_pool.simple_select_one_txn(
             txn,
             "user_threepids",
             {"medium": medium, "address": address},
@@ -537,7 +539,7 @@ class RegistrationWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def user_add_threepid(self, user_id, medium, address, validated_at, added_at):
-        yield self.db.simple_upsert(
+        yield self.db_pool.simple_upsert(
             "user_threepids",
             {"medium": medium, "address": address},
             {"user_id": user_id, "validated_at": validated_at, "added_at": added_at},
@@ -545,7 +547,7 @@ class RegistrationWorkerStore(SQLBaseStore):
 
     @defer.inlineCallbacks
     def user_get_threepids(self, user_id):
-        ret = yield self.db.simple_select_list(
+        ret = yield self.db_pool.simple_select_list(
             "user_threepids",
             {"user_id": user_id},
             ["medium", "address", "validated_at", "added_at"],
@@ -554,7 +556,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         return ret
 
     def user_delete_threepid(self, user_id, medium, address):
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             "user_threepids",
             keyvalues={"user_id": user_id, "medium": medium, "address": address},
             desc="user_delete_threepid",
@@ -567,7 +569,7 @@ class RegistrationWorkerStore(SQLBaseStore):
              user_id: The user id to delete all threepids of
 
         """
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             "user_threepids",
             keyvalues={"user_id": user_id},
             desc="user_delete_threepids",
@@ -589,7 +591,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         """
         # We need to use an upsert, in case they user had already bound the
         # threepid
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="user_threepid_id_server",
             keyvalues={
                 "user_id": user_id,
@@ -615,7 +617,7 @@ class RegistrationWorkerStore(SQLBaseStore):
                 medium (str): The medium of the threepid (e.g "email")
                 address (str): The address of the threepid (e.g "bob@example.com")
         """
-        return self.db.simple_select_list(
+        return self.db_pool.simple_select_list(
             table="user_threepid_id_server",
             keyvalues={"user_id": user_id},
             retcols=["medium", "address"],
@@ -636,7 +638,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             Deferred
         """
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             table="user_threepid_id_server",
             keyvalues={
                 "user_id": user_id,
@@ -659,7 +661,7 @@ class RegistrationWorkerStore(SQLBaseStore):
         Returns:
             Deferred[list[str]]: Resolves to a list of identity servers
         """
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="user_threepid_id_server",
             keyvalues={"user_id": user_id, "medium": medium, "address": address},
             retcol="id_server",
@@ -677,7 +679,7 @@ class RegistrationWorkerStore(SQLBaseStore):
             defer.Deferred(bool): The requested value.
         """
 
-        res = yield self.db.simple_select_one_onecol(
+        res = yield self.db_pool.simple_select_one_onecol(
             table="users",
             keyvalues={"name": user_id},
             retcol="deactivated",
@@ -744,13 +746,13 @@ class RegistrationWorkerStore(SQLBaseStore):
             sql += " LIMIT 1"
 
             txn.execute(sql, list(keyvalues.values()))
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             if not rows:
                 return None
 
             return rows[0]
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_threepid_validation_session", get_threepid_validation_session_txn
         )
 
@@ -764,37 +766,37 @@ class RegistrationWorkerStore(SQLBaseStore):
         """
 
         def delete_threepid_session_txn(txn):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="threepid_validation_token",
                 keyvalues={"session_id": session_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="threepid_validation_session",
                 keyvalues={"session_id": session_id},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "delete_threepid_session", delete_threepid_session_txn
         )
 
 
 class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RegistrationBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
         self.clock = hs.get_clock()
         self.config = hs.config
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "access_tokens_device_index",
             index_name="access_tokens_device_id",
             table="access_tokens",
             columns=["user_id", "device_id"],
         )
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "users_creation_ts",
             index_name="users_creation_ts",
             table="users",
@@ -804,13 +806,15 @@ class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
         # we no longer use refresh tokens, but it's possible that some people
         # might have a background update queued to build this index. Just
         # clear the background update.
-        self.db.updates.register_noop_background_update("refresh_tokens_device_index")
+        self.db_pool.updates.register_noop_background_update(
+            "refresh_tokens_device_index"
+        )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "user_threepids_grandfather", self._bg_user_threepids_grandfather
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "users_set_deactivated_flag", self._background_update_set_deactivated_flag
         )
 
@@ -843,7 +847,7 @@ class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
                 (last_user, batch_size),
             )
 
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
 
             if not rows:
                 return True, 0
@@ -857,7 +861,7 @@ class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
 
             logger.info("Marked %d rows as deactivated", rows_processed_nb)
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, "users_set_deactivated_flag", {"user_id": rows[-1]["name"]}
             )
 
@@ -866,12 +870,14 @@ class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
             else:
                 return False, len(rows)
 
-        end, nb_processed = yield self.db.runInteraction(
+        end, nb_processed = yield self.db_pool.runInteraction(
             "users_set_deactivated_flag", _background_update_set_deactivated_flag_txn
         )
 
         if end:
-            yield self.db.updates._end_background_update("users_set_deactivated_flag")
+            yield self.db_pool.updates._end_background_update(
+                "users_set_deactivated_flag"
+            )
 
         return nb_processed
 
@@ -897,17 +903,17 @@ class RegistrationBackgroundUpdateStore(RegistrationWorkerStore):
             txn.executemany(sql, [(id_server,) for id_server in id_servers])
 
         if id_servers:
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "_bg_user_threepids_grandfather", _bg_user_threepids_grandfather_txn
             )
 
-        yield self.db.updates._end_background_update("user_threepids_grandfather")
+        yield self.db_pool.updates._end_background_update("user_threepids_grandfather")
 
         return 1
 
 
 class RegistrationStore(RegistrationBackgroundUpdateStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RegistrationStore, self).__init__(database, db_conn, hs)
 
         self._account_validity = hs.config.account_validity
@@ -947,7 +953,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         """
         next_id = self._access_tokens_id_gen.get_next()
 
-        yield self.db.simple_insert(
+        yield self.db_pool.simple_insert(
             "access_tokens",
             {
                 "id": next_id,
@@ -992,7 +998,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         Returns:
             Deferred
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "register_user",
             self._register_user,
             user_id,
@@ -1026,7 +1032,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                 # Ensure that the guest user actually exists
                 # ``allow_none=False`` makes this raise an exception
                 # if the row isn't in the database.
-                self.db.simple_select_one_txn(
+                self.db_pool.simple_select_one_txn(
                     txn,
                     "users",
                     keyvalues={"name": user_id, "is_guest": 1},
@@ -1034,7 +1040,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                     allow_none=False,
                 )
 
-                self.db.simple_update_one_txn(
+                self.db_pool.simple_update_one_txn(
                     txn,
                     "users",
                     keyvalues={"name": user_id, "is_guest": 1},
@@ -1048,7 +1054,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                     },
                 )
             else:
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     "users",
                     values={
@@ -1103,7 +1109,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             external_id: id on that system
             user_id: complete mxid that it is mapped to
         """
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="user_external_ids",
             values={
                 "auth_provider": auth_provider,
@@ -1121,12 +1127,12 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         """
 
         def user_set_password_hash_txn(txn):
-            self.db.simple_update_one_txn(
+            self.db_pool.simple_update_one_txn(
                 txn, "users", {"name": user_id}, {"password_hash": password_hash}
             )
             self._invalidate_cache_and_stream(txn, self.get_user_by_id, (user_id,))
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "user_set_password_hash", user_set_password_hash_txn
         )
 
@@ -1143,7 +1149,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         """
 
         def f(txn):
-            self.db.simple_update_one_txn(
+            self.db_pool.simple_update_one_txn(
                 txn,
                 table="users",
                 keyvalues={"name": user_id},
@@ -1151,7 +1157,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             )
             self._invalidate_cache_and_stream(txn, self.get_user_by_id, (user_id,))
 
-        return self.db.runInteraction("user_set_consent_version", f)
+        return self.db_pool.runInteraction("user_set_consent_version", f)
 
     def user_set_consent_server_notice_sent(self, user_id, consent_version):
         """Updates the user table to record that we have sent the user a server
@@ -1167,7 +1173,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         """
 
         def f(txn):
-            self.db.simple_update_one_txn(
+            self.db_pool.simple_update_one_txn(
                 txn,
                 table="users",
                 keyvalues={"name": user_id},
@@ -1175,7 +1181,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             )
             self._invalidate_cache_and_stream(txn, self.get_user_by_id, (user_id,))
 
-        return self.db.runInteraction("user_set_consent_server_notice_sent", f)
+        return self.db_pool.runInteraction("user_set_consent_server_notice_sent", f)
 
     def user_delete_access_tokens(self, user_id, except_token_id=None, device_id=None):
         """
@@ -1221,11 +1227,11 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
 
             return tokens_and_devices
 
-        return self.db.runInteraction("user_delete_access_tokens", f)
+        return self.db_pool.runInteraction("user_delete_access_tokens", f)
 
     def delete_access_token(self, access_token):
         def f(txn):
-            self.db.simple_delete_one_txn(
+            self.db_pool.simple_delete_one_txn(
                 txn, table="access_tokens", keyvalues={"token": access_token}
             )
 
@@ -1233,11 +1239,11 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                 txn, self.get_user_by_access_token, (access_token,)
             )
 
-        return self.db.runInteraction("delete_access_token", f)
+        return self.db_pool.runInteraction("delete_access_token", f)
 
     @cachedInlineCallbacks()
     def is_guest(self, user_id):
-        res = yield self.db.simple_select_one_onecol(
+        res = yield self.db_pool.simple_select_one_onecol(
             table="users",
             keyvalues={"name": user_id},
             retcol="is_guest",
@@ -1252,7 +1258,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         Adds a user to the table of users who need to be parted from all the rooms they're
         in
         """
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             "users_pending_deactivation",
             values={"user_id": user_id},
             desc="add_user_pending_deactivation",
@@ -1265,7 +1271,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         """
         # XXX: This should be simple_delete_one but we failed to put a unique index on
         # the table, so somehow duplicate entries have ended up in it.
-        return self.db.simple_delete(
+        return self.db_pool.simple_delete(
             "users_pending_deactivation",
             keyvalues={"user_id": user_id},
             desc="del_user_pending_deactivation",
@@ -1276,7 +1282,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         Gets one user from the table of users waiting to be parted from all the rooms
         they're in.
         """
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             "users_pending_deactivation",
             keyvalues={},
             retcol="user_id",
@@ -1306,7 +1312,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
 
         # Insert everything into a transaction in order to run atomically
         def validate_threepid_session_txn(txn):
-            row = self.db.simple_select_one_txn(
+            row = self.db_pool.simple_select_one_txn(
                 txn,
                 table="threepid_validation_session",
                 keyvalues={"session_id": session_id},
@@ -1324,7 +1330,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                     400, "This client_secret does not match the provided session_id"
                 )
 
-            row = self.db.simple_select_one_txn(
+            row = self.db_pool.simple_select_one_txn(
                 txn,
                 table="threepid_validation_token",
                 keyvalues={"session_id": session_id, "token": token},
@@ -1349,7 +1355,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                 )
 
             # Looks good. Validate the session
-            self.db.simple_update_txn(
+            self.db_pool.simple_update_txn(
                 txn,
                 table="threepid_validation_session",
                 keyvalues={"session_id": session_id},
@@ -1359,7 +1365,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             return next_link
 
         # Return next_link if it exists
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "validate_threepid_session_txn", validate_threepid_session_txn
         )
 
@@ -1392,7 +1398,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         if validated_at:
             insertion_values["validated_at"] = validated_at
 
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="threepid_validation_session",
             keyvalues={"session_id": session_id},
             values={"last_send_attempt": send_attempt},
@@ -1430,7 +1436,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
 
         def start_or_continue_validation_session_txn(txn):
             # Create or update a validation session
-            self.db.simple_upsert_txn(
+            self.db_pool.simple_upsert_txn(
                 txn,
                 table="threepid_validation_session",
                 keyvalues={"session_id": session_id},
@@ -1443,7 +1449,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             )
 
             # Create a new validation token with this session ID
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="threepid_validation_token",
                 values={
@@ -1454,7 +1460,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                 },
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "start_or_continue_validation_session",
             start_or_continue_validation_session_txn,
         )
@@ -1469,7 +1475,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             """
             return txn.execute(sql, (ts,))
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "cull_expired_threepid_validation_tokens",
             cull_expired_threepid_validation_tokens_txn,
             self.clock.time_msec(),
@@ -1484,7 +1490,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             deactivated (bool): The value to set for `deactivated`.
         """
 
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "set_user_deactivated_status",
             self.set_user_deactivated_status_txn,
             user_id,
@@ -1492,7 +1498,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
         )
 
     def set_user_deactivated_status_txn(self, txn, user_id, deactivated):
-        self.db.simple_update_one_txn(
+        self.db_pool.simple_update_one_txn(
             txn=txn,
             table="users",
             keyvalues={"name": user_id},
@@ -1520,14 +1526,14 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
             )
             txn.execute(sql, [])
 
-            res = self.db.cursor_to_dict(txn)
+            res = self.db_pool.cursor_to_dict(txn)
             if res:
                 for user in res:
                     self.set_expiration_date_for_user_txn(
                         txn, user["name"], use_delta=True
                     )
 
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "get_users_with_no_expiration_date",
             select_users_with_no_expiration_date_txn,
         )
@@ -1551,7 +1557,7 @@ class RegistrationStore(RegistrationBackgroundUpdateStore):
                 expiration_ts,
             )
 
-        self.db.simple_upsert_txn(
+        self.db_pool.simple_upsert_txn(
             txn,
             "account_validity",
             keyvalues={"user_id": user_id},
diff --git a/synapse/storage/data_stores/main/rejections.py b/synapse/storage/databases/main/rejections.py
index 27e5a2084a..cf9ba51205 100644
--- a/synapse/storage/data_stores/main/rejections.py
+++ b/synapse/storage/databases/main/rejections.py
@@ -22,7 +22,7 @@ logger = logging.getLogger(__name__)
 
 class RejectionsStore(SQLBaseStore):
     def get_rejection_reason(self, event_id):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="rejections",
             retcol="reason",
             keyvalues={"event_id": event_id},
diff --git a/synapse/storage/data_stores/main/relations.py b/synapse/storage/databases/main/relations.py
index 7d477f8d01..b81f1449b7 100644
--- a/synapse/storage/data_stores/main/relations.py
+++ b/synapse/storage/databases/main/relations.py
@@ -19,7 +19,7 @@ import attr
 
 from synapse.api.constants import RelationTypes
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.stream import generate_pagination_where_clause
+from synapse.storage.databases.main.stream import generate_pagination_where_clause
 from synapse.storage.relations import (
     AggregationPaginationToken,
     PaginationChunk,
@@ -129,7 +129,7 @@ class RelationsWorkerStore(SQLBaseStore):
                 chunk=list(events[:limit]), next_batch=next_batch, prev_batch=from_token
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_recent_references_for_event", _get_recent_references_for_event_txn
         )
 
@@ -223,7 +223,7 @@ class RelationsWorkerStore(SQLBaseStore):
                 chunk=list(events[:limit]), next_batch=next_batch, prev_batch=from_token
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_aggregation_groups_for_event", _get_aggregation_groups_for_event_txn
         )
 
@@ -268,7 +268,7 @@ class RelationsWorkerStore(SQLBaseStore):
             if row:
                 return row[0]
 
-        edit_id = yield self.db.runInteraction(
+        edit_id = yield self.db_pool.runInteraction(
             "get_applicable_edit", _get_applicable_edit_txn
         )
 
@@ -318,7 +318,7 @@ class RelationsWorkerStore(SQLBaseStore):
 
             return bool(txn.fetchone())
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_if_user_has_annotated_event", _get_if_user_has_annotated_event
         )
 
diff --git a/synapse/storage/data_stores/main/room.py b/synapse/storage/databases/main/room.py
index ab48052cdc..f4008e6221 100644
--- a/synapse/storage/data_stores/main/room.py
+++ b/synapse/storage/databases/main/room.py
@@ -27,8 +27,8 @@ from synapse.api.constants import EventTypes
 from synapse.api.errors import StoreError
 from synapse.api.room_versions import RoomVersion, RoomVersions
 from synapse.storage._base import SQLBaseStore, db_to_json
-from synapse.storage.data_stores.main.search import SearchStore
-from synapse.storage.database import Database, LoggingTransaction
+from synapse.storage.database import DatabasePool, LoggingTransaction
+from synapse.storage.databases.main.search import SearchStore
 from synapse.types import ThirdPartyInstanceID
 from synapse.util.caches.descriptors import cached
 
@@ -73,7 +73,7 @@ class RoomSortOrder(Enum):
 
 
 class RoomWorkerStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RoomWorkerStore, self).__init__(database, db_conn, hs)
 
         self.config = hs.config
@@ -86,7 +86,7 @@ class RoomWorkerStore(SQLBaseStore):
         Returns:
             A dict containing the room information, or None if the room is unknown.
         """
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             table="rooms",
             keyvalues={"room_id": room_id},
             retcols=("room_id", "is_public", "creator"),
@@ -118,7 +118,7 @@ class RoomWorkerStore(SQLBaseStore):
             txn.execute(sql, [room_id])
             # Catch error if sql returns empty result to return "None" instead of an error
             try:
-                res = self.db.cursor_to_dict(txn)[0]
+                res = self.db_pool.cursor_to_dict(txn)[0]
             except IndexError:
                 return None
 
@@ -126,12 +126,12 @@ class RoomWorkerStore(SQLBaseStore):
             res["public"] = bool(res["public"])
             return res
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_room_with_stats", get_room_with_stats_txn, room_id
         )
 
     def get_public_room_ids(self):
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="rooms",
             keyvalues={"is_public": True},
             retcol="room_id",
@@ -188,7 +188,9 @@ class RoomWorkerStore(SQLBaseStore):
             txn.execute(sql, query_args)
             return txn.fetchone()[0]
 
-        return self.db.runInteraction("count_public_rooms", _count_public_rooms_txn)
+        return self.db_pool.runInteraction(
+            "count_public_rooms", _count_public_rooms_txn
+        )
 
     async def get_largest_public_rooms(
         self,
@@ -320,21 +322,21 @@ class RoomWorkerStore(SQLBaseStore):
         def _get_largest_public_rooms_txn(txn):
             txn.execute(sql, query_args)
 
-            results = self.db.cursor_to_dict(txn)
+            results = self.db_pool.cursor_to_dict(txn)
 
             if not forwards:
                 results.reverse()
 
             return results
 
-        ret_val = await self.db.runInteraction(
+        ret_val = await self.db_pool.runInteraction(
             "get_largest_public_rooms", _get_largest_public_rooms_txn
         )
         return ret_val
 
     @cached(max_entries=10000)
     def is_room_blocked(self, room_id):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="blocked_rooms",
             keyvalues={"room_id": room_id},
             retcol="1",
@@ -502,7 +504,7 @@ class RoomWorkerStore(SQLBaseStore):
             room_count = txn.fetchone()
             return rooms, room_count[0]
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_rooms_paginate", _get_rooms_paginate_txn,
         )
 
@@ -519,7 +521,7 @@ class RoomWorkerStore(SQLBaseStore):
             of RatelimitOverride are None or 0 then ratelimitng has been
             disabled for that user entirely.
         """
-        row = await self.db.simple_select_one(
+        row = await self.db_pool.simple_select_one(
             table="ratelimit_override",
             keyvalues={"user_id": user_id},
             retcols=("messages_per_second", "burst_count"),
@@ -561,9 +563,9 @@ class RoomWorkerStore(SQLBaseStore):
                 (room_id,),
             )
 
-            return self.db.cursor_to_dict(txn)
+            return self.db_pool.cursor_to_dict(txn)
 
-        ret = await self.db.runInteraction(
+        ret = await self.db_pool.runInteraction(
             "get_retention_policy_for_room", get_retention_policy_for_room_txn,
         )
 
@@ -613,7 +615,7 @@ class RoomWorkerStore(SQLBaseStore):
 
             return local_media_mxcs, remote_media_mxcs
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_media_ids_in_room", _get_media_mxcs_in_room_txn
         )
 
@@ -630,7 +632,7 @@ class RoomWorkerStore(SQLBaseStore):
                 txn, local_mxcs, remote_mxcs, quarantined_by
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "quarantine_media_in_room", _quarantine_media_in_room_txn
         )
 
@@ -714,7 +716,7 @@ class RoomWorkerStore(SQLBaseStore):
                 txn, local_mxcs, remote_mxcs, quarantined_by
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "quarantine_media_by_user", _quarantine_media_by_id_txn
         )
 
@@ -730,7 +732,7 @@ class RoomWorkerStore(SQLBaseStore):
             local_media_ids = self._get_media_ids_by_user_txn(txn, user_id)
             return self._quarantine_media_txn(txn, local_media_ids, [], quarantined_by)
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "quarantine_media_by_user", _quarantine_media_by_user_txn
         )
 
@@ -848,7 +850,7 @@ class RoomWorkerStore(SQLBaseStore):
 
             return updates, upto_token, limited
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_all_new_public_rooms", get_all_new_public_rooms
         )
 
@@ -857,21 +859,21 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
     REMOVE_TOMESTONED_ROOMS_BG_UPDATE = "remove_tombstoned_rooms_from_directory"
     ADD_ROOMS_ROOM_VERSION_COLUMN = "add_rooms_room_version_column"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RoomBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
         self.config = hs.config
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "insert_room_retention", self._background_insert_retention,
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.REMOVE_TOMESTONED_ROOMS_BG_UPDATE,
             self._remove_tombstoned_rooms_from_directory,
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.ADD_ROOMS_ROOM_VERSION_COLUMN,
             self._background_add_rooms_room_version_column,
         )
@@ -900,7 +902,7 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
                 (last_room, batch_size),
             )
 
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
 
             if not rows:
                 return True
@@ -912,7 +914,7 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
                     ev = db_to_json(row["json"])
                     retention_policy = ev["content"]
 
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn=txn,
                     table="room_retention",
                     values={
@@ -925,7 +927,7 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
 
             logger.info("Inserted %d rows into room_retention", len(rows))
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, "insert_room_retention", {"room_id": rows[-1]["room_id"]}
             )
 
@@ -934,12 +936,12 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
             else:
                 return False
 
-        end = await self.db.runInteraction(
+        end = await self.db_pool.runInteraction(
             "insert_room_retention", _background_insert_retention_txn,
         )
 
         if end:
-            await self.db.updates._end_background_update("insert_room_retention")
+            await self.db_pool.updates._end_background_update("insert_room_retention")
 
         return batch_size
 
@@ -983,7 +985,7 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
                 # mainly for paranoia as much badness would happen if we don't
                 # insert the row and then try and get the room version for the
                 # room.
-                self.db.simple_upsert_txn(
+                self.db_pool.simple_upsert_txn(
                     txn,
                     table="rooms",
                     keyvalues={"room_id": room_id},
@@ -992,19 +994,19 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
                 )
                 new_last_room_id = room_id
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, self.ADD_ROOMS_ROOM_VERSION_COLUMN, {"room_id": new_last_room_id}
             )
 
             return False
 
-        end = await self.db.runInteraction(
+        end = await self.db_pool.runInteraction(
             "_background_add_rooms_room_version_column",
             _background_add_rooms_room_version_column_txn,
         )
 
         if end:
-            await self.db.updates._end_background_update(
+            await self.db_pool.updates._end_background_update(
                 self.ADD_ROOMS_ROOM_VERSION_COLUMN
             )
 
@@ -1038,12 +1040,12 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
 
             return [row[0] for row in txn]
 
-        rooms = await self.db.runInteraction(
+        rooms = await self.db_pool.runInteraction(
             "get_tombstoned_directory_rooms", _get_rooms
         )
 
         if not rooms:
-            await self.db.updates._end_background_update(
+            await self.db_pool.updates._end_background_update(
                 self.REMOVE_TOMESTONED_ROOMS_BG_UPDATE
             )
             return 0
@@ -1052,7 +1054,7 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
             logger.info("Removing tombstoned room %s from the directory", room_id)
             await self.set_room_is_public(room_id, False)
 
-        await self.db.updates._background_update_progress(
+        await self.db_pool.updates._background_update_progress(
             self.REMOVE_TOMESTONED_ROOMS_BG_UPDATE, {"room_id": rooms[-1]}
         )
 
@@ -1068,7 +1070,7 @@ class RoomBackgroundUpdateStore(SQLBaseStore):
 
 
 class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RoomStore, self).__init__(database, db_conn, hs)
 
         self.config = hs.config
@@ -1079,7 +1081,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
         Called when we join a room over federation, and overwrites any room version
         currently in the table.
         """
-        await self.db.simple_upsert(
+        await self.db_pool.simple_upsert(
             desc="upsert_room_on_join",
             table="rooms",
             keyvalues={"room_id": room_id},
@@ -1111,7 +1113,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
         try:
 
             def store_room_txn(txn, next_id):
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     "rooms",
                     {
@@ -1122,7 +1124,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                     },
                 )
                 if is_public:
-                    self.db.simple_insert_txn(
+                    self.db_pool.simple_insert_txn(
                         txn,
                         table="public_room_list_stream",
                         values={
@@ -1133,7 +1135,9 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                     )
 
             with self._public_room_id_gen.get_next() as next_id:
-                await self.db.runInteraction("store_room_txn", store_room_txn, next_id)
+                await self.db_pool.runInteraction(
+                    "store_room_txn", store_room_txn, next_id
+                )
         except Exception as e:
             logger.error("store_room with room_id=%s failed: %s", room_id, e)
             raise StoreError(500, "Problem creating room.")
@@ -1143,7 +1147,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
         When we receive an invite over federation, store the version of the room if we
         don't already know the room version.
         """
-        await self.db.simple_upsert(
+        await self.db_pool.simple_upsert(
             desc="maybe_store_room_on_invite",
             table="rooms",
             keyvalues={"room_id": room_id},
@@ -1160,14 +1164,14 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
 
     async def set_room_is_public(self, room_id, is_public):
         def set_room_is_public_txn(txn, next_id):
-            self.db.simple_update_one_txn(
+            self.db_pool.simple_update_one_txn(
                 txn,
                 table="rooms",
                 keyvalues={"room_id": room_id},
                 updatevalues={"is_public": is_public},
             )
 
-            entries = self.db.simple_select_list_txn(
+            entries = self.db_pool.simple_select_list_txn(
                 txn,
                 table="public_room_list_stream",
                 keyvalues={
@@ -1185,7 +1189,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                 add_to_stream = bool(entries[-1]["visibility"]) != is_public
 
             if add_to_stream:
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     table="public_room_list_stream",
                     values={
@@ -1198,7 +1202,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                 )
 
         with self._public_room_id_gen.get_next() as next_id:
-            await self.db.runInteraction(
+            await self.db_pool.runInteraction(
                 "set_room_is_public", set_room_is_public_txn, next_id
             )
         self.hs.get_notifier().on_new_replication_data()
@@ -1224,7 +1228,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
         def set_room_is_public_appservice_txn(txn, next_id):
             if is_public:
                 try:
-                    self.db.simple_insert_txn(
+                    self.db_pool.simple_insert_txn(
                         txn,
                         table="appservice_room_list",
                         values={
@@ -1237,7 +1241,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                     # We've already inserted, nothing to do.
                     return
             else:
-                self.db.simple_delete_txn(
+                self.db_pool.simple_delete_txn(
                     txn,
                     table="appservice_room_list",
                     keyvalues={
@@ -1247,7 +1251,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                     },
                 )
 
-            entries = self.db.simple_select_list_txn(
+            entries = self.db_pool.simple_select_list_txn(
                 txn,
                 table="public_room_list_stream",
                 keyvalues={
@@ -1265,7 +1269,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                 add_to_stream = bool(entries[-1]["visibility"]) != is_public
 
             if add_to_stream:
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     table="public_room_list_stream",
                     values={
@@ -1278,7 +1282,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
                 )
 
         with self._public_room_id_gen.get_next() as next_id:
-            await self.db.runInteraction(
+            await self.db_pool.runInteraction(
                 "set_room_is_public_appservice",
                 set_room_is_public_appservice_txn,
                 next_id,
@@ -1295,13 +1299,13 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
             row = txn.fetchone()
             return row[0] or 0
 
-        return self.db.runInteraction("get_rooms", f)
+        return self.db_pool.runInteraction("get_rooms", f)
 
     def add_event_report(
         self, room_id, event_id, user_id, reason, content, received_ts
     ):
         next_id = self._event_reports_id_gen.get_next()
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="event_reports",
             values={
                 "id": next_id,
@@ -1325,14 +1329,14 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
             room_id: Room to block
             user_id: Who blocked it
         """
-        await self.db.simple_upsert(
+        await self.db_pool.simple_upsert(
             table="blocked_rooms",
             keyvalues={"room_id": room_id},
             values={},
             insertion_values={"user_id": user_id},
             desc="block_room",
         )
-        await self.db.runInteraction(
+        await self.db_pool.runInteraction(
             "block_room_invalidation",
             self._invalidate_cache_and_stream,
             self.is_room_blocked,
@@ -1388,7 +1392,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
 
             txn.execute(sql, args)
 
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             rooms_dict = {}
 
             for row in rows:
@@ -1404,7 +1408,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
 
                 txn.execute(sql)
 
-                rows = self.db.cursor_to_dict(txn)
+                rows = self.db_pool.cursor_to_dict(txn)
 
                 # If a room isn't already in the dict (i.e. it doesn't have a retention
                 # policy in its state), add it with a null policy.
@@ -1417,7 +1421,7 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
 
             return rooms_dict
 
-        rooms = await self.db.runInteraction(
+        rooms = await self.db_pool.runInteraction(
             "get_rooms_for_retention_period_in_range",
             get_rooms_for_retention_period_in_range_txn,
         )
diff --git a/synapse/storage/data_stores/main/roommember.py b/synapse/storage/databases/main/roommember.py
index a92e401e88..7c5be251bd 100644
--- a/synapse/storage/data_stores/main/roommember.py
+++ b/synapse/storage/databases/main/roommember.py
@@ -28,8 +28,8 @@ from synapse.storage._base import (
     db_to_json,
     make_in_list_sql_clause,
 )
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
 from synapse.storage.engines import Sqlite3Engine
 from synapse.storage.roommember import (
     GetRoomsForUserWithStreamOrdering,
@@ -51,7 +51,7 @@ _CURRENT_STATE_MEMBERSHIP_UPDATE_NAME = "current_state_events_membership"
 
 
 class RoomMemberWorkerStore(EventsWorkerStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RoomMemberWorkerStore, self).__init__(database, db_conn, hs)
 
         # Is the current_state_events.membership up to date? Or is the
@@ -116,7 +116,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             txn.execute(query)
             return list(txn)[0][0]
 
-        count = yield self.db.runInteraction("get_known_servers", _transact)
+        count = yield self.db_pool.runInteraction("get_known_servers", _transact)
 
         # We always know about ourselves, even if we have nothing in
         # room_memberships (for example, the server is new).
@@ -128,7 +128,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         membership column is up to date
         """
 
-        pending_update = self.db.simple_select_one_txn(
+        pending_update = self.db_pool.simple_select_one_txn(
             txn,
             table="background_updates",
             keyvalues={"update_name": _CURRENT_STATE_MEMBERSHIP_UPDATE_NAME},
@@ -144,14 +144,14 @@ class RoomMemberWorkerStore(EventsWorkerStore):
                 15.0,
                 run_as_background_process,
                 "_check_safe_current_state_events_membership_updated",
-                self.db.runInteraction,
+                self.db_pool.runInteraction,
                 "_check_safe_current_state_events_membership_updated",
                 self._check_safe_current_state_events_membership_updated_txn,
             )
 
     @cached(max_entries=100000, iterable=True)
     def get_users_in_room(self, room_id):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_users_in_room", self.get_users_in_room_txn, room_id
         )
 
@@ -259,7 +259,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
 
             return res
 
-        return self.db.runInteraction("get_room_summary", _get_room_summary_txn)
+        return self.db_pool.runInteraction("get_room_summary", _get_room_summary_txn)
 
     def _get_user_counts_in_room_txn(self, txn, room_id):
         """
@@ -332,7 +332,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         if not membership_list:
             return defer.succeed(None)
 
-        rooms = yield self.db.runInteraction(
+        rooms = yield self.db_pool.runInteraction(
             "get_rooms_for_local_user_where_membership_is",
             self._get_rooms_for_local_user_where_membership_is_txn,
             user_id,
@@ -369,7 +369,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         )
 
         txn.execute(sql, (user_id, *args))
-        results = [RoomsForUser(**r) for r in self.db.cursor_to_dict(txn)]
+        results = [RoomsForUser(**r) for r in self.db_pool.cursor_to_dict(txn)]
 
         return results
 
@@ -388,7 +388,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             the rooms the user is in currently, along with the stream ordering
             of the most recent join for that user and room.
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_rooms_for_user_with_stream_ordering",
             self._get_rooms_for_user_with_stream_ordering_txn,
             user_id,
@@ -453,7 +453,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
 
             return {row[0] for row in txn}
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "get_users_server_still_shares_room_with",
             _get_users_server_still_shares_room_with_txn,
         )
@@ -624,7 +624,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             to `user_id` and ProfileInfo (or None if not join event).
         """
 
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="room_memberships",
             column="event_id",
             iterable=event_ids,
@@ -664,7 +664,9 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         # the returned user actually has the correct domain.
         like_clause = "%:" + host
 
-        rows = yield self.db.execute("is_host_joined", None, sql, room_id, like_clause)
+        rows = yield self.db_pool.execute(
+            "is_host_joined", None, sql, room_id, like_clause
+        )
 
         if not rows:
             return False
@@ -704,7 +706,9 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         # the returned user actually has the correct domain.
         like_clause = "%:" + host
 
-        rows = yield self.db.execute("was_host_joined", None, sql, room_id, like_clause)
+        rows = yield self.db_pool.execute(
+            "was_host_joined", None, sql, room_id, like_clause
+        )
 
         if not rows:
             return False
@@ -774,7 +778,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             rows = txn.fetchall()
             return rows[0][0]
 
-        count = yield self.db.runInteraction("did_forget_membership", f)
+        count = yield self.db_pool.runInteraction("did_forget_membership", f)
         return count == 0
 
     @cached()
@@ -811,7 +815,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             txn.execute(sql, (user_id,))
             return {row[0] for row in txn if row[1] == 0}
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_forgotten_rooms_for_user", _get_forgotten_rooms_for_user_txn
         )
 
@@ -826,7 +830,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             Deferred[set[str]]: Set of room IDs.
         """
 
-        room_ids = yield self.db.simple_select_onecol(
+        room_ids = yield self.db_pool.simple_select_onecol(
             table="room_memberships",
             keyvalues={"membership": Membership.JOIN, "user_id": user_id},
             retcol="room_id",
@@ -841,7 +845,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         """Get user_id and membership of a set of event IDs.
         """
 
-        return self.db.simple_select_many_batch(
+        return self.db_pool.simple_select_many_batch(
             table="room_memberships",
             column="event_id",
             iterable=member_event_ids,
@@ -877,23 +881,23 @@ class RoomMemberWorkerStore(EventsWorkerStore):
 
             return bool(txn.fetchone())
 
-        return await self.db.runInteraction(
+        return await self.db_pool.runInteraction(
             "is_local_host_in_room_ignoring_users",
             _is_local_host_in_room_ignoring_users_txn,
         )
 
 
 class RoomMemberBackgroundUpdateStore(SQLBaseStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RoomMemberBackgroundUpdateStore, self).__init__(database, db_conn, hs)
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             _MEMBERSHIP_PROFILE_UPDATE_NAME, self._background_add_membership_profile
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             _CURRENT_STATE_MEMBERSHIP_UPDATE_NAME,
             self._background_current_state_membership,
         )
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             "room_membership_forgotten_idx",
             index_name="room_memberships_user_room_forgotten",
             table="room_memberships",
@@ -926,7 +930,7 @@ class RoomMemberBackgroundUpdateStore(SQLBaseStore):
 
             txn.execute(sql, (target_min_stream_id, max_stream_id, batch_size))
 
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             if not rows:
                 return 0
 
@@ -961,18 +965,18 @@ class RoomMemberBackgroundUpdateStore(SQLBaseStore):
                 "max_stream_id_exclusive": min_stream_id,
             }
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, _MEMBERSHIP_PROFILE_UPDATE_NAME, progress
             )
 
             return len(rows)
 
-        result = yield self.db.runInteraction(
+        result = yield self.db_pool.runInteraction(
             _MEMBERSHIP_PROFILE_UPDATE_NAME, add_membership_profile_txn
         )
 
         if not result:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 _MEMBERSHIP_PROFILE_UPDATE_NAME
             )
 
@@ -1013,7 +1017,7 @@ class RoomMemberBackgroundUpdateStore(SQLBaseStore):
 
                 last_processed_room = next_room
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn,
                 _CURRENT_STATE_MEMBERSHIP_UPDATE_NAME,
                 {"last_processed_room": last_processed_room},
@@ -1025,14 +1029,14 @@ class RoomMemberBackgroundUpdateStore(SQLBaseStore):
         # string, which will compare before all room IDs correctly.
         last_processed_room = progress.get("last_processed_room", "")
 
-        row_count, finished = yield self.db.runInteraction(
+        row_count, finished = yield self.db_pool.runInteraction(
             "_background_current_state_membership_update",
             _background_current_state_membership_txn,
             last_processed_room,
         )
 
         if finished:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 _CURRENT_STATE_MEMBERSHIP_UPDATE_NAME
             )
 
@@ -1040,7 +1044,7 @@ class RoomMemberBackgroundUpdateStore(SQLBaseStore):
 
 
 class RoomMemberStore(RoomMemberWorkerStore, RoomMemberBackgroundUpdateStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(RoomMemberStore, self).__init__(database, db_conn, hs)
 
     def forget(self, user_id, room_id):
@@ -1064,7 +1068,7 @@ class RoomMemberStore(RoomMemberWorkerStore, RoomMemberBackgroundUpdateStore):
                 txn, self.get_forgotten_rooms_for_user, (user_id,)
             )
 
-        return self.db.runInteraction("forget_membership", f)
+        return self.db_pool.runInteraction("forget_membership", f)
 
 
 class _JoinedHostsCache(object):
diff --git a/synapse/storage/data_stores/main/schema/delta/12/v12.sql b/synapse/storage/databases/main/schema/delta/12/v12.sql
index 5964c5aaac..5964c5aaac 100644
--- a/synapse/storage/data_stores/main/schema/delta/12/v12.sql
+++ b/synapse/storage/databases/main/schema/delta/12/v12.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/13/v13.sql b/synapse/storage/databases/main/schema/delta/13/v13.sql
index f8649e5d99..f8649e5d99 100644
--- a/synapse/storage/data_stores/main/schema/delta/13/v13.sql
+++ b/synapse/storage/databases/main/schema/delta/13/v13.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/14/v14.sql b/synapse/storage/databases/main/schema/delta/14/v14.sql
index a831920da6..a831920da6 100644
--- a/synapse/storage/data_stores/main/schema/delta/14/v14.sql
+++ b/synapse/storage/databases/main/schema/delta/14/v14.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/15/appservice_txns.sql b/synapse/storage/databases/main/schema/delta/15/appservice_txns.sql
index e4f5e76aec..e4f5e76aec 100644
--- a/synapse/storage/data_stores/main/schema/delta/15/appservice_txns.sql
+++ b/synapse/storage/databases/main/schema/delta/15/appservice_txns.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/15/presence_indices.sql b/synapse/storage/databases/main/schema/delta/15/presence_indices.sql
index 6b8d0f1ca7..6b8d0f1ca7 100644
--- a/synapse/storage/data_stores/main/schema/delta/15/presence_indices.sql
+++ b/synapse/storage/databases/main/schema/delta/15/presence_indices.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/15/v15.sql b/synapse/storage/databases/main/schema/delta/15/v15.sql
index 9523d2bcc3..9523d2bcc3 100644
--- a/synapse/storage/data_stores/main/schema/delta/15/v15.sql
+++ b/synapse/storage/databases/main/schema/delta/15/v15.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/16/events_order_index.sql b/synapse/storage/databases/main/schema/delta/16/events_order_index.sql
index a48f215170..a48f215170 100644
--- a/synapse/storage/data_stores/main/schema/delta/16/events_order_index.sql
+++ b/synapse/storage/databases/main/schema/delta/16/events_order_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/16/remote_media_cache_index.sql b/synapse/storage/databases/main/schema/delta/16/remote_media_cache_index.sql
index 7a15265cb1..7a15265cb1 100644
--- a/synapse/storage/data_stores/main/schema/delta/16/remote_media_cache_index.sql
+++ b/synapse/storage/databases/main/schema/delta/16/remote_media_cache_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/16/remove_duplicates.sql b/synapse/storage/databases/main/schema/delta/16/remove_duplicates.sql
index 65c97b5e2f..65c97b5e2f 100644
--- a/synapse/storage/data_stores/main/schema/delta/16/remove_duplicates.sql
+++ b/synapse/storage/databases/main/schema/delta/16/remove_duplicates.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/16/room_alias_index.sql b/synapse/storage/databases/main/schema/delta/16/room_alias_index.sql
index f82486132b..f82486132b 100644
--- a/synapse/storage/data_stores/main/schema/delta/16/room_alias_index.sql
+++ b/synapse/storage/databases/main/schema/delta/16/room_alias_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/16/unique_constraints.sql b/synapse/storage/databases/main/schema/delta/16/unique_constraints.sql
index 5b8de52c33..5b8de52c33 100644
--- a/synapse/storage/data_stores/main/schema/delta/16/unique_constraints.sql
+++ b/synapse/storage/databases/main/schema/delta/16/unique_constraints.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/16/users.sql b/synapse/storage/databases/main/schema/delta/16/users.sql
index cd0709250d..cd0709250d 100644
--- a/synapse/storage/data_stores/main/schema/delta/16/users.sql
+++ b/synapse/storage/databases/main/schema/delta/16/users.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/17/drop_indexes.sql b/synapse/storage/databases/main/schema/delta/17/drop_indexes.sql
index 7c9a90e27f..7c9a90e27f 100644
--- a/synapse/storage/data_stores/main/schema/delta/17/drop_indexes.sql
+++ b/synapse/storage/databases/main/schema/delta/17/drop_indexes.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/17/server_keys.sql b/synapse/storage/databases/main/schema/delta/17/server_keys.sql
index 70b247a06b..70b247a06b 100644
--- a/synapse/storage/data_stores/main/schema/delta/17/server_keys.sql
+++ b/synapse/storage/databases/main/schema/delta/17/server_keys.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/17/user_threepids.sql b/synapse/storage/databases/main/schema/delta/17/user_threepids.sql
index c17715ac80..c17715ac80 100644
--- a/synapse/storage/data_stores/main/schema/delta/17/user_threepids.sql
+++ b/synapse/storage/databases/main/schema/delta/17/user_threepids.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/18/server_keys_bigger_ints.sql b/synapse/storage/databases/main/schema/delta/18/server_keys_bigger_ints.sql
index 6e0871c92b..6e0871c92b 100644
--- a/synapse/storage/data_stores/main/schema/delta/18/server_keys_bigger_ints.sql
+++ b/synapse/storage/databases/main/schema/delta/18/server_keys_bigger_ints.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/19/event_index.sql b/synapse/storage/databases/main/schema/delta/19/event_index.sql
index 18b97b4332..18b97b4332 100644
--- a/synapse/storage/data_stores/main/schema/delta/19/event_index.sql
+++ b/synapse/storage/databases/main/schema/delta/19/event_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/20/dummy.sql b/synapse/storage/databases/main/schema/delta/20/dummy.sql
index e0ac49d1ec..e0ac49d1ec 100644
--- a/synapse/storage/data_stores/main/schema/delta/20/dummy.sql
+++ b/synapse/storage/databases/main/schema/delta/20/dummy.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/20/pushers.py b/synapse/storage/databases/main/schema/delta/20/pushers.py
index 3edfcfd783..3edfcfd783 100644
--- a/synapse/storage/data_stores/main/schema/delta/20/pushers.py
+++ b/synapse/storage/databases/main/schema/delta/20/pushers.py
diff --git a/synapse/storage/data_stores/main/schema/delta/21/end_to_end_keys.sql b/synapse/storage/databases/main/schema/delta/21/end_to_end_keys.sql
index 4c2fb20b77..4c2fb20b77 100644
--- a/synapse/storage/data_stores/main/schema/delta/21/end_to_end_keys.sql
+++ b/synapse/storage/databases/main/schema/delta/21/end_to_end_keys.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/21/receipts.sql b/synapse/storage/databases/main/schema/delta/21/receipts.sql
index d070845477..d070845477 100644
--- a/synapse/storage/data_stores/main/schema/delta/21/receipts.sql
+++ b/synapse/storage/databases/main/schema/delta/21/receipts.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/22/receipts_index.sql b/synapse/storage/databases/main/schema/delta/22/receipts_index.sql
index bfc0b3bcaa..bfc0b3bcaa 100644
--- a/synapse/storage/data_stores/main/schema/delta/22/receipts_index.sql
+++ b/synapse/storage/databases/main/schema/delta/22/receipts_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/22/user_threepids_unique.sql b/synapse/storage/databases/main/schema/delta/22/user_threepids_unique.sql
index 87edfa454c..87edfa454c 100644
--- a/synapse/storage/data_stores/main/schema/delta/22/user_threepids_unique.sql
+++ b/synapse/storage/databases/main/schema/delta/22/user_threepids_unique.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/24/stats_reporting.sql b/synapse/storage/databases/main/schema/delta/24/stats_reporting.sql
index acea7483bd..acea7483bd 100644
--- a/synapse/storage/data_stores/main/schema/delta/24/stats_reporting.sql
+++ b/synapse/storage/databases/main/schema/delta/24/stats_reporting.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/25/fts.py b/synapse/storage/databases/main/schema/delta/25/fts.py
index ee675e71ff..ee675e71ff 100644
--- a/synapse/storage/data_stores/main/schema/delta/25/fts.py
+++ b/synapse/storage/databases/main/schema/delta/25/fts.py
diff --git a/synapse/storage/data_stores/main/schema/delta/25/guest_access.sql b/synapse/storage/databases/main/schema/delta/25/guest_access.sql
index 1ea389b471..1ea389b471 100644
--- a/synapse/storage/data_stores/main/schema/delta/25/guest_access.sql
+++ b/synapse/storage/databases/main/schema/delta/25/guest_access.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/25/history_visibility.sql b/synapse/storage/databases/main/schema/delta/25/history_visibility.sql
index f468fc1897..f468fc1897 100644
--- a/synapse/storage/data_stores/main/schema/delta/25/history_visibility.sql
+++ b/synapse/storage/databases/main/schema/delta/25/history_visibility.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/25/tags.sql b/synapse/storage/databases/main/schema/delta/25/tags.sql
index 7a32ce68e4..7a32ce68e4 100644
--- a/synapse/storage/data_stores/main/schema/delta/25/tags.sql
+++ b/synapse/storage/databases/main/schema/delta/25/tags.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/26/account_data.sql b/synapse/storage/databases/main/schema/delta/26/account_data.sql
index e395de2b5e..e395de2b5e 100644
--- a/synapse/storage/data_stores/main/schema/delta/26/account_data.sql
+++ b/synapse/storage/databases/main/schema/delta/26/account_data.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/27/account_data.sql b/synapse/storage/databases/main/schema/delta/27/account_data.sql
index bf0558b5b3..bf0558b5b3 100644
--- a/synapse/storage/data_stores/main/schema/delta/27/account_data.sql
+++ b/synapse/storage/databases/main/schema/delta/27/account_data.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/27/forgotten_memberships.sql b/synapse/storage/databases/main/schema/delta/27/forgotten_memberships.sql
index e2094f37fe..e2094f37fe 100644
--- a/synapse/storage/data_stores/main/schema/delta/27/forgotten_memberships.sql
+++ b/synapse/storage/databases/main/schema/delta/27/forgotten_memberships.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/27/ts.py b/synapse/storage/databases/main/schema/delta/27/ts.py
index b7972cfa8e..b7972cfa8e 100644
--- a/synapse/storage/data_stores/main/schema/delta/27/ts.py
+++ b/synapse/storage/databases/main/schema/delta/27/ts.py
diff --git a/synapse/storage/data_stores/main/schema/delta/28/event_push_actions.sql b/synapse/storage/databases/main/schema/delta/28/event_push_actions.sql
index 4d519849df..4d519849df 100644
--- a/synapse/storage/data_stores/main/schema/delta/28/event_push_actions.sql
+++ b/synapse/storage/databases/main/schema/delta/28/event_push_actions.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/28/events_room_stream.sql b/synapse/storage/databases/main/schema/delta/28/events_room_stream.sql
index 36609475f1..36609475f1 100644
--- a/synapse/storage/data_stores/main/schema/delta/28/events_room_stream.sql
+++ b/synapse/storage/databases/main/schema/delta/28/events_room_stream.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/28/public_roms_index.sql b/synapse/storage/databases/main/schema/delta/28/public_roms_index.sql
index 6c1fd68c5b..6c1fd68c5b 100644
--- a/synapse/storage/data_stores/main/schema/delta/28/public_roms_index.sql
+++ b/synapse/storage/databases/main/schema/delta/28/public_roms_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/28/receipts_user_id_index.sql b/synapse/storage/databases/main/schema/delta/28/receipts_user_id_index.sql
index cb84c69baa..cb84c69baa 100644
--- a/synapse/storage/data_stores/main/schema/delta/28/receipts_user_id_index.sql
+++ b/synapse/storage/databases/main/schema/delta/28/receipts_user_id_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/28/upgrade_times.sql b/synapse/storage/databases/main/schema/delta/28/upgrade_times.sql
index 3e4a9ab455..3e4a9ab455 100644
--- a/synapse/storage/data_stores/main/schema/delta/28/upgrade_times.sql
+++ b/synapse/storage/databases/main/schema/delta/28/upgrade_times.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/28/users_is_guest.sql b/synapse/storage/databases/main/schema/delta/28/users_is_guest.sql
index 21d2b420bf..21d2b420bf 100644
--- a/synapse/storage/data_stores/main/schema/delta/28/users_is_guest.sql
+++ b/synapse/storage/databases/main/schema/delta/28/users_is_guest.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/29/push_actions.sql b/synapse/storage/databases/main/schema/delta/29/push_actions.sql
index 84b21cf813..84b21cf813 100644
--- a/synapse/storage/data_stores/main/schema/delta/29/push_actions.sql
+++ b/synapse/storage/databases/main/schema/delta/29/push_actions.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/30/alias_creator.sql b/synapse/storage/databases/main/schema/delta/30/alias_creator.sql
index c9d0dde638..c9d0dde638 100644
--- a/synapse/storage/data_stores/main/schema/delta/30/alias_creator.sql
+++ b/synapse/storage/databases/main/schema/delta/30/alias_creator.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/30/as_users.py b/synapse/storage/databases/main/schema/delta/30/as_users.py
index b42c02710a..b42c02710a 100644
--- a/synapse/storage/data_stores/main/schema/delta/30/as_users.py
+++ b/synapse/storage/databases/main/schema/delta/30/as_users.py
diff --git a/synapse/storage/data_stores/main/schema/delta/30/deleted_pushers.sql b/synapse/storage/databases/main/schema/delta/30/deleted_pushers.sql
index 712c454aa1..712c454aa1 100644
--- a/synapse/storage/data_stores/main/schema/delta/30/deleted_pushers.sql
+++ b/synapse/storage/databases/main/schema/delta/30/deleted_pushers.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/30/presence_stream.sql b/synapse/storage/databases/main/schema/delta/30/presence_stream.sql
index 606bbb037d..606bbb037d 100644
--- a/synapse/storage/data_stores/main/schema/delta/30/presence_stream.sql
+++ b/synapse/storage/databases/main/schema/delta/30/presence_stream.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/30/public_rooms.sql b/synapse/storage/databases/main/schema/delta/30/public_rooms.sql
index f09db4faa6..f09db4faa6 100644
--- a/synapse/storage/data_stores/main/schema/delta/30/public_rooms.sql
+++ b/synapse/storage/databases/main/schema/delta/30/public_rooms.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/30/push_rule_stream.sql b/synapse/storage/databases/main/schema/delta/30/push_rule_stream.sql
index 735aa8d5f6..735aa8d5f6 100644
--- a/synapse/storage/data_stores/main/schema/delta/30/push_rule_stream.sql
+++ b/synapse/storage/databases/main/schema/delta/30/push_rule_stream.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/30/threepid_guest_access_tokens.sql b/synapse/storage/databases/main/schema/delta/30/threepid_guest_access_tokens.sql
index 0dd2f1360c..0dd2f1360c 100644
--- a/synapse/storage/data_stores/main/schema/delta/30/threepid_guest_access_tokens.sql
+++ b/synapse/storage/databases/main/schema/delta/30/threepid_guest_access_tokens.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/31/invites.sql b/synapse/storage/databases/main/schema/delta/31/invites.sql
index 2c57846d5a..2c57846d5a 100644
--- a/synapse/storage/data_stores/main/schema/delta/31/invites.sql
+++ b/synapse/storage/databases/main/schema/delta/31/invites.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/31/local_media_repository_url_cache.sql b/synapse/storage/databases/main/schema/delta/31/local_media_repository_url_cache.sql
index 9efb4280eb..9efb4280eb 100644
--- a/synapse/storage/data_stores/main/schema/delta/31/local_media_repository_url_cache.sql
+++ b/synapse/storage/databases/main/schema/delta/31/local_media_repository_url_cache.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/31/pushers.py b/synapse/storage/databases/main/schema/delta/31/pushers.py
index 9bb504aad5..9bb504aad5 100644
--- a/synapse/storage/data_stores/main/schema/delta/31/pushers.py
+++ b/synapse/storage/databases/main/schema/delta/31/pushers.py
diff --git a/synapse/storage/data_stores/main/schema/delta/31/pushers_index.sql b/synapse/storage/databases/main/schema/delta/31/pushers_index.sql
index a82add88fd..a82add88fd 100644
--- a/synapse/storage/data_stores/main/schema/delta/31/pushers_index.sql
+++ b/synapse/storage/databases/main/schema/delta/31/pushers_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/31/search_update.py b/synapse/storage/databases/main/schema/delta/31/search_update.py
index 63b757ade6..63b757ade6 100644
--- a/synapse/storage/data_stores/main/schema/delta/31/search_update.py
+++ b/synapse/storage/databases/main/schema/delta/31/search_update.py
diff --git a/synapse/storage/data_stores/main/schema/delta/32/events.sql b/synapse/storage/databases/main/schema/delta/32/events.sql
index 1dd0f9e170..1dd0f9e170 100644
--- a/synapse/storage/data_stores/main/schema/delta/32/events.sql
+++ b/synapse/storage/databases/main/schema/delta/32/events.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/32/openid.sql b/synapse/storage/databases/main/schema/delta/32/openid.sql
index 36f37b11c8..36f37b11c8 100644
--- a/synapse/storage/data_stores/main/schema/delta/32/openid.sql
+++ b/synapse/storage/databases/main/schema/delta/32/openid.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/32/pusher_throttle.sql b/synapse/storage/databases/main/schema/delta/32/pusher_throttle.sql
index d86d30c13c..d86d30c13c 100644
--- a/synapse/storage/data_stores/main/schema/delta/32/pusher_throttle.sql
+++ b/synapse/storage/databases/main/schema/delta/32/pusher_throttle.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/32/remove_indices.sql b/synapse/storage/databases/main/schema/delta/32/remove_indices.sql
index 2de50d408c..2de50d408c 100644
--- a/synapse/storage/data_stores/main/schema/delta/32/remove_indices.sql
+++ b/synapse/storage/databases/main/schema/delta/32/remove_indices.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/32/reports.sql b/synapse/storage/databases/main/schema/delta/32/reports.sql
index d13609776f..d13609776f 100644
--- a/synapse/storage/data_stores/main/schema/delta/32/reports.sql
+++ b/synapse/storage/databases/main/schema/delta/32/reports.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/33/access_tokens_device_index.sql b/synapse/storage/databases/main/schema/delta/33/access_tokens_device_index.sql
index 61ad3fe3e8..61ad3fe3e8 100644
--- a/synapse/storage/data_stores/main/schema/delta/33/access_tokens_device_index.sql
+++ b/synapse/storage/databases/main/schema/delta/33/access_tokens_device_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/33/devices.sql b/synapse/storage/databases/main/schema/delta/33/devices.sql
index eca7268d82..eca7268d82 100644
--- a/synapse/storage/data_stores/main/schema/delta/33/devices.sql
+++ b/synapse/storage/databases/main/schema/delta/33/devices.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/33/devices_for_e2e_keys.sql b/synapse/storage/databases/main/schema/delta/33/devices_for_e2e_keys.sql
index aa4a3b9f2f..aa4a3b9f2f 100644
--- a/synapse/storage/data_stores/main/schema/delta/33/devices_for_e2e_keys.sql
+++ b/synapse/storage/databases/main/schema/delta/33/devices_for_e2e_keys.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql b/synapse/storage/databases/main/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql
index 6671573398..6671573398 100644
--- a/synapse/storage/data_stores/main/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql
+++ b/synapse/storage/databases/main/schema/delta/33/devices_for_e2e_keys_clear_unknown_device.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/33/event_fields.py b/synapse/storage/databases/main/schema/delta/33/event_fields.py
index a3e81eeac7..a3e81eeac7 100644
--- a/synapse/storage/data_stores/main/schema/delta/33/event_fields.py
+++ b/synapse/storage/databases/main/schema/delta/33/event_fields.py
diff --git a/synapse/storage/data_stores/main/schema/delta/33/remote_media_ts.py b/synapse/storage/databases/main/schema/delta/33/remote_media_ts.py
index a26057dfb6..a26057dfb6 100644
--- a/synapse/storage/data_stores/main/schema/delta/33/remote_media_ts.py
+++ b/synapse/storage/databases/main/schema/delta/33/remote_media_ts.py
diff --git a/synapse/storage/data_stores/main/schema/delta/33/user_ips_index.sql b/synapse/storage/databases/main/schema/delta/33/user_ips_index.sql
index 473f75a78e..473f75a78e 100644
--- a/synapse/storage/data_stores/main/schema/delta/33/user_ips_index.sql
+++ b/synapse/storage/databases/main/schema/delta/33/user_ips_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/34/appservice_stream.sql b/synapse/storage/databases/main/schema/delta/34/appservice_stream.sql
index 69e16eda0f..69e16eda0f 100644
--- a/synapse/storage/data_stores/main/schema/delta/34/appservice_stream.sql
+++ b/synapse/storage/databases/main/schema/delta/34/appservice_stream.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/34/cache_stream.py b/synapse/storage/databases/main/schema/delta/34/cache_stream.py
index cf09e43e2b..cf09e43e2b 100644
--- a/synapse/storage/data_stores/main/schema/delta/34/cache_stream.py
+++ b/synapse/storage/databases/main/schema/delta/34/cache_stream.py
diff --git a/synapse/storage/data_stores/main/schema/delta/34/device_inbox.sql b/synapse/storage/databases/main/schema/delta/34/device_inbox.sql
index e68844c74a..e68844c74a 100644
--- a/synapse/storage/data_stores/main/schema/delta/34/device_inbox.sql
+++ b/synapse/storage/databases/main/schema/delta/34/device_inbox.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/34/push_display_name_rename.sql b/synapse/storage/databases/main/schema/delta/34/push_display_name_rename.sql
index 0d9fe1a99a..0d9fe1a99a 100644
--- a/synapse/storage/data_stores/main/schema/delta/34/push_display_name_rename.sql
+++ b/synapse/storage/databases/main/schema/delta/34/push_display_name_rename.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/34/received_txn_purge.py b/synapse/storage/databases/main/schema/delta/34/received_txn_purge.py
index 67d505e68b..67d505e68b 100644
--- a/synapse/storage/data_stores/main/schema/delta/34/received_txn_purge.py
+++ b/synapse/storage/databases/main/schema/delta/34/received_txn_purge.py
diff --git a/synapse/storage/data_stores/main/schema/delta/35/contains_url.sql b/synapse/storage/databases/main/schema/delta/35/contains_url.sql
index 6cd123027b..6cd123027b 100644
--- a/synapse/storage/data_stores/main/schema/delta/35/contains_url.sql
+++ b/synapse/storage/databases/main/schema/delta/35/contains_url.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/35/device_outbox.sql b/synapse/storage/databases/main/schema/delta/35/device_outbox.sql
index 17e6c43105..17e6c43105 100644
--- a/synapse/storage/data_stores/main/schema/delta/35/device_outbox.sql
+++ b/synapse/storage/databases/main/schema/delta/35/device_outbox.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/35/device_stream_id.sql b/synapse/storage/databases/main/schema/delta/35/device_stream_id.sql
index 7ab7d942e2..7ab7d942e2 100644
--- a/synapse/storage/data_stores/main/schema/delta/35/device_stream_id.sql
+++ b/synapse/storage/databases/main/schema/delta/35/device_stream_id.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/35/event_push_actions_index.sql b/synapse/storage/databases/main/schema/delta/35/event_push_actions_index.sql
index 2e836d8e9c..2e836d8e9c 100644
--- a/synapse/storage/data_stores/main/schema/delta/35/event_push_actions_index.sql
+++ b/synapse/storage/databases/main/schema/delta/35/event_push_actions_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/35/public_room_list_change_stream.sql b/synapse/storage/databases/main/schema/delta/35/public_room_list_change_stream.sql
index dd2bf2e28a..dd2bf2e28a 100644
--- a/synapse/storage/data_stores/main/schema/delta/35/public_room_list_change_stream.sql
+++ b/synapse/storage/databases/main/schema/delta/35/public_room_list_change_stream.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/35/stream_order_to_extrem.sql b/synapse/storage/databases/main/schema/delta/35/stream_order_to_extrem.sql
index 2b945d8a57..2b945d8a57 100644
--- a/synapse/storage/data_stores/main/schema/delta/35/stream_order_to_extrem.sql
+++ b/synapse/storage/databases/main/schema/delta/35/stream_order_to_extrem.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/36/readd_public_rooms.sql b/synapse/storage/databases/main/schema/delta/36/readd_public_rooms.sql
index 90d8fd18f9..90d8fd18f9 100644
--- a/synapse/storage/data_stores/main/schema/delta/36/readd_public_rooms.sql
+++ b/synapse/storage/databases/main/schema/delta/36/readd_public_rooms.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/37/remove_auth_idx.py b/synapse/storage/databases/main/schema/delta/37/remove_auth_idx.py
index a377884169..a377884169 100644
--- a/synapse/storage/data_stores/main/schema/delta/37/remove_auth_idx.py
+++ b/synapse/storage/databases/main/schema/delta/37/remove_auth_idx.py
diff --git a/synapse/storage/data_stores/main/schema/delta/37/user_threepids.sql b/synapse/storage/databases/main/schema/delta/37/user_threepids.sql
index cf7a90dd10..cf7a90dd10 100644
--- a/synapse/storage/data_stores/main/schema/delta/37/user_threepids.sql
+++ b/synapse/storage/databases/main/schema/delta/37/user_threepids.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/38/postgres_fts_gist.sql b/synapse/storage/databases/main/schema/delta/38/postgres_fts_gist.sql
index 515e6b8e84..515e6b8e84 100644
--- a/synapse/storage/data_stores/main/schema/delta/38/postgres_fts_gist.sql
+++ b/synapse/storage/databases/main/schema/delta/38/postgres_fts_gist.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/39/appservice_room_list.sql b/synapse/storage/databases/main/schema/delta/39/appservice_room_list.sql
index 74bdc49073..74bdc49073 100644
--- a/synapse/storage/data_stores/main/schema/delta/39/appservice_room_list.sql
+++ b/synapse/storage/databases/main/schema/delta/39/appservice_room_list.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/39/device_federation_stream_idx.sql b/synapse/storage/databases/main/schema/delta/39/device_federation_stream_idx.sql
index 00be801e90..00be801e90 100644
--- a/synapse/storage/data_stores/main/schema/delta/39/device_federation_stream_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/39/device_federation_stream_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/39/event_push_index.sql b/synapse/storage/databases/main/schema/delta/39/event_push_index.sql
index de2ad93e5c..de2ad93e5c 100644
--- a/synapse/storage/data_stores/main/schema/delta/39/event_push_index.sql
+++ b/synapse/storage/databases/main/schema/delta/39/event_push_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/39/federation_out_position.sql b/synapse/storage/databases/main/schema/delta/39/federation_out_position.sql
index 5af814290b..5af814290b 100644
--- a/synapse/storage/data_stores/main/schema/delta/39/federation_out_position.sql
+++ b/synapse/storage/databases/main/schema/delta/39/federation_out_position.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/39/membership_profile.sql b/synapse/storage/databases/main/schema/delta/39/membership_profile.sql
index 1bf911c8ab..1bf911c8ab 100644
--- a/synapse/storage/data_stores/main/schema/delta/39/membership_profile.sql
+++ b/synapse/storage/databases/main/schema/delta/39/membership_profile.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/40/current_state_idx.sql b/synapse/storage/databases/main/schema/delta/40/current_state_idx.sql
index 7ffa189f39..7ffa189f39 100644
--- a/synapse/storage/data_stores/main/schema/delta/40/current_state_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/40/current_state_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/40/device_inbox.sql b/synapse/storage/databases/main/schema/delta/40/device_inbox.sql
index b9fe1f0480..b9fe1f0480 100644
--- a/synapse/storage/data_stores/main/schema/delta/40/device_inbox.sql
+++ b/synapse/storage/databases/main/schema/delta/40/device_inbox.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/40/device_list_streams.sql b/synapse/storage/databases/main/schema/delta/40/device_list_streams.sql
index dd6dcb65f1..dd6dcb65f1 100644
--- a/synapse/storage/data_stores/main/schema/delta/40/device_list_streams.sql
+++ b/synapse/storage/databases/main/schema/delta/40/device_list_streams.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/40/event_push_summary.sql b/synapse/storage/databases/main/schema/delta/40/event_push_summary.sql
index 3918f0b794..3918f0b794 100644
--- a/synapse/storage/data_stores/main/schema/delta/40/event_push_summary.sql
+++ b/synapse/storage/databases/main/schema/delta/40/event_push_summary.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/40/pushers.sql b/synapse/storage/databases/main/schema/delta/40/pushers.sql
index 054a223f14..054a223f14 100644
--- a/synapse/storage/data_stores/main/schema/delta/40/pushers.sql
+++ b/synapse/storage/databases/main/schema/delta/40/pushers.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/41/device_list_stream_idx.sql b/synapse/storage/databases/main/schema/delta/41/device_list_stream_idx.sql
index b7bee8b692..b7bee8b692 100644
--- a/synapse/storage/data_stores/main/schema/delta/41/device_list_stream_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/41/device_list_stream_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/41/device_outbound_index.sql b/synapse/storage/databases/main/schema/delta/41/device_outbound_index.sql
index 62f0b9892b..62f0b9892b 100644
--- a/synapse/storage/data_stores/main/schema/delta/41/device_outbound_index.sql
+++ b/synapse/storage/databases/main/schema/delta/41/device_outbound_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/41/event_search_event_id_idx.sql b/synapse/storage/databases/main/schema/delta/41/event_search_event_id_idx.sql
index 5d9cfecf36..5d9cfecf36 100644
--- a/synapse/storage/data_stores/main/schema/delta/41/event_search_event_id_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/41/event_search_event_id_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/41/ratelimit.sql b/synapse/storage/databases/main/schema/delta/41/ratelimit.sql
index a194bf0238..a194bf0238 100644
--- a/synapse/storage/data_stores/main/schema/delta/41/ratelimit.sql
+++ b/synapse/storage/databases/main/schema/delta/41/ratelimit.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/42/current_state_delta.sql b/synapse/storage/databases/main/schema/delta/42/current_state_delta.sql
index d28851aff8..d28851aff8 100644
--- a/synapse/storage/data_stores/main/schema/delta/42/current_state_delta.sql
+++ b/synapse/storage/databases/main/schema/delta/42/current_state_delta.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/42/device_list_last_id.sql b/synapse/storage/databases/main/schema/delta/42/device_list_last_id.sql
index 9ab8c14fa3..9ab8c14fa3 100644
--- a/synapse/storage/data_stores/main/schema/delta/42/device_list_last_id.sql
+++ b/synapse/storage/databases/main/schema/delta/42/device_list_last_id.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/42/event_auth_state_only.sql b/synapse/storage/databases/main/schema/delta/42/event_auth_state_only.sql
index b8821ac759..b8821ac759 100644
--- a/synapse/storage/data_stores/main/schema/delta/42/event_auth_state_only.sql
+++ b/synapse/storage/databases/main/schema/delta/42/event_auth_state_only.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/42/user_dir.py b/synapse/storage/databases/main/schema/delta/42/user_dir.py
index 506f326f4d..506f326f4d 100644
--- a/synapse/storage/data_stores/main/schema/delta/42/user_dir.py
+++ b/synapse/storage/databases/main/schema/delta/42/user_dir.py
diff --git a/synapse/storage/data_stores/main/schema/delta/43/blocked_rooms.sql b/synapse/storage/databases/main/schema/delta/43/blocked_rooms.sql
index 0e3cd143ff..0e3cd143ff 100644
--- a/synapse/storage/data_stores/main/schema/delta/43/blocked_rooms.sql
+++ b/synapse/storage/databases/main/schema/delta/43/blocked_rooms.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/43/quarantine_media.sql b/synapse/storage/databases/main/schema/delta/43/quarantine_media.sql
index 630907ec4f..630907ec4f 100644
--- a/synapse/storage/data_stores/main/schema/delta/43/quarantine_media.sql
+++ b/synapse/storage/databases/main/schema/delta/43/quarantine_media.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/43/url_cache.sql b/synapse/storage/databases/main/schema/delta/43/url_cache.sql
index 45ebe020da..45ebe020da 100644
--- a/synapse/storage/data_stores/main/schema/delta/43/url_cache.sql
+++ b/synapse/storage/databases/main/schema/delta/43/url_cache.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/43/user_share.sql b/synapse/storage/databases/main/schema/delta/43/user_share.sql
index ee7062abe4..ee7062abe4 100644
--- a/synapse/storage/data_stores/main/schema/delta/43/user_share.sql
+++ b/synapse/storage/databases/main/schema/delta/43/user_share.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/44/expire_url_cache.sql b/synapse/storage/databases/main/schema/delta/44/expire_url_cache.sql
index b12f9b2ebf..b12f9b2ebf 100644
--- a/synapse/storage/data_stores/main/schema/delta/44/expire_url_cache.sql
+++ b/synapse/storage/databases/main/schema/delta/44/expire_url_cache.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/45/group_server.sql b/synapse/storage/databases/main/schema/delta/45/group_server.sql
index b2333848a0..b2333848a0 100644
--- a/synapse/storage/data_stores/main/schema/delta/45/group_server.sql
+++ b/synapse/storage/databases/main/schema/delta/45/group_server.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/45/profile_cache.sql b/synapse/storage/databases/main/schema/delta/45/profile_cache.sql
index e5ddc84df0..e5ddc84df0 100644
--- a/synapse/storage/data_stores/main/schema/delta/45/profile_cache.sql
+++ b/synapse/storage/databases/main/schema/delta/45/profile_cache.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/46/drop_refresh_tokens.sql b/synapse/storage/databases/main/schema/delta/46/drop_refresh_tokens.sql
index 68c48a89a9..68c48a89a9 100644
--- a/synapse/storage/data_stores/main/schema/delta/46/drop_refresh_tokens.sql
+++ b/synapse/storage/databases/main/schema/delta/46/drop_refresh_tokens.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/46/drop_unique_deleted_pushers.sql b/synapse/storage/databases/main/schema/delta/46/drop_unique_deleted_pushers.sql
index bb307889c1..bb307889c1 100644
--- a/synapse/storage/data_stores/main/schema/delta/46/drop_unique_deleted_pushers.sql
+++ b/synapse/storage/databases/main/schema/delta/46/drop_unique_deleted_pushers.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/46/group_server.sql b/synapse/storage/databases/main/schema/delta/46/group_server.sql
index 097679bc9a..097679bc9a 100644
--- a/synapse/storage/data_stores/main/schema/delta/46/group_server.sql
+++ b/synapse/storage/databases/main/schema/delta/46/group_server.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/46/local_media_repository_url_idx.sql b/synapse/storage/databases/main/schema/delta/46/local_media_repository_url_idx.sql
index bbfc7f5d1a..bbfc7f5d1a 100644
--- a/synapse/storage/data_stores/main/schema/delta/46/local_media_repository_url_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/46/local_media_repository_url_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/46/user_dir_null_room_ids.sql b/synapse/storage/databases/main/schema/delta/46/user_dir_null_room_ids.sql
index cb0d5a2576..cb0d5a2576 100644
--- a/synapse/storage/data_stores/main/schema/delta/46/user_dir_null_room_ids.sql
+++ b/synapse/storage/databases/main/schema/delta/46/user_dir_null_room_ids.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/46/user_dir_typos.sql b/synapse/storage/databases/main/schema/delta/46/user_dir_typos.sql
index d9505f8da1..d9505f8da1 100644
--- a/synapse/storage/data_stores/main/schema/delta/46/user_dir_typos.sql
+++ b/synapse/storage/databases/main/schema/delta/46/user_dir_typos.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/47/last_access_media.sql b/synapse/storage/databases/main/schema/delta/47/last_access_media.sql
index f505fb22b5..f505fb22b5 100644
--- a/synapse/storage/data_stores/main/schema/delta/47/last_access_media.sql
+++ b/synapse/storage/databases/main/schema/delta/47/last_access_media.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/47/postgres_fts_gin.sql b/synapse/storage/databases/main/schema/delta/47/postgres_fts_gin.sql
index 31d7a817eb..31d7a817eb 100644
--- a/synapse/storage/data_stores/main/schema/delta/47/postgres_fts_gin.sql
+++ b/synapse/storage/databases/main/schema/delta/47/postgres_fts_gin.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/47/push_actions_staging.sql b/synapse/storage/databases/main/schema/delta/47/push_actions_staging.sql
index edccf4a96f..edccf4a96f 100644
--- a/synapse/storage/data_stores/main/schema/delta/47/push_actions_staging.sql
+++ b/synapse/storage/databases/main/schema/delta/47/push_actions_staging.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/48/add_user_consent.sql b/synapse/storage/databases/main/schema/delta/48/add_user_consent.sql
index 5237491506..5237491506 100644
--- a/synapse/storage/data_stores/main/schema/delta/48/add_user_consent.sql
+++ b/synapse/storage/databases/main/schema/delta/48/add_user_consent.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/48/add_user_ips_last_seen_index.sql b/synapse/storage/databases/main/schema/delta/48/add_user_ips_last_seen_index.sql
index 9248b0b24a..9248b0b24a 100644
--- a/synapse/storage/data_stores/main/schema/delta/48/add_user_ips_last_seen_index.sql
+++ b/synapse/storage/databases/main/schema/delta/48/add_user_ips_last_seen_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/48/deactivated_users.sql b/synapse/storage/databases/main/schema/delta/48/deactivated_users.sql
index e9013a6969..e9013a6969 100644
--- a/synapse/storage/data_stores/main/schema/delta/48/deactivated_users.sql
+++ b/synapse/storage/databases/main/schema/delta/48/deactivated_users.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/48/group_unique_indexes.py b/synapse/storage/databases/main/schema/delta/48/group_unique_indexes.py
index 49f5f2c003..49f5f2c003 100644
--- a/synapse/storage/data_stores/main/schema/delta/48/group_unique_indexes.py
+++ b/synapse/storage/databases/main/schema/delta/48/group_unique_indexes.py
diff --git a/synapse/storage/data_stores/main/schema/delta/48/groups_joinable.sql b/synapse/storage/databases/main/schema/delta/48/groups_joinable.sql
index ce26eaf0c9..ce26eaf0c9 100644
--- a/synapse/storage/data_stores/main/schema/delta/48/groups_joinable.sql
+++ b/synapse/storage/databases/main/schema/delta/48/groups_joinable.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/49/add_user_consent_server_notice_sent.sql b/synapse/storage/databases/main/schema/delta/49/add_user_consent_server_notice_sent.sql
index 14dcf18d73..14dcf18d73 100644
--- a/synapse/storage/data_stores/main/schema/delta/49/add_user_consent_server_notice_sent.sql
+++ b/synapse/storage/databases/main/schema/delta/49/add_user_consent_server_notice_sent.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/49/add_user_daily_visits.sql b/synapse/storage/databases/main/schema/delta/49/add_user_daily_visits.sql
index 3dd478196f..3dd478196f 100644
--- a/synapse/storage/data_stores/main/schema/delta/49/add_user_daily_visits.sql
+++ b/synapse/storage/databases/main/schema/delta/49/add_user_daily_visits.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/49/add_user_ips_last_seen_only_index.sql b/synapse/storage/databases/main/schema/delta/49/add_user_ips_last_seen_only_index.sql
index 3a4ed59b5b..3a4ed59b5b 100644
--- a/synapse/storage/data_stores/main/schema/delta/49/add_user_ips_last_seen_only_index.sql
+++ b/synapse/storage/databases/main/schema/delta/49/add_user_ips_last_seen_only_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/50/add_creation_ts_users_index.sql b/synapse/storage/databases/main/schema/delta/50/add_creation_ts_users_index.sql
index c93ae47532..c93ae47532 100644
--- a/synapse/storage/data_stores/main/schema/delta/50/add_creation_ts_users_index.sql
+++ b/synapse/storage/databases/main/schema/delta/50/add_creation_ts_users_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/50/erasure_store.sql b/synapse/storage/databases/main/schema/delta/50/erasure_store.sql
index 5d8641a9ab..5d8641a9ab 100644
--- a/synapse/storage/data_stores/main/schema/delta/50/erasure_store.sql
+++ b/synapse/storage/databases/main/schema/delta/50/erasure_store.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/50/make_event_content_nullable.py b/synapse/storage/databases/main/schema/delta/50/make_event_content_nullable.py
index b1684a8441..b1684a8441 100644
--- a/synapse/storage/data_stores/main/schema/delta/50/make_event_content_nullable.py
+++ b/synapse/storage/databases/main/schema/delta/50/make_event_content_nullable.py
diff --git a/synapse/storage/data_stores/main/schema/delta/51/e2e_room_keys.sql b/synapse/storage/databases/main/schema/delta/51/e2e_room_keys.sql
index c0e66a697d..c0e66a697d 100644
--- a/synapse/storage/data_stores/main/schema/delta/51/e2e_room_keys.sql
+++ b/synapse/storage/databases/main/schema/delta/51/e2e_room_keys.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/51/monthly_active_users.sql b/synapse/storage/databases/main/schema/delta/51/monthly_active_users.sql
index c9d537d5a3..c9d537d5a3 100644
--- a/synapse/storage/data_stores/main/schema/delta/51/monthly_active_users.sql
+++ b/synapse/storage/databases/main/schema/delta/51/monthly_active_users.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/52/add_event_to_state_group_index.sql b/synapse/storage/databases/main/schema/delta/52/add_event_to_state_group_index.sql
index 91e03d13e1..91e03d13e1 100644
--- a/synapse/storage/data_stores/main/schema/delta/52/add_event_to_state_group_index.sql
+++ b/synapse/storage/databases/main/schema/delta/52/add_event_to_state_group_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/52/device_list_streams_unique_idx.sql b/synapse/storage/databases/main/schema/delta/52/device_list_streams_unique_idx.sql
index bfa49e6f92..bfa49e6f92 100644
--- a/synapse/storage/data_stores/main/schema/delta/52/device_list_streams_unique_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/52/device_list_streams_unique_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/52/e2e_room_keys.sql b/synapse/storage/databases/main/schema/delta/52/e2e_room_keys.sql
index db687cccae..db687cccae 100644
--- a/synapse/storage/data_stores/main/schema/delta/52/e2e_room_keys.sql
+++ b/synapse/storage/databases/main/schema/delta/52/e2e_room_keys.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/add_user_type_to_users.sql b/synapse/storage/databases/main/schema/delta/53/add_user_type_to_users.sql
index 88ec2f83e5..88ec2f83e5 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/add_user_type_to_users.sql
+++ b/synapse/storage/databases/main/schema/delta/53/add_user_type_to_users.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/drop_sent_transactions.sql b/synapse/storage/databases/main/schema/delta/53/drop_sent_transactions.sql
index e372f5a44a..e372f5a44a 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/drop_sent_transactions.sql
+++ b/synapse/storage/databases/main/schema/delta/53/drop_sent_transactions.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/event_format_version.sql b/synapse/storage/databases/main/schema/delta/53/event_format_version.sql
index 1d977c2834..1d977c2834 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/event_format_version.sql
+++ b/synapse/storage/databases/main/schema/delta/53/event_format_version.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/user_dir_populate.sql b/synapse/storage/databases/main/schema/delta/53/user_dir_populate.sql
index ffcc896b58..ffcc896b58 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/user_dir_populate.sql
+++ b/synapse/storage/databases/main/schema/delta/53/user_dir_populate.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/user_ips_index.sql b/synapse/storage/databases/main/schema/delta/53/user_ips_index.sql
index b812c5794f..b812c5794f 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/user_ips_index.sql
+++ b/synapse/storage/databases/main/schema/delta/53/user_ips_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/user_share.sql b/synapse/storage/databases/main/schema/delta/53/user_share.sql
index 5831b1a6f8..5831b1a6f8 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/user_share.sql
+++ b/synapse/storage/databases/main/schema/delta/53/user_share.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/user_threepid_id.sql b/synapse/storage/databases/main/schema/delta/53/user_threepid_id.sql
index 80c2c573b6..80c2c573b6 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/user_threepid_id.sql
+++ b/synapse/storage/databases/main/schema/delta/53/user_threepid_id.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/53/users_in_public_rooms.sql b/synapse/storage/databases/main/schema/delta/53/users_in_public_rooms.sql
index f7827ca6d2..f7827ca6d2 100644
--- a/synapse/storage/data_stores/main/schema/delta/53/users_in_public_rooms.sql
+++ b/synapse/storage/databases/main/schema/delta/53/users_in_public_rooms.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/account_validity_with_renewal.sql b/synapse/storage/databases/main/schema/delta/54/account_validity_with_renewal.sql
index 0adb2ad55e..0adb2ad55e 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/account_validity_with_renewal.sql
+++ b/synapse/storage/databases/main/schema/delta/54/account_validity_with_renewal.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/add_validity_to_server_keys.sql b/synapse/storage/databases/main/schema/delta/54/add_validity_to_server_keys.sql
index c01aa9d2d9..c01aa9d2d9 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/add_validity_to_server_keys.sql
+++ b/synapse/storage/databases/main/schema/delta/54/add_validity_to_server_keys.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/delete_forward_extremities.sql b/synapse/storage/databases/main/schema/delta/54/delete_forward_extremities.sql
index b062ec840c..b062ec840c 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/delete_forward_extremities.sql
+++ b/synapse/storage/databases/main/schema/delta/54/delete_forward_extremities.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/drop_legacy_tables.sql b/synapse/storage/databases/main/schema/delta/54/drop_legacy_tables.sql
index dbbe682697..dbbe682697 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/drop_legacy_tables.sql
+++ b/synapse/storage/databases/main/schema/delta/54/drop_legacy_tables.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/drop_presence_list.sql b/synapse/storage/databases/main/schema/delta/54/drop_presence_list.sql
index e6ee70c623..e6ee70c623 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/drop_presence_list.sql
+++ b/synapse/storage/databases/main/schema/delta/54/drop_presence_list.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/relations.sql b/synapse/storage/databases/main/schema/delta/54/relations.sql
index 134862b870..134862b870 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/relations.sql
+++ b/synapse/storage/databases/main/schema/delta/54/relations.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/stats.sql b/synapse/storage/databases/main/schema/delta/54/stats.sql
index 652e58308e..652e58308e 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/stats.sql
+++ b/synapse/storage/databases/main/schema/delta/54/stats.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/54/stats2.sql b/synapse/storage/databases/main/schema/delta/54/stats2.sql
index 3b2d48447f..3b2d48447f 100644
--- a/synapse/storage/data_stores/main/schema/delta/54/stats2.sql
+++ b/synapse/storage/databases/main/schema/delta/54/stats2.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/55/access_token_expiry.sql b/synapse/storage/databases/main/schema/delta/55/access_token_expiry.sql
index 4590604bfd..4590604bfd 100644
--- a/synapse/storage/data_stores/main/schema/delta/55/access_token_expiry.sql
+++ b/synapse/storage/databases/main/schema/delta/55/access_token_expiry.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/55/track_threepid_validations.sql b/synapse/storage/databases/main/schema/delta/55/track_threepid_validations.sql
index a8eced2e0a..a8eced2e0a 100644
--- a/synapse/storage/data_stores/main/schema/delta/55/track_threepid_validations.sql
+++ b/synapse/storage/databases/main/schema/delta/55/track_threepid_validations.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/55/users_alter_deactivated.sql b/synapse/storage/databases/main/schema/delta/55/users_alter_deactivated.sql
index dabdde489b..dabdde489b 100644
--- a/synapse/storage/data_stores/main/schema/delta/55/users_alter_deactivated.sql
+++ b/synapse/storage/databases/main/schema/delta/55/users_alter_deactivated.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/add_spans_to_device_lists.sql b/synapse/storage/databases/main/schema/delta/56/add_spans_to_device_lists.sql
index 41807eb1e7..41807eb1e7 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/add_spans_to_device_lists.sql
+++ b/synapse/storage/databases/main/schema/delta/56/add_spans_to_device_lists.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/current_state_events_membership.sql b/synapse/storage/databases/main/schema/delta/56/current_state_events_membership.sql
index 473018676f..473018676f 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/current_state_events_membership.sql
+++ b/synapse/storage/databases/main/schema/delta/56/current_state_events_membership.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/current_state_events_membership_mk2.sql b/synapse/storage/databases/main/schema/delta/56/current_state_events_membership_mk2.sql
index 3133d42d4a..3133d42d4a 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/current_state_events_membership_mk2.sql
+++ b/synapse/storage/databases/main/schema/delta/56/current_state_events_membership_mk2.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/delete_keys_from_deleted_backups.sql b/synapse/storage/databases/main/schema/delta/56/delete_keys_from_deleted_backups.sql
index 1d2ddb1b1a..1d2ddb1b1a 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/delete_keys_from_deleted_backups.sql
+++ b/synapse/storage/databases/main/schema/delta/56/delete_keys_from_deleted_backups.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/destinations_failure_ts.sql b/synapse/storage/databases/main/schema/delta/56/destinations_failure_ts.sql
index f00889290b..f00889290b 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/destinations_failure_ts.sql
+++ b/synapse/storage/databases/main/schema/delta/56/destinations_failure_ts.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/destinations_retry_interval_type.sql.postgres b/synapse/storage/databases/main/schema/delta/56/destinations_retry_interval_type.sql.postgres
index b9bbb18a91..b9bbb18a91 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/destinations_retry_interval_type.sql.postgres
+++ b/synapse/storage/databases/main/schema/delta/56/destinations_retry_interval_type.sql.postgres
diff --git a/synapse/storage/data_stores/main/schema/delta/56/device_stream_id_insert.sql b/synapse/storage/databases/main/schema/delta/56/device_stream_id_insert.sql
index c2f557fde9..c2f557fde9 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/device_stream_id_insert.sql
+++ b/synapse/storage/databases/main/schema/delta/56/device_stream_id_insert.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/devices_last_seen.sql b/synapse/storage/databases/main/schema/delta/56/devices_last_seen.sql
index dfa902d0ba..dfa902d0ba 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/devices_last_seen.sql
+++ b/synapse/storage/databases/main/schema/delta/56/devices_last_seen.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/drop_unused_event_tables.sql b/synapse/storage/databases/main/schema/delta/56/drop_unused_event_tables.sql
index 9f09922c67..9f09922c67 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/drop_unused_event_tables.sql
+++ b/synapse/storage/databases/main/schema/delta/56/drop_unused_event_tables.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/event_expiry.sql b/synapse/storage/databases/main/schema/delta/56/event_expiry.sql
index 81a36a8b1d..81a36a8b1d 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/event_expiry.sql
+++ b/synapse/storage/databases/main/schema/delta/56/event_expiry.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/event_labels.sql b/synapse/storage/databases/main/schema/delta/56/event_labels.sql
index 5e29c1da19..5e29c1da19 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/event_labels.sql
+++ b/synapse/storage/databases/main/schema/delta/56/event_labels.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/event_labels_background_update.sql b/synapse/storage/databases/main/schema/delta/56/event_labels_background_update.sql
index 5f5e0499ae..5f5e0499ae 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/event_labels_background_update.sql
+++ b/synapse/storage/databases/main/schema/delta/56/event_labels_background_update.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/fix_room_keys_index.sql b/synapse/storage/databases/main/schema/delta/56/fix_room_keys_index.sql
index 014cb3b538..014cb3b538 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/fix_room_keys_index.sql
+++ b/synapse/storage/databases/main/schema/delta/56/fix_room_keys_index.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/hidden_devices.sql b/synapse/storage/databases/main/schema/delta/56/hidden_devices.sql
index 67f8b20297..67f8b20297 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/hidden_devices.sql
+++ b/synapse/storage/databases/main/schema/delta/56/hidden_devices.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/hidden_devices_fix.sql.sqlite b/synapse/storage/databases/main/schema/delta/56/hidden_devices_fix.sql.sqlite
index e8b1fd35d8..e8b1fd35d8 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/hidden_devices_fix.sql.sqlite
+++ b/synapse/storage/databases/main/schema/delta/56/hidden_devices_fix.sql.sqlite
diff --git a/synapse/storage/data_stores/main/schema/delta/56/nuke_empty_communities_from_db.sql b/synapse/storage/databases/main/schema/delta/56/nuke_empty_communities_from_db.sql
index 4f24c1405d..4f24c1405d 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/nuke_empty_communities_from_db.sql
+++ b/synapse/storage/databases/main/schema/delta/56/nuke_empty_communities_from_db.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/public_room_list_idx.sql b/synapse/storage/databases/main/schema/delta/56/public_room_list_idx.sql
index 7be31ffebb..7be31ffebb 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/public_room_list_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/56/public_room_list_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor.sql b/synapse/storage/databases/main/schema/delta/56/redaction_censor.sql
index ea95db0ed7..ea95db0ed7 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor.sql
+++ b/synapse/storage/databases/main/schema/delta/56/redaction_censor.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor2.sql b/synapse/storage/databases/main/schema/delta/56/redaction_censor2.sql
index 49ce35d794..49ce35d794 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor2.sql
+++ b/synapse/storage/databases/main/schema/delta/56/redaction_censor2.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor3_fix_update.sql.postgres b/synapse/storage/databases/main/schema/delta/56/redaction_censor3_fix_update.sql.postgres
index 67471f3ef5..67471f3ef5 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor3_fix_update.sql.postgres
+++ b/synapse/storage/databases/main/schema/delta/56/redaction_censor3_fix_update.sql.postgres
diff --git a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor4.sql b/synapse/storage/databases/main/schema/delta/56/redaction_censor4.sql
index b7550f6f4e..b7550f6f4e 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/redaction_censor4.sql
+++ b/synapse/storage/databases/main/schema/delta/56/redaction_censor4.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/remove_tombstoned_rooms_from_directory.sql b/synapse/storage/databases/main/schema/delta/56/remove_tombstoned_rooms_from_directory.sql
index aeb17813d3..aeb17813d3 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/remove_tombstoned_rooms_from_directory.sql
+++ b/synapse/storage/databases/main/schema/delta/56/remove_tombstoned_rooms_from_directory.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/room_key_etag.sql b/synapse/storage/databases/main/schema/delta/56/room_key_etag.sql
index 7d70dd071e..7d70dd071e 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/room_key_etag.sql
+++ b/synapse/storage/databases/main/schema/delta/56/room_key_etag.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/room_membership_idx.sql b/synapse/storage/databases/main/schema/delta/56/room_membership_idx.sql
index 92ab1f5e65..92ab1f5e65 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/room_membership_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/56/room_membership_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/room_retention.sql b/synapse/storage/databases/main/schema/delta/56/room_retention.sql
index ee6cdf7a14..ee6cdf7a14 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/room_retention.sql
+++ b/synapse/storage/databases/main/schema/delta/56/room_retention.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/signing_keys.sql b/synapse/storage/databases/main/schema/delta/56/signing_keys.sql
index 5c5fffcafb..5c5fffcafb 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/signing_keys.sql
+++ b/synapse/storage/databases/main/schema/delta/56/signing_keys.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/signing_keys_nonunique_signatures.sql b/synapse/storage/databases/main/schema/delta/56/signing_keys_nonunique_signatures.sql
index 0aa90ebf0c..0aa90ebf0c 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/signing_keys_nonunique_signatures.sql
+++ b/synapse/storage/databases/main/schema/delta/56/signing_keys_nonunique_signatures.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/stats_separated.sql b/synapse/storage/databases/main/schema/delta/56/stats_separated.sql
index bbdde121e8..bbdde121e8 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/stats_separated.sql
+++ b/synapse/storage/databases/main/schema/delta/56/stats_separated.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/unique_user_filter_index.py b/synapse/storage/databases/main/schema/delta/56/unique_user_filter_index.py
index 1de8b54961..1de8b54961 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/unique_user_filter_index.py
+++ b/synapse/storage/databases/main/schema/delta/56/unique_user_filter_index.py
diff --git a/synapse/storage/data_stores/main/schema/delta/56/user_external_ids.sql b/synapse/storage/databases/main/schema/delta/56/user_external_ids.sql
index 91390c4527..91390c4527 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/user_external_ids.sql
+++ b/synapse/storage/databases/main/schema/delta/56/user_external_ids.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/56/users_in_public_rooms_idx.sql b/synapse/storage/databases/main/schema/delta/56/users_in_public_rooms_idx.sql
index 149f8be8b6..149f8be8b6 100644
--- a/synapse/storage/data_stores/main/schema/delta/56/users_in_public_rooms_idx.sql
+++ b/synapse/storage/databases/main/schema/delta/56/users_in_public_rooms_idx.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/57/delete_old_current_state_events.sql b/synapse/storage/databases/main/schema/delta/57/delete_old_current_state_events.sql
index aec06c8261..aec06c8261 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/delete_old_current_state_events.sql
+++ b/synapse/storage/databases/main/schema/delta/57/delete_old_current_state_events.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/57/device_list_remote_cache_stale.sql b/synapse/storage/databases/main/schema/delta/57/device_list_remote_cache_stale.sql
index c3b6de2099..c3b6de2099 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/device_list_remote_cache_stale.sql
+++ b/synapse/storage/databases/main/schema/delta/57/device_list_remote_cache_stale.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/57/local_current_membership.py b/synapse/storage/databases/main/schema/delta/57/local_current_membership.py
index 63b5acdcf7..63b5acdcf7 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/local_current_membership.py
+++ b/synapse/storage/databases/main/schema/delta/57/local_current_membership.py
diff --git a/synapse/storage/data_stores/main/schema/delta/57/remove_sent_outbound_pokes.sql b/synapse/storage/databases/main/schema/delta/57/remove_sent_outbound_pokes.sql
index 133d80af35..133d80af35 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/remove_sent_outbound_pokes.sql
+++ b/synapse/storage/databases/main/schema/delta/57/remove_sent_outbound_pokes.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column.sql b/synapse/storage/databases/main/schema/delta/57/rooms_version_column.sql
index 352a66f5b0..352a66f5b0 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column.sql
+++ b/synapse/storage/databases/main/schema/delta/57/rooms_version_column.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.postgres b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_2.sql.postgres
index c601cff6de..c601cff6de 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.postgres
+++ b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_2.sql.postgres
diff --git a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.sqlite b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_2.sql.sqlite
index 335c6f2074..335c6f2074 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_2.sql.sqlite
+++ b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_2.sql.sqlite
diff --git a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_3.sql.postgres b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_3.sql.postgres
index 92aaadde0d..92aaadde0d 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_3.sql.postgres
+++ b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_3.sql.postgres
diff --git a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_3.sql.sqlite b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_3.sql.sqlite
index e19dab97cb..e19dab97cb 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/rooms_version_column_3.sql.sqlite
+++ b/synapse/storage/databases/main/schema/delta/57/rooms_version_column_3.sql.sqlite
diff --git a/synapse/storage/data_stores/main/schema/delta/58/02remove_dup_outbound_pokes.sql b/synapse/storage/databases/main/schema/delta/58/02remove_dup_outbound_pokes.sql
index fdc39e9ba5..fdc39e9ba5 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/02remove_dup_outbound_pokes.sql
+++ b/synapse/storage/databases/main/schema/delta/58/02remove_dup_outbound_pokes.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/58/03persist_ui_auth.sql b/synapse/storage/databases/main/schema/delta/58/03persist_ui_auth.sql
index dcb593fc2d..dcb593fc2d 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/03persist_ui_auth.sql
+++ b/synapse/storage/databases/main/schema/delta/58/03persist_ui_auth.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/58/05cache_instance.sql.postgres b/synapse/storage/databases/main/schema/delta/58/05cache_instance.sql.postgres
index aa46eb0e10..aa46eb0e10 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/05cache_instance.sql.postgres
+++ b/synapse/storage/databases/main/schema/delta/58/05cache_instance.sql.postgres
diff --git a/synapse/storage/data_stores/main/schema/delta/58/06dlols_unique_idx.py b/synapse/storage/databases/main/schema/delta/58/06dlols_unique_idx.py
index d353f2bcb3..d353f2bcb3 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/06dlols_unique_idx.py
+++ b/synapse/storage/databases/main/schema/delta/58/06dlols_unique_idx.py
diff --git a/synapse/storage/data_stores/main/schema/delta/58/08_media_safe_from_quarantine.sql.postgres b/synapse/storage/databases/main/schema/delta/58/08_media_safe_from_quarantine.sql.postgres
index 597f2ffd3d..597f2ffd3d 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/08_media_safe_from_quarantine.sql.postgres
+++ b/synapse/storage/databases/main/schema/delta/58/08_media_safe_from_quarantine.sql.postgres
diff --git a/synapse/storage/data_stores/main/schema/delta/58/08_media_safe_from_quarantine.sql.sqlite b/synapse/storage/databases/main/schema/delta/58/08_media_safe_from_quarantine.sql.sqlite
index 69db89ac0e..69db89ac0e 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/08_media_safe_from_quarantine.sql.sqlite
+++ b/synapse/storage/databases/main/schema/delta/58/08_media_safe_from_quarantine.sql.sqlite
diff --git a/synapse/storage/data_stores/main/schema/delta/58/10drop_local_rejections_stream.sql b/synapse/storage/databases/main/schema/delta/58/10drop_local_rejections_stream.sql
index eb57203e46..eb57203e46 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/10drop_local_rejections_stream.sql
+++ b/synapse/storage/databases/main/schema/delta/58/10drop_local_rejections_stream.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/58/10federation_pos_instance_name.sql b/synapse/storage/databases/main/schema/delta/58/10federation_pos_instance_name.sql
index 1cc2633aad..1cc2633aad 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/10federation_pos_instance_name.sql
+++ b/synapse/storage/databases/main/schema/delta/58/10federation_pos_instance_name.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/58/11user_id_seq.py b/synapse/storage/databases/main/schema/delta/58/11user_id_seq.py
index 2011f6bceb..4310ec12ce 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/11user_id_seq.py
+++ b/synapse/storage/databases/main/schema/delta/58/11user_id_seq.py
@@ -16,7 +16,7 @@
 Adds a postgres SEQUENCE for generating guest user IDs.
 """
 
-from synapse.storage.data_stores.main.registration import (
+from synapse.storage.databases.main.registration import (
     find_max_generated_user_id_localpart,
 )
 from synapse.storage.engines import PostgresEngine
diff --git a/synapse/storage/data_stores/main/schema/delta/58/12room_stats.sql b/synapse/storage/databases/main/schema/delta/58/12room_stats.sql
index cade5dcca8..cade5dcca8 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/12room_stats.sql
+++ b/synapse/storage/databases/main/schema/delta/58/12room_stats.sql
diff --git a/synapse/storage/data_stores/main/schema/delta/58/12unread_messages.sql b/synapse/storage/databases/main/schema/delta/58/12unread_messages.sql
index 531b532c73..531b532c73 100644
--- a/synapse/storage/data_stores/main/schema/delta/58/12unread_messages.sql
+++ b/synapse/storage/databases/main/schema/delta/58/12unread_messages.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/application_services.sql b/synapse/storage/databases/main/schema/full_schemas/16/application_services.sql
index 883fcd10b2..883fcd10b2 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/application_services.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/application_services.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/event_edges.sql b/synapse/storage/databases/main/schema/full_schemas/16/event_edges.sql
index 10ce2aa7a0..10ce2aa7a0 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/event_edges.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/event_edges.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/event_signatures.sql b/synapse/storage/databases/main/schema/full_schemas/16/event_signatures.sql
index 95826da431..95826da431 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/event_signatures.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/event_signatures.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/im.sql b/synapse/storage/databases/main/schema/full_schemas/16/im.sql
index a1a2aa8e5b..a1a2aa8e5b 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/im.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/im.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/keys.sql b/synapse/storage/databases/main/schema/full_schemas/16/keys.sql
index 11cdffdbb3..11cdffdbb3 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/keys.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/keys.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/media_repository.sql b/synapse/storage/databases/main/schema/full_schemas/16/media_repository.sql
index 8f3759bb2a..8f3759bb2a 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/media_repository.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/media_repository.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/presence.sql b/synapse/storage/databases/main/schema/full_schemas/16/presence.sql
index 01d2d8f833..01d2d8f833 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/presence.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/presence.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/profiles.sql b/synapse/storage/databases/main/schema/full_schemas/16/profiles.sql
index c04f4747d9..c04f4747d9 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/profiles.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/profiles.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/push.sql b/synapse/storage/databases/main/schema/full_schemas/16/push.sql
index e44465cf45..e44465cf45 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/push.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/push.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/redactions.sql b/synapse/storage/databases/main/schema/full_schemas/16/redactions.sql
index 318f0d9aa5..318f0d9aa5 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/redactions.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/redactions.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/room_aliases.sql b/synapse/storage/databases/main/schema/full_schemas/16/room_aliases.sql
index d47da3b12f..d47da3b12f 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/room_aliases.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/room_aliases.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/state.sql b/synapse/storage/databases/main/schema/full_schemas/16/state.sql
index 96391a8f0e..96391a8f0e 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/state.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/state.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/transactions.sql b/synapse/storage/databases/main/schema/full_schemas/16/transactions.sql
index 17e67bedac..17e67bedac 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/transactions.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/transactions.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/16/users.sql b/synapse/storage/databases/main/schema/full_schemas/16/users.sql
index f013aa8b18..f013aa8b18 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/16/users.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/16/users.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/54/full.sql.postgres b/synapse/storage/databases/main/schema/full_schemas/54/full.sql.postgres
index 889a9a0ce4..889a9a0ce4 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/54/full.sql.postgres
+++ b/synapse/storage/databases/main/schema/full_schemas/54/full.sql.postgres
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/54/full.sql.sqlite b/synapse/storage/databases/main/schema/full_schemas/54/full.sql.sqlite
index a0411ede7e..a0411ede7e 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/54/full.sql.sqlite
+++ b/synapse/storage/databases/main/schema/full_schemas/54/full.sql.sqlite
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/54/stream_positions.sql b/synapse/storage/databases/main/schema/full_schemas/54/stream_positions.sql
index 91d21b2921..91d21b2921 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/54/stream_positions.sql
+++ b/synapse/storage/databases/main/schema/full_schemas/54/stream_positions.sql
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/README.md b/synapse/storage/databases/main/schema/full_schemas/README.md
index c00f287190..c00f287190 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/README.md
+++ b/synapse/storage/databases/main/schema/full_schemas/README.md
diff --git a/synapse/storage/data_stores/main/search.py b/synapse/storage/databases/main/search.py
index d52228297c..2162d0712d 100644
--- a/synapse/storage/data_stores/main/search.py
+++ b/synapse/storage/databases/main/search.py
@@ -21,8 +21,8 @@ from twisted.internet import defer
 
 from synapse.api.errors import SynapseError
 from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause
-from synapse.storage.data_stores.main.events_worker import EventRedactBehaviour
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.events_worker import EventRedactBehaviour
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 
 logger = logging.getLogger(__name__)
@@ -88,16 +88,16 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
     EVENT_SEARCH_USE_GIST_POSTGRES_NAME = "event_search_postgres_gist"
     EVENT_SEARCH_USE_GIN_POSTGRES_NAME = "event_search_postgres_gin"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SearchBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
         if not hs.config.enable_search:
             return
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.EVENT_SEARCH_UPDATE_NAME, self._background_reindex_search
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.EVENT_SEARCH_ORDER_UPDATE_NAME, self._background_reindex_search_order
         )
 
@@ -106,11 +106,11 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
         # a GIN index. However, it's possible that some people might still have
         # the background update queued, so we register a handler to clear the
         # background update.
-        self.db.updates.register_noop_background_update(
+        self.db_pool.updates.register_noop_background_update(
             self.EVENT_SEARCH_USE_GIST_POSTGRES_NAME
         )
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.EVENT_SEARCH_USE_GIN_POSTGRES_NAME, self._background_reindex_gin_search
         )
 
@@ -140,7 +140,7 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
             # store_search_entries_txn with a generator function, but that
             # would mean having two cursors open on the database at once.
             # Instead we just build a list of results.
-            rows = self.db.cursor_to_dict(txn)
+            rows = self.db_pool.cursor_to_dict(txn)
             if not rows:
                 return 0
 
@@ -200,18 +200,20 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
                 "rows_inserted": rows_inserted + len(event_search_rows),
             }
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, self.EVENT_SEARCH_UPDATE_NAME, progress
             )
 
             return len(event_search_rows)
 
-        result = yield self.db.runInteraction(
+        result = yield self.db_pool.runInteraction(
             self.EVENT_SEARCH_UPDATE_NAME, reindex_search_txn
         )
 
         if not result:
-            yield self.db.updates._end_background_update(self.EVENT_SEARCH_UPDATE_NAME)
+            yield self.db_pool.updates._end_background_update(
+                self.EVENT_SEARCH_UPDATE_NAME
+            )
 
         return result
 
@@ -253,9 +255,9 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
                 conn.set_session(autocommit=False)
 
         if isinstance(self.database_engine, PostgresEngine):
-            yield self.db.runWithConnection(create_index)
+            yield self.db_pool.runWithConnection(create_index)
 
-        yield self.db.updates._end_background_update(
+        yield self.db_pool.updates._end_background_update(
             self.EVENT_SEARCH_USE_GIN_POSTGRES_NAME
         )
         return 1
@@ -286,14 +288,14 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
                 )
                 conn.set_session(autocommit=False)
 
-            yield self.db.runWithConnection(create_index)
+            yield self.db_pool.runWithConnection(create_index)
 
             pg = dict(progress)
             pg["have_added_indexes"] = True
 
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 self.EVENT_SEARCH_ORDER_UPDATE_NAME,
-                self.db.updates._background_update_progress_txn,
+                self.db_pool.updates._background_update_progress_txn,
                 self.EVENT_SEARCH_ORDER_UPDATE_NAME,
                 pg,
             )
@@ -323,18 +325,18 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
                 "have_added_indexes": True,
             }
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, self.EVENT_SEARCH_ORDER_UPDATE_NAME, progress
             )
 
             return len(rows), True
 
-        num_rows, finished = yield self.db.runInteraction(
+        num_rows, finished = yield self.db_pool.runInteraction(
             self.EVENT_SEARCH_ORDER_UPDATE_NAME, reindex_search_txn
         )
 
         if not finished:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 self.EVENT_SEARCH_ORDER_UPDATE_NAME
             )
 
@@ -342,7 +344,7 @@ class SearchBackgroundUpdateStore(SearchWorkerStore):
 
 
 class SearchStore(SearchBackgroundUpdateStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(SearchStore, self).__init__(database, db_conn, hs)
 
     @defer.inlineCallbacks
@@ -423,8 +425,8 @@ class SearchStore(SearchBackgroundUpdateStore):
         # entire table from the database.
         sql += " ORDER BY rank DESC LIMIT 500"
 
-        results = yield self.db.execute(
-            "search_msgs", self.db.cursor_to_dict, sql, *args
+        results = yield self.db_pool.execute(
+            "search_msgs", self.db_pool.cursor_to_dict, sql, *args
         )
 
         results = list(filter(lambda row: row["room_id"] in room_ids, results))
@@ -444,8 +446,8 @@ class SearchStore(SearchBackgroundUpdateStore):
 
         count_sql += " GROUP BY room_id"
 
-        count_results = yield self.db.execute(
-            "search_rooms_count", self.db.cursor_to_dict, count_sql, *count_args
+        count_results = yield self.db_pool.execute(
+            "search_rooms_count", self.db_pool.cursor_to_dict, count_sql, *count_args
         )
 
         count = sum(row["count"] for row in count_results if row["room_id"] in room_ids)
@@ -575,8 +577,8 @@ class SearchStore(SearchBackgroundUpdateStore):
 
         args.append(limit)
 
-        results = yield self.db.execute(
-            "search_rooms", self.db.cursor_to_dict, sql, *args
+        results = yield self.db_pool.execute(
+            "search_rooms", self.db_pool.cursor_to_dict, sql, *args
         )
 
         results = list(filter(lambda row: row["room_id"] in room_ids, results))
@@ -596,8 +598,8 @@ class SearchStore(SearchBackgroundUpdateStore):
 
         count_sql += " GROUP BY room_id"
 
-        count_results = yield self.db.execute(
-            "search_rooms_count", self.db.cursor_to_dict, count_sql, *count_args
+        count_results = yield self.db_pool.execute(
+            "search_rooms_count", self.db_pool.cursor_to_dict, count_sql, *count_args
         )
 
         count = sum(row["count"] for row in count_results if row["room_id"] in room_ids)
@@ -682,7 +684,7 @@ class SearchStore(SearchBackgroundUpdateStore):
 
             return highlight_words
 
-        return self.db.runInteraction("_find_highlights", f)
+        return self.db_pool.runInteraction("_find_highlights", f)
 
 
 def _to_postgres_options(options_dict):
diff --git a/synapse/storage/data_stores/main/signatures.py b/synapse/storage/databases/main/signatures.py
index 36244d9f5d..dae8e8bd29 100644
--- a/synapse/storage/data_stores/main/signatures.py
+++ b/synapse/storage/databases/main/signatures.py
@@ -38,7 +38,7 @@ class SignatureWorkerStore(SQLBaseStore):
                 for event_id in event_ids
             }
 
-        return self.db.runInteraction("get_event_reference_hashes", f)
+        return self.db_pool.runInteraction("get_event_reference_hashes", f)
 
     @defer.inlineCallbacks
     def add_event_hashes(self, event_ids):
diff --git a/synapse/storage/data_stores/main/state.py b/synapse/storage/databases/main/state.py
index a360699408..96e0378e50 100644
--- a/synapse/storage/data_stores/main/state.py
+++ b/synapse/storage/databases/main/state.py
@@ -23,9 +23,9 @@ from synapse.api.errors import NotFoundError, UnsupportedRoomVersionError
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion
 from synapse.events import EventBase
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.data_stores.main.roommember import RoomMemberWorkerStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
+from synapse.storage.databases.main.roommember import RoomMemberWorkerStore
 from synapse.storage.state import StateFilter
 from synapse.util.caches import intern_string
 from synapse.util.caches.descriptors import cached, cachedList
@@ -54,7 +54,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
     """The parts of StateGroupStore that can be called from workers.
     """
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(StateGroupWorkerStore, self).__init__(database, db_conn, hs)
 
     async def get_room_version(self, room_id: str) -> RoomVersion:
@@ -93,7 +93,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         # We really should have an entry in the rooms table for every room we
         # care about, but let's be a bit paranoid (at least while the background
         # update is happening) to avoid breaking existing rooms.
-        version = await self.db.simple_select_one_onecol(
+        version = await self.db_pool.simple_select_one_onecol(
             table="rooms",
             keyvalues={"room_id": room_id},
             retcol="room_version",
@@ -184,7 +184,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
             return {(intern_string(r[0]), intern_string(r[1])): r[2] for r in txn}
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_current_state_ids", _get_current_state_ids_txn
         )
 
@@ -231,7 +231,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
             return results
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_filtered_current_state_ids", _get_filtered_current_state_ids_txn
         )
 
@@ -261,7 +261,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
     @cached(max_entries=50000)
     def _get_state_group_for_event(self, event_id):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="event_to_state_groups",
             keyvalues={"event_id": event_id},
             retcol="state_group",
@@ -278,7 +278,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
     def _get_state_group_for_events(self, event_ids):
         """Returns mapping event_id -> state_group
         """
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="event_to_state_groups",
             column="event_id",
             iterable=event_ids,
@@ -301,7 +301,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             The subset of state groups that are referenced.
         """
 
-        rows = await self.db.simple_select_many_batch(
+        rows = await self.db_pool.simple_select_many_batch(
             table="event_to_state_groups",
             column="state_group",
             iterable=state_groups,
@@ -319,25 +319,25 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
     EVENT_STATE_GROUP_INDEX_UPDATE_NAME = "event_to_state_groups_sg_index"
     DELETE_CURRENT_STATE_UPDATE_NAME = "delete_old_current_state_events"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(MainStateBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
         self.server_name = hs.hostname
 
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             self.CURRENT_STATE_INDEX_UPDATE_NAME,
             index_name="current_state_events_member_index",
             table="current_state_events",
             columns=["state_key"],
             where_clause="type='m.room.member'",
         )
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             self.EVENT_STATE_GROUP_INDEX_UPDATE_NAME,
             index_name="event_to_state_groups_sg_index",
             table="event_to_state_groups",
             columns=["state_group"],
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.DELETE_CURRENT_STATE_UPDATE_NAME, self._background_remove_left_rooms,
         )
 
@@ -429,7 +429,7 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
             # potentially stale, since there may have been a period where the
             # server didn't share a room with the remote user and therefore may
             # have missed any device updates.
-            rows = self.db.simple_select_many_txn(
+            rows = self.db_pool.simple_select_many_txn(
                 txn,
                 table="current_state_events",
                 column="room_id",
@@ -441,7 +441,7 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
             potentially_left_users = {row["state_key"] for row in rows}
 
             # Now lets actually delete the rooms from the DB.
-            self.db.simple_delete_many_txn(
+            self.db_pool.simple_delete_many_txn(
                 txn,
                 table="current_state_events",
                 column="room_id",
@@ -449,7 +449,7 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
                 keyvalues={},
             )
 
-            self.db.simple_delete_many_txn(
+            self.db_pool.simple_delete_many_txn(
                 txn,
                 table="event_forward_extremities",
                 column="room_id",
@@ -457,7 +457,7 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
                 keyvalues={},
             )
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn,
                 self.DELETE_CURRENT_STATE_UPDATE_NAME,
                 {"last_room_id": room_ids[-1]},
@@ -465,12 +465,12 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
 
             return False, potentially_left_users
 
-        finished, potentially_left_users = await self.db.runInteraction(
+        finished, potentially_left_users = await self.db_pool.runInteraction(
             "_background_remove_left_rooms", _background_remove_left_rooms_txn
         )
 
         if finished:
-            await self.db.updates._end_background_update(
+            await self.db_pool.updates._end_background_update(
                 self.DELETE_CURRENT_STATE_UPDATE_NAME
             )
 
@@ -505,5 +505,5 @@ class StateStore(StateGroupWorkerStore, MainStateBackgroundUpdateStore):
       * `state_groups_state`: Maps state group to state events.
     """
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(StateStore, self).__init__(database, db_conn, hs)
diff --git a/synapse/storage/data_stores/main/state_deltas.py b/synapse/storage/databases/main/state_deltas.py
index 725e12507f..0d963c98ff 100644
--- a/synapse/storage/data_stores/main/state_deltas.py
+++ b/synapse/storage/databases/main/state_deltas.py
@@ -100,14 +100,14 @@ class StateDeltasStore(SQLBaseStore):
                 ORDER BY stream_id ASC
             """
             txn.execute(sql, (prev_stream_id, clipped_stream_id))
-            return clipped_stream_id, self.db.cursor_to_dict(txn)
+            return clipped_stream_id, self.db_pool.cursor_to_dict(txn)
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_current_state_deltas", get_current_state_deltas_txn
         )
 
     def _get_max_stream_id_in_current_state_deltas_txn(self, txn):
-        return self.db.simple_select_one_onecol_txn(
+        return self.db_pool.simple_select_one_onecol_txn(
             txn,
             table="current_state_delta_stream",
             keyvalues={},
@@ -115,7 +115,7 @@ class StateDeltasStore(SQLBaseStore):
         )
 
     def get_max_stream_id_in_current_state_deltas(self):
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_max_stream_id_in_current_state_deltas",
             self._get_max_stream_id_in_current_state_deltas_txn,
         )
diff --git a/synapse/storage/data_stores/main/stats.py b/synapse/storage/databases/main/stats.py
index 40db8f594e..802c9019b9 100644
--- a/synapse/storage/data_stores/main/stats.py
+++ b/synapse/storage/databases/main/stats.py
@@ -21,8 +21,8 @@ from typing import Tuple
 from twisted.internet.defer import DeferredLock
 
 from synapse.api.constants import EventTypes, Membership
-from synapse.storage.data_stores.main.state_deltas import StateDeltasStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.state_deltas import StateDeltasStore
 from synapse.storage.engines import PostgresEngine
 from synapse.util.caches.descriptors import cached
 
@@ -59,7 +59,7 @@ TYPE_TO_ORIGIN_TABLE = {"room": ("rooms", "room_id"), "user": ("users", "name")}
 
 
 class StatsStore(StateDeltasStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(StatsStore, self).__init__(database, db_conn, hs)
 
         self.server_name = hs.hostname
@@ -69,20 +69,20 @@ class StatsStore(StateDeltasStore):
 
         self.stats_delta_processing_lock = DeferredLock()
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "populate_stats_process_rooms", self._populate_stats_process_rooms
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "populate_stats_process_rooms_2", self._populate_stats_process_rooms_2
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "populate_stats_process_users", self._populate_stats_process_users
         )
         # we no longer need to perform clean-up, but we will give ourselves
         # the potential to reintroduce it in the future – so documentation
         # will still encourage the use of this no-op handler.
-        self.db.updates.register_noop_background_update("populate_stats_cleanup")
-        self.db.updates.register_noop_background_update("populate_stats_prepare")
+        self.db_pool.updates.register_noop_background_update("populate_stats_cleanup")
+        self.db_pool.updates.register_noop_background_update("populate_stats_prepare")
 
     def quantise_stats_time(self, ts):
         """
@@ -105,7 +105,9 @@ class StatsStore(StateDeltasStore):
         This is a background update which regenerates statistics for users.
         """
         if not self.stats_enabled:
-            await self.db.updates._end_background_update("populate_stats_process_users")
+            await self.db_pool.updates._end_background_update(
+                "populate_stats_process_users"
+            )
             return 1
 
         last_user_id = progress.get("last_user_id", "")
@@ -120,22 +122,24 @@ class StatsStore(StateDeltasStore):
             txn.execute(sql, (last_user_id, batch_size))
             return [r for r, in txn]
 
-        users_to_work_on = await self.db.runInteraction(
+        users_to_work_on = await self.db_pool.runInteraction(
             "_populate_stats_process_users", _get_next_batch
         )
 
         # No more rooms -- complete the transaction.
         if not users_to_work_on:
-            await self.db.updates._end_background_update("populate_stats_process_users")
+            await self.db_pool.updates._end_background_update(
+                "populate_stats_process_users"
+            )
             return 1
 
         for user_id in users_to_work_on:
             await self._calculate_and_set_initial_state_for_user(user_id)
             progress["last_user_id"] = user_id
 
-        await self.db.runInteraction(
+        await self.db_pool.runInteraction(
             "populate_stats_process_users",
-            self.db.updates._background_update_progress_txn,
+            self.db_pool.updates._background_update_progress_txn,
             "populate_stats_process_users",
             progress,
         )
@@ -153,7 +157,9 @@ class StatsStore(StateDeltasStore):
 
         Further context: https://github.com/matrix-org/synapse/pull/7977
         """
-        await self.db.updates._end_background_update("populate_stats_process_rooms")
+        await self.db_pool.updates._end_background_update(
+            "populate_stats_process_rooms"
+        )
         return 1
 
     async def _populate_stats_process_rooms_2(self, progress, batch_size):
@@ -164,7 +170,7 @@ class StatsStore(StateDeltasStore):
         reasoning.
         """
         if not self.stats_enabled:
-            await self.db.updates._end_background_update(
+            await self.db_pool.updates._end_background_update(
                 "populate_stats_process_rooms_2"
             )
             return 1
@@ -181,13 +187,13 @@ class StatsStore(StateDeltasStore):
             txn.execute(sql, (last_room_id, batch_size))
             return [r for r, in txn]
 
-        rooms_to_work_on = await self.db.runInteraction(
+        rooms_to_work_on = await self.db_pool.runInteraction(
             "populate_stats_rooms_2_get_batch", _get_next_batch
         )
 
         # No more rooms -- complete the transaction.
         if not rooms_to_work_on:
-            await self.db.updates._end_background_update(
+            await self.db_pool.updates._end_background_update(
                 "populate_stats_process_rooms_2"
             )
             return 1
@@ -196,9 +202,9 @@ class StatsStore(StateDeltasStore):
             await self._calculate_and_set_initial_state_for_room(room_id)
             progress["last_room_id"] = room_id
 
-        await self.db.runInteraction(
+        await self.db_pool.runInteraction(
             "_populate_stats_process_rooms_2",
-            self.db.updates._background_update_progress_txn,
+            self.db_pool.updates._background_update_progress_txn,
             "populate_stats_process_rooms_2",
             progress,
         )
@@ -209,7 +215,7 @@ class StatsStore(StateDeltasStore):
         """
         Returns the stats processor positions.
         """
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="stats_incremental_position",
             keyvalues={},
             retcol="stream_id",
@@ -238,7 +244,7 @@ class StatsStore(StateDeltasStore):
             if field and "\0" in field:
                 fields[col] = None
 
-        return self.db.simple_upsert(
+        return self.db_pool.simple_upsert(
             table="room_stats_state",
             keyvalues={"room_id": room_id},
             values=fields,
@@ -259,7 +265,7 @@ class StatsStore(StateDeltasStore):
             Deferred[list[dict]], where the dict has the keys of
             ABSOLUTE_STATS_FIELDS[stats_type],  and "bucket_size" and "end_ts".
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_statistics_for_subject",
             self._get_statistics_for_subject_txn,
             stats_type,
@@ -280,7 +286,7 @@ class StatsStore(StateDeltasStore):
             ABSOLUTE_STATS_FIELDS[stats_type] + PER_SLICE_FIELDS[stats_type]
         )
 
-        slice_list = self.db.simple_select_list_paginate_txn(
+        slice_list = self.db_pool.simple_select_list_paginate_txn(
             txn,
             table + "_historical",
             "end_ts",
@@ -306,7 +312,7 @@ class StatsStore(StateDeltasStore):
         """
         table, id_col = TYPE_TO_TABLE[stats_type]
 
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             "%s_current" % (table,),
             keyvalues={id_col: id},
             retcol="completed_delta_stream_id",
@@ -342,14 +348,14 @@ class StatsStore(StateDeltasStore):
                         complete_with_stream_id=stream_id,
                     )
 
-            self.db.simple_update_one_txn(
+            self.db_pool.simple_update_one_txn(
                 txn,
                 table="stats_incremental_position",
                 keyvalues={},
                 updatevalues={"stream_id": stream_id},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "bulk_update_stats_delta", _bulk_update_stats_delta_txn
         )
 
@@ -380,7 +386,7 @@ class StatsStore(StateDeltasStore):
                 Does not work with per-slice fields.
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "update_stats_delta",
             self._update_stats_delta_txn,
             ts,
@@ -515,17 +521,17 @@ class StatsStore(StateDeltasStore):
         else:
             self.database_engine.lock_table(txn, table)
             retcols = list(chain(absolutes.keys(), additive_relatives.keys()))
-            current_row = self.db.simple_select_one_txn(
+            current_row = self.db_pool.simple_select_one_txn(
                 txn, table, keyvalues, retcols, allow_none=True
             )
             if current_row is None:
                 merged_dict = {**keyvalues, **absolutes, **additive_relatives}
-                self.db.simple_insert_txn(txn, table, merged_dict)
+                self.db_pool.simple_insert_txn(txn, table, merged_dict)
             else:
                 for (key, val) in additive_relatives.items():
                     current_row[key] += val
                 current_row.update(absolutes)
-                self.db.simple_update_one_txn(txn, table, keyvalues, current_row)
+                self.db_pool.simple_update_one_txn(txn, table, keyvalues, current_row)
 
     def _upsert_copy_from_table_with_additive_relatives_txn(
         self,
@@ -612,11 +618,11 @@ class StatsStore(StateDeltasStore):
             txn.execute(sql, qargs)
         else:
             self.database_engine.lock_table(txn, into_table)
-            src_row = self.db.simple_select_one_txn(
+            src_row = self.db_pool.simple_select_one_txn(
                 txn, src_table, keyvalues, copy_columns
             )
             all_dest_keyvalues = {**keyvalues, **extra_dst_keyvalues}
-            dest_current_row = self.db.simple_select_one_txn(
+            dest_current_row = self.db_pool.simple_select_one_txn(
                 txn,
                 into_table,
                 keyvalues=all_dest_keyvalues,
@@ -632,11 +638,13 @@ class StatsStore(StateDeltasStore):
                     **src_row,
                     **additive_relatives,
                 }
-                self.db.simple_insert_txn(txn, into_table, merged_dict)
+                self.db_pool.simple_insert_txn(txn, into_table, merged_dict)
             else:
                 for (key, val) in additive_relatives.items():
                     src_row[key] = dest_current_row[key] + val
-                self.db.simple_update_txn(txn, into_table, all_dest_keyvalues, src_row)
+                self.db_pool.simple_update_txn(
+                    txn, into_table, all_dest_keyvalues, src_row
+                )
 
     def get_changes_room_total_events_and_bytes(self, min_pos, max_pos):
         """Fetches the counts of events in the given range of stream IDs.
@@ -650,7 +658,7 @@ class StatsStore(StateDeltasStore):
             changes.
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "stats_incremental_total_events_and_bytes",
             self.get_changes_room_total_events_and_bytes_txn,
             min_pos,
@@ -733,7 +741,7 @@ class StatsStore(StateDeltasStore):
         def _fetch_current_state_stats(txn):
             pos = self.get_room_max_stream_ordering()
 
-            rows = self.db.simple_select_many_txn(
+            rows = self.db_pool.simple_select_many_txn(
                 txn,
                 table="current_state_events",
                 column="type",
@@ -789,7 +797,7 @@ class StatsStore(StateDeltasStore):
             current_state_events_count,
             users_in_room,
             pos,
-        ) = await self.db.runInteraction(
+        ) = await self.db_pool.runInteraction(
             "get_initial_state_for_room", _fetch_current_state_stats
         )
 
@@ -863,7 +871,7 @@ class StatsStore(StateDeltasStore):
             (count,) = txn.fetchone()
             return count, pos
 
-        joined_rooms, pos = await self.db.runInteraction(
+        joined_rooms, pos = await self.db_pool.runInteraction(
             "calculate_and_set_initial_state_for_user",
             _calculate_and_set_initial_state_for_user_txn,
         )
diff --git a/synapse/storage/data_stores/main/stream.py b/synapse/storage/databases/main/stream.py
index f1334a6efc..aaf225894e 100644
--- a/synapse/storage/data_stores/main/stream.py
+++ b/synapse/storage/databases/main/stream.py
@@ -45,8 +45,8 @@ from twisted.internet import defer
 
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
-from synapse.storage.database import Database, make_in_list_sql_clause
+from synapse.storage.database import DatabasePool, make_in_list_sql_clause
+from synapse.storage.databases.main.events_worker import EventsWorkerStore
 from synapse.storage.engines import PostgresEngine
 from synapse.types import RoomStreamToken
 from synapse.util.caches.stream_change_cache import StreamChangeCache
@@ -251,7 +251,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
     __metaclass__ = abc.ABCMeta
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(StreamWorkerStore, self).__init__(database, db_conn, hs)
 
         self._instance_name = hs.get_instance_name()
@@ -265,7 +265,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         self._need_to_reset_federation_stream_positions = self._send_federation
 
         events_max = self.get_room_max_stream_ordering()
-        event_cache_prefill, min_event_val = self.db.get_cache_dict(
+        event_cache_prefill, min_event_val = self.db_pool.get_cache_dict(
             db_conn,
             "events",
             entity_column="room_id",
@@ -410,7 +410,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             rows = [_EventDictReturn(row[0], None, row[1]) for row in txn]
             return rows
 
-        rows = yield self.db.runInteraction("get_room_events_stream_for_room", f)
+        rows = yield self.db_pool.runInteraction("get_room_events_stream_for_room", f)
 
         ret = yield self.get_events_as_list(
             [r.event_id for r in rows], get_prev_content=True
@@ -460,7 +460,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
             return rows
 
-        rows = yield self.db.runInteraction("get_membership_changes_for_user", f)
+        rows = yield self.db_pool.runInteraction("get_membership_changes_for_user", f)
 
         ret = yield self.get_events_as_list(
             [r.event_id for r in rows], get_prev_content=True
@@ -519,7 +519,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         end_token = RoomStreamToken.parse(end_token)
 
-        rows, token = yield self.db.runInteraction(
+        rows, token = yield self.db_pool.runInteraction(
             "get_recent_event_ids_for_room",
             self._paginate_room_events_txn,
             room_id,
@@ -556,7 +556,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             txn.execute(sql, (room_id, stream_ordering))
             return txn.fetchone()
 
-        return self.db.runInteraction("get_room_event_before_stream_ordering", _f)
+        return self.db_pool.runInteraction("get_room_event_before_stream_ordering", _f)
 
     async def get_room_events_max_id(self, room_id: Optional[str] = None) -> str:
         """Returns the current token for rooms stream.
@@ -569,7 +569,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         if room_id is None:
             return "s%d" % (token,)
         else:
-            topo = await self.db.runInteraction(
+            topo = await self.db_pool.runInteraction(
                 "_get_max_topological_txn", self._get_max_topological_txn, room_id
             )
             return "t%d-%d" % (topo, token)
@@ -583,7 +583,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         Returns:
             A deferred "s%d" stream token.
         """
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="events", keyvalues={"event_id": event_id}, retcol="stream_ordering"
         ).addCallback(lambda row: "s%d" % (row,))
 
@@ -596,7 +596,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         Returns:
             A deferred "t%d-%d" topological token.
         """
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             table="events",
             keyvalues={"event_id": event_id},
             retcols=("stream_ordering", "topological_ordering"),
@@ -620,7 +620,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             "SELECT coalesce(max(topological_ordering), 0) FROM events"
             " WHERE room_id = ? AND stream_ordering < ?"
         )
-        return self.db.execute(
+        return self.db_pool.execute(
             "get_max_topological_token", None, sql, room_id, stream_key
         ).addCallback(lambda r: r[0][0] if r else 0)
 
@@ -674,7 +674,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             dict
         """
 
-        results = yield self.db.runInteraction(
+        results = yield self.db_pool.runInteraction(
             "get_events_around",
             self._get_events_around_txn,
             room_id,
@@ -716,7 +716,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             dict
         """
 
-        results = self.db.simple_select_one_txn(
+        results = self.db_pool.simple_select_one_txn(
             txn,
             "events",
             keyvalues={"event_id": event_id, "room_id": room_id},
@@ -795,7 +795,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
             return upper_bound, [row[1] for row in rows]
 
-        upper_bound, event_ids = yield self.db.runInteraction(
+        upper_bound, event_ids = yield self.db_pool.runInteraction(
             "get_all_new_events_stream", get_all_new_events_stream_txn
         )
 
@@ -805,12 +805,12 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
     async def get_federation_out_pos(self, typ: str) -> int:
         if self._need_to_reset_federation_stream_positions:
-            await self.db.runInteraction(
+            await self.db_pool.runInteraction(
                 "_reset_federation_positions_txn", self._reset_federation_positions_txn
             )
             self._need_to_reset_federation_stream_positions = False
 
-        return await self.db.simple_select_one_onecol(
+        return await self.db_pool.simple_select_one_onecol(
             table="federation_stream_position",
             retcol="stream_id",
             keyvalues={"type": typ, "instance_name": self._instance_name},
@@ -819,12 +819,12 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
 
     async def update_federation_out_pos(self, typ, stream_id):
         if self._need_to_reset_federation_stream_positions:
-            await self.db.runInteraction(
+            await self.db_pool.runInteraction(
                 "_reset_federation_positions_txn", self._reset_federation_positions_txn
             )
             self._need_to_reset_federation_stream_positions = False
 
-        return await self.db.simple_update_one(
+        return await self.db_pool.simple_update_one(
             table="federation_stream_position",
             keyvalues={"type": typ, "instance_name": self._instance_name},
             updatevalues={"stream_id": stream_id},
@@ -854,7 +854,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         elif self._instance_name not in configured_instances:
             return
 
-        instances_in_table = self.db.simple_select_onecol_txn(
+        instances_in_table = self.db_pool.simple_select_onecol_txn(
             txn,
             table="federation_stream_position",
             keyvalues={},
@@ -885,7 +885,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         txn.execute(sql % (clause,), args)
 
         for typ, stream_id in min_positions.items():
-            self.db.simple_upsert_txn(
+            self.db_pool.simple_upsert_txn(
                 txn,
                 table="federation_stream_position",
                 keyvalues={"type": typ, "instance_name": self._instance_name},
@@ -1036,7 +1036,7 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         if to_key:
             to_key = RoomStreamToken.parse(to_key)
 
-        rows, token = yield self.db.runInteraction(
+        rows, token = yield self.db_pool.runInteraction(
             "paginate_room_events",
             self._paginate_room_events_txn,
             room_id,
diff --git a/synapse/storage/data_stores/main/tags.py b/synapse/storage/databases/main/tags.py
index bd7227773a..eedd2d96c3 100644
--- a/synapse/storage/data_stores/main/tags.py
+++ b/synapse/storage/databases/main/tags.py
@@ -22,7 +22,7 @@ from canonicaljson import json
 from twisted.internet import defer
 
 from synapse.storage._base import db_to_json
-from synapse.storage.data_stores.main.account_data import AccountDataWorkerStore
+from synapse.storage.databases.main.account_data import AccountDataWorkerStore
 from synapse.util.caches.descriptors import cached
 
 logger = logging.getLogger(__name__)
@@ -41,7 +41,7 @@ class TagsWorkerStore(AccountDataWorkerStore):
             tag strings to tag content.
         """
 
-        deferred = self.db.simple_select_list(
+        deferred = self.db_pool.simple_select_list(
             "room_tags", {"user_id": user_id}, ["room_id", "tag", "content"]
         )
 
@@ -92,7 +92,7 @@ class TagsWorkerStore(AccountDataWorkerStore):
             txn.execute(sql, (last_id, current_id, limit))
             return txn.fetchall()
 
-        tag_ids = await self.db.runInteraction(
+        tag_ids = await self.db_pool.runInteraction(
             "get_all_updated_tags", get_all_updated_tags_txn
         )
 
@@ -112,7 +112,7 @@ class TagsWorkerStore(AccountDataWorkerStore):
         batch_size = 50
         results = []
         for i in range(0, len(tag_ids), batch_size):
-            tags = await self.db.runInteraction(
+            tags = await self.db_pool.runInteraction(
                 "get_all_updated_tag_content",
                 get_tag_content,
                 tag_ids[i : i + batch_size],
@@ -155,7 +155,7 @@ class TagsWorkerStore(AccountDataWorkerStore):
         if not changed:
             return {}
 
-        room_ids = yield self.db.runInteraction(
+        room_ids = yield self.db_pool.runInteraction(
             "get_updated_tags", get_updated_tags_txn
         )
 
@@ -175,7 +175,7 @@ class TagsWorkerStore(AccountDataWorkerStore):
         Returns:
             A deferred list of string tags.
         """
-        return self.db.simple_select_list(
+        return self.db_pool.simple_select_list(
             table="room_tags",
             keyvalues={"user_id": user_id, "room_id": room_id},
             retcols=("tag", "content"),
@@ -200,7 +200,7 @@ class TagsStore(TagsWorkerStore):
         content_json = json.dumps(content)
 
         def add_tag_txn(txn, next_id):
-            self.db.simple_upsert_txn(
+            self.db_pool.simple_upsert_txn(
                 txn,
                 table="room_tags",
                 keyvalues={"user_id": user_id, "room_id": room_id, "tag": tag},
@@ -209,7 +209,7 @@ class TagsStore(TagsWorkerStore):
             self._update_revision_txn(txn, user_id, room_id, next_id)
 
         with self._account_data_id_gen.get_next() as next_id:
-            yield self.db.runInteraction("add_tag", add_tag_txn, next_id)
+            yield self.db_pool.runInteraction("add_tag", add_tag_txn, next_id)
 
         self.get_tags_for_user.invalidate((user_id,))
 
@@ -232,7 +232,7 @@ class TagsStore(TagsWorkerStore):
             self._update_revision_txn(txn, user_id, room_id, next_id)
 
         with self._account_data_id_gen.get_next() as next_id:
-            yield self.db.runInteraction("remove_tag", remove_tag_txn, next_id)
+            yield self.db_pool.runInteraction("remove_tag", remove_tag_txn, next_id)
 
         self.get_tags_for_user.invalidate((user_id,))
 
diff --git a/synapse/storage/data_stores/main/transactions.py b/synapse/storage/databases/main/transactions.py
index a9bf457939..8804c0e4ac 100644
--- a/synapse/storage/data_stores/main/transactions.py
+++ b/synapse/storage/databases/main/transactions.py
@@ -22,7 +22,7 @@ from twisted.internet import defer
 
 from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage._base import SQLBaseStore, db_to_json
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.util.caches.expiringcache import ExpiringCache
 
 db_binary_type = memoryview
@@ -46,7 +46,7 @@ class TransactionStore(SQLBaseStore):
     """A collection of queries for handling PDUs.
     """
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(TransactionStore, self).__init__(database, db_conn, hs)
 
         self._clock.looping_call(self._start_cleanup_transactions, 30 * 60 * 1000)
@@ -71,7 +71,7 @@ class TransactionStore(SQLBaseStore):
             this transaction or a 2-tuple of (int, dict)
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_received_txn_response",
             self._get_received_txn_response,
             transaction_id,
@@ -79,7 +79,7 @@ class TransactionStore(SQLBaseStore):
         )
 
     def _get_received_txn_response(self, txn, transaction_id, origin):
-        result = self.db.simple_select_one_txn(
+        result = self.db_pool.simple_select_one_txn(
             txn,
             table="received_transactions",
             keyvalues={"transaction_id": transaction_id, "origin": origin},
@@ -113,7 +113,7 @@ class TransactionStore(SQLBaseStore):
             response_json (str)
         """
 
-        return self.db.simple_insert(
+        return self.db_pool.simple_insert(
             table="received_transactions",
             values={
                 "transaction_id": transaction_id,
@@ -142,7 +142,7 @@ class TransactionStore(SQLBaseStore):
         if result is not SENTINEL:
             return result
 
-        result = yield self.db.runInteraction(
+        result = yield self.db_pool.runInteraction(
             "get_destination_retry_timings",
             self._get_destination_retry_timings,
             destination,
@@ -154,7 +154,7 @@ class TransactionStore(SQLBaseStore):
         return result
 
     def _get_destination_retry_timings(self, txn, destination):
-        result = self.db.simple_select_one_txn(
+        result = self.db_pool.simple_select_one_txn(
             txn,
             table="destinations",
             keyvalues={"destination": destination},
@@ -181,7 +181,7 @@ class TransactionStore(SQLBaseStore):
         """
 
         self._destination_retry_cache.pop(destination, None)
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "set_destination_retry_timings",
             self._set_destination_retry_timings,
             destination,
@@ -221,7 +221,7 @@ class TransactionStore(SQLBaseStore):
         # We need to be careful here as the data may have changed from under us
         # due to a worker setting the timings.
 
-        prev_row = self.db.simple_select_one_txn(
+        prev_row = self.db_pool.simple_select_one_txn(
             txn,
             table="destinations",
             keyvalues={"destination": destination},
@@ -230,7 +230,7 @@ class TransactionStore(SQLBaseStore):
         )
 
         if not prev_row:
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="destinations",
                 values={
@@ -241,7 +241,7 @@ class TransactionStore(SQLBaseStore):
                 },
             )
         elif retry_interval == 0 or prev_row["retry_interval"] < retry_interval:
-            self.db.simple_update_one_txn(
+            self.db_pool.simple_update_one_txn(
                 txn,
                 "destinations",
                 keyvalues={"destination": destination},
@@ -264,6 +264,6 @@ class TransactionStore(SQLBaseStore):
         def _cleanup_transactions_txn(txn):
             txn.execute("DELETE FROM received_transactions WHERE ts < ?", (month_ago,))
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "_cleanup_transactions", _cleanup_transactions_txn
         )
diff --git a/synapse/storage/data_stores/main/ui_auth.py b/synapse/storage/databases/main/ui_auth.py
index 5f1b919748..37276f73f8 100644
--- a/synapse/storage/data_stores/main/ui_auth.py
+++ b/synapse/storage/databases/main/ui_auth.py
@@ -81,7 +81,7 @@ class UIAuthWorkerStore(SQLBaseStore):
             session_id = stringutils.random_string(24)
 
             try:
-                await self.db.simple_insert(
+                await self.db_pool.simple_insert(
                     table="ui_auth_sessions",
                     values={
                         "session_id": session_id,
@@ -97,7 +97,7 @@ class UIAuthWorkerStore(SQLBaseStore):
                 return UIAuthSessionData(
                     session_id, clientdict, uri, method, description
                 )
-            except self.db.engine.module.IntegrityError:
+            except self.db_pool.engine.module.IntegrityError:
                 attempts += 1
         raise StoreError(500, "Couldn't generate a session ID.")
 
@@ -111,7 +111,7 @@ class UIAuthWorkerStore(SQLBaseStore):
         Raises:
             StoreError if the session is not found.
         """
-        result = await self.db.simple_select_one(
+        result = await self.db_pool.simple_select_one(
             table="ui_auth_sessions",
             keyvalues={"session_id": session_id},
             retcols=("clientdict", "uri", "method", "description"),
@@ -140,13 +140,13 @@ class UIAuthWorkerStore(SQLBaseStore):
         # Note that we need to allow for the same stage to complete multiple
         # times here so that registration is idempotent.
         try:
-            await self.db.simple_upsert(
+            await self.db_pool.simple_upsert(
                 table="ui_auth_sessions_credentials",
                 keyvalues={"session_id": session_id, "stage_type": stage_type},
                 values={"result": json.dumps(result)},
                 desc="mark_ui_auth_stage_complete",
             )
-        except self.db.engine.module.IntegrityError:
+        except self.db_pool.engine.module.IntegrityError:
             raise StoreError(400, "Unknown session ID: %s" % (session_id,))
 
     async def get_completed_ui_auth_stages(
@@ -162,7 +162,7 @@ class UIAuthWorkerStore(SQLBaseStore):
             that auth-type.
         """
         results = {}
-        for row in await self.db.simple_select_list(
+        for row in await self.db_pool.simple_select_list(
             table="ui_auth_sessions_credentials",
             keyvalues={"session_id": session_id},
             retcols=("stage_type", "result"),
@@ -186,7 +186,7 @@ class UIAuthWorkerStore(SQLBaseStore):
         # The clientdict gets stored as JSON.
         clientdict_json = json.dumps(clientdict)
 
-        await self.db.simple_update_one(
+        await self.db_pool.simple_update_one(
             table="ui_auth_sessions",
             keyvalues={"session_id": session_id},
             updatevalues={"clientdict": clientdict_json},
@@ -206,7 +206,7 @@ class UIAuthWorkerStore(SQLBaseStore):
         Raises:
             StoreError if the session cannot be found.
         """
-        await self.db.runInteraction(
+        await self.db_pool.runInteraction(
             "set_ui_auth_session_data",
             self._set_ui_auth_session_data_txn,
             session_id,
@@ -216,7 +216,7 @@ class UIAuthWorkerStore(SQLBaseStore):
 
     def _set_ui_auth_session_data_txn(self, txn, session_id: str, key: str, value: Any):
         # Get the current value.
-        result = self.db.simple_select_one_txn(
+        result = self.db_pool.simple_select_one_txn(
             txn,
             table="ui_auth_sessions",
             keyvalues={"session_id": session_id},
@@ -227,7 +227,7 @@ class UIAuthWorkerStore(SQLBaseStore):
         serverdict = db_to_json(result["serverdict"])
         serverdict[key] = value
 
-        self.db.simple_update_one_txn(
+        self.db_pool.simple_update_one_txn(
             txn,
             table="ui_auth_sessions",
             keyvalues={"session_id": session_id},
@@ -247,7 +247,7 @@ class UIAuthWorkerStore(SQLBaseStore):
         Raises:
             StoreError if the session cannot be found.
         """
-        result = await self.db.simple_select_one(
+        result = await self.db_pool.simple_select_one(
             table="ui_auth_sessions",
             keyvalues={"session_id": session_id},
             retcols=("serverdict",),
@@ -269,7 +269,7 @@ class UIAuthStore(UIAuthWorkerStore):
                 This is an epoch time in milliseconds.
 
         """
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "delete_old_ui_auth_sessions",
             self._delete_old_ui_auth_sessions_txn,
             expiration_time,
@@ -282,7 +282,7 @@ class UIAuthStore(UIAuthWorkerStore):
         session_ids = [r[0] for r in txn.fetchall()]
 
         # Delete the corresponding completed credentials.
-        self.db.simple_delete_many_txn(
+        self.db_pool.simple_delete_many_txn(
             txn,
             table="ui_auth_sessions_credentials",
             column="session_id",
@@ -291,7 +291,7 @@ class UIAuthStore(UIAuthWorkerStore):
         )
 
         # Finally, delete the sessions.
-        self.db.simple_delete_many_txn(
+        self.db_pool.simple_delete_many_txn(
             txn,
             table="ui_auth_sessions",
             column="session_id",
diff --git a/synapse/storage/data_stores/main/user_directory.py b/synapse/storage/databases/main/user_directory.py
index 942e51fd3a..d73a8e8ab9 100644
--- a/synapse/storage/data_stores/main/user_directory.py
+++ b/synapse/storage/databases/main/user_directory.py
@@ -19,9 +19,9 @@ import re
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, JoinRules
-from synapse.storage.data_stores.main.state import StateFilter
-from synapse.storage.data_stores.main.state_deltas import StateDeltasStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.main.state import StateFilter
+from synapse.storage.databases.main.state_deltas import StateDeltasStore
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 from synapse.types import get_domain_from_id, get_localpart_from_id
 from synapse.util.caches.descriptors import cached
@@ -38,24 +38,24 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
     # add_users_who_share_private_rooms?
     SHARE_PRIVATE_WORKING_SET = 500
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(UserDirectoryBackgroundUpdateStore, self).__init__(database, db_conn, hs)
 
         self.server_name = hs.hostname
 
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "populate_user_directory_createtables",
             self._populate_user_directory_createtables,
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "populate_user_directory_process_rooms",
             self._populate_user_directory_process_rooms,
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "populate_user_directory_process_users",
             self._populate_user_directory_process_users,
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             "populate_user_directory_cleanup", self._populate_user_directory_cleanup
         )
 
@@ -85,7 +85,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             """
             txn.execute(sql)
             rooms = [{"room_id": x[0], "events": x[1]} for x in txn.fetchall()]
-            self.db.simple_insert_many_txn(txn, TEMP_TABLE + "_rooms", rooms)
+            self.db_pool.simple_insert_many_txn(txn, TEMP_TABLE + "_rooms", rooms)
             del rooms
 
             # If search all users is on, get all the users we want to add.
@@ -100,15 +100,17 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
                 txn.execute("SELECT name FROM users")
                 users = [{"user_id": x[0]} for x in txn.fetchall()]
 
-                self.db.simple_insert_many_txn(txn, TEMP_TABLE + "_users", users)
+                self.db_pool.simple_insert_many_txn(txn, TEMP_TABLE + "_users", users)
 
         new_pos = yield self.get_max_stream_id_in_current_state_deltas()
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "populate_user_directory_temp_build", _make_staging_area
         )
-        yield self.db.simple_insert(TEMP_TABLE + "_position", {"position": new_pos})
+        yield self.db_pool.simple_insert(
+            TEMP_TABLE + "_position", {"position": new_pos}
+        )
 
-        yield self.db.updates._end_background_update(
+        yield self.db_pool.updates._end_background_update(
             "populate_user_directory_createtables"
         )
         return 1
@@ -118,7 +120,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
         """
         Update the user directory stream position, then clean up the old tables.
         """
-        position = yield self.db.simple_select_one_onecol(
+        position = yield self.db_pool.simple_select_one_onecol(
             TEMP_TABLE + "_position", None, "position"
         )
         yield self.update_user_directory_stream_pos(position)
@@ -128,11 +130,13 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             txn.execute("DROP TABLE IF EXISTS " + TEMP_TABLE + "_users")
             txn.execute("DROP TABLE IF EXISTS " + TEMP_TABLE + "_position")
 
-        yield self.db.runInteraction(
+        yield self.db_pool.runInteraction(
             "populate_user_directory_cleanup", _delete_staging_area
         )
 
-        yield self.db.updates._end_background_update("populate_user_directory_cleanup")
+        yield self.db_pool.updates._end_background_update(
+            "populate_user_directory_cleanup"
+        )
         return 1
 
     @defer.inlineCallbacks
@@ -172,13 +176,13 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
 
             return rooms_to_work_on
 
-        rooms_to_work_on = yield self.db.runInteraction(
+        rooms_to_work_on = yield self.db_pool.runInteraction(
             "populate_user_directory_temp_read", _get_next_batch
         )
 
         # No more rooms -- complete the transaction.
         if not rooms_to_work_on:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 "populate_user_directory_process_rooms"
             )
             return 1
@@ -249,12 +253,14 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
                         to_insert.clear()
 
             # We've finished a room. Delete it from the table.
-            yield self.db.simple_delete_one(TEMP_TABLE + "_rooms", {"room_id": room_id})
+            yield self.db_pool.simple_delete_one(
+                TEMP_TABLE + "_rooms", {"room_id": room_id}
+            )
             # Update the remaining counter.
             progress["remaining"] -= 1
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "populate_user_directory",
-                self.db.updates._background_update_progress_txn,
+                self.db_pool.updates._background_update_progress_txn,
                 "populate_user_directory_process_rooms",
                 progress,
             )
@@ -273,7 +279,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
         If search_all_users is enabled, add all of the users to the user directory.
         """
         if not self.hs.config.user_directory_search_all_users:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 "populate_user_directory_process_users"
             )
             return 1
@@ -299,13 +305,13 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
 
             return users_to_work_on
 
-        users_to_work_on = yield self.db.runInteraction(
+        users_to_work_on = yield self.db_pool.runInteraction(
             "populate_user_directory_temp_read", _get_next_batch
         )
 
         # No more users -- complete the transaction.
         if not users_to_work_on:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 "populate_user_directory_process_users"
             )
             return 1
@@ -322,12 +328,14 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             )
 
             # We've finished processing a user. Delete it from the table.
-            yield self.db.simple_delete_one(TEMP_TABLE + "_users", {"user_id": user_id})
+            yield self.db_pool.simple_delete_one(
+                TEMP_TABLE + "_users", {"user_id": user_id}
+            )
             # Update the remaining counter.
             progress["remaining"] -= 1
-            yield self.db.runInteraction(
+            yield self.db_pool.runInteraction(
                 "populate_user_directory",
-                self.db.updates._background_update_progress_txn,
+                self.db_pool.updates._background_update_progress_txn,
                 "populate_user_directory_process_users",
                 progress,
             )
@@ -371,7 +379,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
         """
 
         def _update_profile_in_user_dir_txn(txn):
-            new_entry = self.db.simple_upsert_txn(
+            new_entry = self.db_pool.simple_upsert_txn(
                 txn,
                 table="user_directory",
                 keyvalues={"user_id": user_id},
@@ -445,7 +453,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
                         )
             elif isinstance(self.database_engine, Sqlite3Engine):
                 value = "%s %s" % (user_id, display_name) if display_name else user_id
-                self.db.simple_upsert_txn(
+                self.db_pool.simple_upsert_txn(
                     txn,
                     table="user_directory_search",
                     keyvalues={"user_id": user_id},
@@ -458,7 +466,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
 
             txn.call_after(self.get_user_in_directory.invalidate, (user_id,))
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "update_profile_in_user_dir", _update_profile_in_user_dir_txn
         )
 
@@ -472,7 +480,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
         """
 
         def _add_users_who_share_room_txn(txn):
-            self.db.simple_upsert_many_txn(
+            self.db_pool.simple_upsert_many_txn(
                 txn,
                 table="users_who_share_private_rooms",
                 key_names=["user_id", "other_user_id", "room_id"],
@@ -484,7 +492,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
                 value_values=None,
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "add_users_who_share_room", _add_users_who_share_room_txn
         )
 
@@ -499,7 +507,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
 
         def _add_users_in_public_rooms_txn(txn):
 
-            self.db.simple_upsert_many_txn(
+            self.db_pool.simple_upsert_many_txn(
                 txn,
                 table="users_in_public_rooms",
                 key_names=["user_id", "room_id"],
@@ -508,7 +516,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
                 value_values=None,
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "add_users_in_public_rooms", _add_users_in_public_rooms_txn
         )
 
@@ -523,13 +531,13 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
             txn.execute("DELETE FROM users_who_share_private_rooms")
             txn.call_after(self.get_user_in_directory.invalidate_all)
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "delete_all_from_user_dir", _delete_all_from_user_dir_txn
         )
 
     @cached()
     def get_user_in_directory(self, user_id):
-        return self.db.simple_select_one(
+        return self.db_pool.simple_select_one(
             table="user_directory",
             keyvalues={"user_id": user_id},
             retcols=("display_name", "avatar_url"),
@@ -538,7 +546,7 @@ class UserDirectoryBackgroundUpdateStore(StateDeltasStore):
         )
 
     def update_user_directory_stream_pos(self, stream_id):
-        return self.db.simple_update_one(
+        return self.db_pool.simple_update_one(
             table="user_directory_stream_pos",
             keyvalues={},
             updatevalues={"stream_id": stream_id},
@@ -552,47 +560,49 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
     # add_users_who_share_private_rooms?
     SHARE_PRIVATE_WORKING_SET = 500
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(UserDirectoryStore, self).__init__(database, db_conn, hs)
 
     def remove_from_user_dir(self, user_id):
         def _remove_from_user_dir_txn(txn):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn, table="user_directory", keyvalues={"user_id": user_id}
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn, table="user_directory_search", keyvalues={"user_id": user_id}
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn, table="users_in_public_rooms", keyvalues={"user_id": user_id}
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="users_who_share_private_rooms",
                 keyvalues={"user_id": user_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="users_who_share_private_rooms",
                 keyvalues={"other_user_id": user_id},
             )
             txn.call_after(self.get_user_in_directory.invalidate, (user_id,))
 
-        return self.db.runInteraction("remove_from_user_dir", _remove_from_user_dir_txn)
+        return self.db_pool.runInteraction(
+            "remove_from_user_dir", _remove_from_user_dir_txn
+        )
 
     @defer.inlineCallbacks
     def get_users_in_dir_due_to_room(self, room_id):
         """Get all user_ids that are in the room directory because they're
         in the given room_id
         """
-        user_ids_share_pub = yield self.db.simple_select_onecol(
+        user_ids_share_pub = yield self.db_pool.simple_select_onecol(
             table="users_in_public_rooms",
             keyvalues={"room_id": room_id},
             retcol="user_id",
             desc="get_users_in_dir_due_to_room",
         )
 
-        user_ids_share_priv = yield self.db.simple_select_onecol(
+        user_ids_share_priv = yield self.db_pool.simple_select_onecol(
             table="users_who_share_private_rooms",
             keyvalues={"room_id": room_id},
             retcol="other_user_id",
@@ -615,23 +625,23 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
         """
 
         def _remove_user_who_share_room_txn(txn):
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="users_who_share_private_rooms",
                 keyvalues={"user_id": user_id, "room_id": room_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="users_who_share_private_rooms",
                 keyvalues={"other_user_id": user_id, "room_id": room_id},
             )
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn,
                 table="users_in_public_rooms",
                 keyvalues={"user_id": user_id, "room_id": room_id},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "remove_user_who_share_room", _remove_user_who_share_room_txn
         )
 
@@ -646,14 +656,14 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
         Returns:
             list: user_id
         """
-        rows = yield self.db.simple_select_onecol(
+        rows = yield self.db_pool.simple_select_onecol(
             table="users_who_share_private_rooms",
             keyvalues={"user_id": user_id},
             retcol="room_id",
             desc="get_rooms_user_is_in",
         )
 
-        pub_rows = yield self.db.simple_select_onecol(
+        pub_rows = yield self.db_pool.simple_select_onecol(
             table="users_in_public_rooms",
             keyvalues={"user_id": user_id},
             retcol="room_id",
@@ -684,14 +694,14 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
             ) f2 USING (room_id)
         """
 
-        rows = yield self.db.execute(
+        rows = yield self.db_pool.execute(
             "get_rooms_in_common_for_users", None, sql, user_id, other_user_id
         )
 
         return [room_id for room_id, in rows]
 
     def get_user_directory_stream_pos(self):
-        return self.db.simple_select_one_onecol(
+        return self.db_pool.simple_select_one_onecol(
             table="user_directory_stream_pos",
             keyvalues={},
             retcol="stream_id",
@@ -796,8 +806,8 @@ class UserDirectoryStore(UserDirectoryBackgroundUpdateStore):
             # This should be unreachable.
             raise Exception("Unrecognized database engine")
 
-        results = yield self.db.execute(
-            "search_user_dir", self.db.cursor_to_dict, sql, *args
+        results = yield self.db_pool.execute(
+            "search_user_dir", self.db_pool.cursor_to_dict, sql, *args
         )
 
         limited = len(results) > limit
diff --git a/synapse/storage/data_stores/main/user_erasure_store.py b/synapse/storage/databases/main/user_erasure_store.py
index d3038ff06d..ab6cb2c1f6 100644
--- a/synapse/storage/data_stores/main/user_erasure_store.py
+++ b/synapse/storage/databases/main/user_erasure_store.py
@@ -31,7 +31,7 @@ class UserErasureWorkerStore(SQLBaseStore):
         Returns:
             Deferred[bool]: True if the user has requested erasure
         """
-        return self.db.simple_select_onecol(
+        return self.db_pool.simple_select_onecol(
             table="erased_users",
             keyvalues={"user_id": user_id},
             retcol="1",
@@ -56,7 +56,7 @@ class UserErasureWorkerStore(SQLBaseStore):
         # iterate it multiple times, and (b) avoiding duplicates.
         user_ids = tuple(set(user_ids))
 
-        rows = yield self.db.simple_select_many_batch(
+        rows = yield self.db_pool.simple_select_many_batch(
             table="erased_users",
             column="user_id",
             iterable=user_ids,
@@ -88,7 +88,7 @@ class UserErasureStore(UserErasureWorkerStore):
 
             self._invalidate_cache_and_stream(txn, self.is_user_erased, (user_id,))
 
-        return self.db.runInteraction("mark_user_erased", f)
+        return self.db_pool.runInteraction("mark_user_erased", f)
 
     def mark_user_not_erased(self, user_id: str) -> None:
         """Indicate that user_id is no longer erased.
@@ -110,4 +110,4 @@ class UserErasureStore(UserErasureWorkerStore):
 
             self._invalidate_cache_and_stream(txn, self.is_user_erased, (user_id,))
 
-        return self.db.runInteraction("mark_user_not_erased", f)
+        return self.db_pool.runInteraction("mark_user_not_erased", f)
diff --git a/synapse/storage/data_stores/state/__init__.py b/synapse/storage/databases/state/__init__.py
index 86e09f6229..c90d022899 100644
--- a/synapse/storage/data_stores/state/__init__.py
+++ b/synapse/storage/databases/state/__init__.py
@@ -13,4 +13,4 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from synapse.storage.data_stores.state.store import StateGroupDataStore  # noqa: F401
+from synapse.storage.databases.state.store import StateGroupDataStore  # noqa: F401
diff --git a/synapse/storage/data_stores/state/bg_updates.py b/synapse/storage/databases/state/bg_updates.py
index be1fe97d79..1e2d584098 100644
--- a/synapse/storage/data_stores/state/bg_updates.py
+++ b/synapse/storage/databases/state/bg_updates.py
@@ -18,7 +18,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.state import StateFilter
 
@@ -62,7 +62,7 @@ class StateGroupBackgroundUpdateStore(SQLBaseStore):
             count = 0
 
             while next_group:
-                next_group = self.db.simple_select_one_onecol_txn(
+                next_group = self.db_pool.simple_select_one_onecol_txn(
                     txn,
                     table="state_group_edges",
                     keyvalues={"state_group": next_group},
@@ -165,7 +165,7 @@ class StateGroupBackgroundUpdateStore(SQLBaseStore):
                     ):
                         break
 
-                    next_group = self.db.simple_select_one_onecol_txn(
+                    next_group = self.db_pool.simple_select_one_onecol_txn(
                         txn,
                         table="state_group_edges",
                         keyvalues={"state_group": next_group},
@@ -182,16 +182,16 @@ class StateBackgroundUpdateStore(StateGroupBackgroundUpdateStore):
     STATE_GROUP_INDEX_UPDATE_NAME = "state_group_state_type_index"
     STATE_GROUPS_ROOM_INDEX_UPDATE_NAME = "state_groups_room_id_idx"
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(StateBackgroundUpdateStore, self).__init__(database, db_conn, hs)
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.STATE_GROUP_DEDUPLICATION_UPDATE_NAME,
             self._background_deduplicate_state,
         )
-        self.db.updates.register_background_update_handler(
+        self.db_pool.updates.register_background_update_handler(
             self.STATE_GROUP_INDEX_UPDATE_NAME, self._background_index_state
         )
-        self.db.updates.register_background_index_update(
+        self.db_pool.updates.register_background_index_update(
             self.STATE_GROUPS_ROOM_INDEX_UPDATE_NAME,
             index_name="state_groups_room_id_idx",
             table="state_groups",
@@ -212,7 +212,7 @@ class StateBackgroundUpdateStore(StateGroupBackgroundUpdateStore):
         batch_size = max(1, int(batch_size / BATCH_SIZE_SCALE_FACTOR))
 
         if max_group is None:
-            rows = yield self.db.execute(
+            rows = yield self.db_pool.execute(
                 "_background_deduplicate_state",
                 None,
                 "SELECT coalesce(max(id), 0) FROM state_groups",
@@ -282,13 +282,13 @@ class StateBackgroundUpdateStore(StateGroupBackgroundUpdateStore):
                             if prev_state.get(key, None) != value
                         }
 
-                        self.db.simple_delete_txn(
+                        self.db_pool.simple_delete_txn(
                             txn,
                             table="state_group_edges",
                             keyvalues={"state_group": state_group},
                         )
 
-                        self.db.simple_insert_txn(
+                        self.db_pool.simple_insert_txn(
                             txn,
                             table="state_group_edges",
                             values={
@@ -297,13 +297,13 @@ class StateBackgroundUpdateStore(StateGroupBackgroundUpdateStore):
                             },
                         )
 
-                        self.db.simple_delete_txn(
+                        self.db_pool.simple_delete_txn(
                             txn,
                             table="state_groups_state",
                             keyvalues={"state_group": state_group},
                         )
 
-                        self.db.simple_insert_many_txn(
+                        self.db_pool.simple_insert_many_txn(
                             txn,
                             table="state_groups_state",
                             values=[
@@ -324,18 +324,18 @@ class StateBackgroundUpdateStore(StateGroupBackgroundUpdateStore):
                 "max_group": max_group,
             }
 
-            self.db.updates._background_update_progress_txn(
+            self.db_pool.updates._background_update_progress_txn(
                 txn, self.STATE_GROUP_DEDUPLICATION_UPDATE_NAME, progress
             )
 
             return False, batch_size
 
-        finished, result = yield self.db.runInteraction(
+        finished, result = yield self.db_pool.runInteraction(
             self.STATE_GROUP_DEDUPLICATION_UPDATE_NAME, reindex_txn
         )
 
         if finished:
-            yield self.db.updates._end_background_update(
+            yield self.db_pool.updates._end_background_update(
                 self.STATE_GROUP_DEDUPLICATION_UPDATE_NAME
             )
 
@@ -365,8 +365,10 @@ class StateBackgroundUpdateStore(StateGroupBackgroundUpdateStore):
                 )
                 txn.execute("DROP INDEX IF EXISTS state_groups_state_id")
 
-        yield self.db.runWithConnection(reindex_txn)
+        yield self.db_pool.runWithConnection(reindex_txn)
 
-        yield self.db.updates._end_background_update(self.STATE_GROUP_INDEX_UPDATE_NAME)
+        yield self.db_pool.updates._end_background_update(
+            self.STATE_GROUP_INDEX_UPDATE_NAME
+        )
 
         return 1
diff --git a/synapse/storage/data_stores/state/schema/delta/23/drop_state_index.sql b/synapse/storage/databases/state/schema/delta/23/drop_state_index.sql
index ae09fa0065..ae09fa0065 100644
--- a/synapse/storage/data_stores/state/schema/delta/23/drop_state_index.sql
+++ b/synapse/storage/databases/state/schema/delta/23/drop_state_index.sql
diff --git a/synapse/storage/data_stores/state/schema/delta/30/state_stream.sql b/synapse/storage/databases/state/schema/delta/30/state_stream.sql
index e85699e82e..e85699e82e 100644
--- a/synapse/storage/data_stores/state/schema/delta/30/state_stream.sql
+++ b/synapse/storage/databases/state/schema/delta/30/state_stream.sql
diff --git a/synapse/storage/data_stores/state/schema/delta/32/remove_state_indices.sql b/synapse/storage/databases/state/schema/delta/32/remove_state_indices.sql
index 1450313bfa..1450313bfa 100644
--- a/synapse/storage/data_stores/state/schema/delta/32/remove_state_indices.sql
+++ b/synapse/storage/databases/state/schema/delta/32/remove_state_indices.sql
diff --git a/synapse/storage/data_stores/state/schema/delta/35/add_state_index.sql b/synapse/storage/databases/state/schema/delta/35/add_state_index.sql
index 33980d02f0..33980d02f0 100644
--- a/synapse/storage/data_stores/state/schema/delta/35/add_state_index.sql
+++ b/synapse/storage/databases/state/schema/delta/35/add_state_index.sql
diff --git a/synapse/storage/data_stores/state/schema/delta/35/state.sql b/synapse/storage/databases/state/schema/delta/35/state.sql
index 0f1fa68a89..0f1fa68a89 100644
--- a/synapse/storage/data_stores/state/schema/delta/35/state.sql
+++ b/synapse/storage/databases/state/schema/delta/35/state.sql
diff --git a/synapse/storage/data_stores/state/schema/delta/35/state_dedupe.sql b/synapse/storage/databases/state/schema/delta/35/state_dedupe.sql
index 97e5067ef4..97e5067ef4 100644
--- a/synapse/storage/data_stores/state/schema/delta/35/state_dedupe.sql
+++ b/synapse/storage/databases/state/schema/delta/35/state_dedupe.sql
diff --git a/synapse/storage/data_stores/state/schema/delta/47/state_group_seq.py b/synapse/storage/databases/state/schema/delta/47/state_group_seq.py
index 9fd1ccf6f7..9fd1ccf6f7 100644
--- a/synapse/storage/data_stores/state/schema/delta/47/state_group_seq.py
+++ b/synapse/storage/databases/state/schema/delta/47/state_group_seq.py
diff --git a/synapse/storage/data_stores/state/schema/delta/56/state_group_room_idx.sql b/synapse/storage/databases/state/schema/delta/56/state_group_room_idx.sql
index 7916ef18b2..7916ef18b2 100644
--- a/synapse/storage/data_stores/state/schema/delta/56/state_group_room_idx.sql
+++ b/synapse/storage/databases/state/schema/delta/56/state_group_room_idx.sql
diff --git a/synapse/storage/data_stores/state/schema/full_schemas/54/full.sql b/synapse/storage/databases/state/schema/full_schemas/54/full.sql
index 35f97d6b3d..35f97d6b3d 100644
--- a/synapse/storage/data_stores/state/schema/full_schemas/54/full.sql
+++ b/synapse/storage/databases/state/schema/full_schemas/54/full.sql
diff --git a/synapse/storage/data_stores/state/schema/full_schemas/54/sequence.sql.postgres b/synapse/storage/databases/state/schema/full_schemas/54/sequence.sql.postgres
index fcd926c9fb..fcd926c9fb 100644
--- a/synapse/storage/data_stores/state/schema/full_schemas/54/sequence.sql.postgres
+++ b/synapse/storage/databases/state/schema/full_schemas/54/sequence.sql.postgres
diff --git a/synapse/storage/data_stores/state/store.py b/synapse/storage/databases/state/store.py
index 7dada7f75f..7f104ad936 100644
--- a/synapse/storage/data_stores/state/store.py
+++ b/synapse/storage/databases/state/store.py
@@ -21,8 +21,8 @@ from twisted.internet import defer
 
 from synapse.api.constants import EventTypes
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.data_stores.state.bg_updates import StateBackgroundUpdateStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
+from synapse.storage.databases.state.bg_updates import StateBackgroundUpdateStore
 from synapse.storage.state import StateFilter
 from synapse.storage.types import Cursor
 from synapse.storage.util.sequence import build_sequence_generator
@@ -53,7 +53,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
     """A data store for fetching/storing state groups.
     """
 
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(StateGroupDataStore, self).__init__(database, db_conn, hs)
 
         # Originally the state store used a single DictionaryCache to cache the
@@ -112,7 +112,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
         """
 
         def _get_state_group_delta_txn(txn):
-            prev_group = self.db.simple_select_one_onecol_txn(
+            prev_group = self.db_pool.simple_select_one_onecol_txn(
                 txn,
                 table="state_group_edges",
                 keyvalues={"state_group": state_group},
@@ -123,7 +123,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
             if not prev_group:
                 return _GetStateGroupDelta(None, None)
 
-            delta_ids = self.db.simple_select_list_txn(
+            delta_ids = self.db_pool.simple_select_list_txn(
                 txn,
                 table="state_groups_state",
                 keyvalues={"state_group": state_group},
@@ -135,7 +135,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
                 {(row["type"], row["state_key"]): row["event_id"] for row in delta_ids},
             )
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "get_state_group_delta", _get_state_group_delta_txn
         )
 
@@ -156,7 +156,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
 
         chunks = [groups[i : i + 100] for i in range(0, len(groups), 100)]
         for chunk in chunks:
-            res = await self.db.runInteraction(
+            res = await self.db_pool.runInteraction(
                 "_get_state_groups_from_groups",
                 self._get_state_groups_from_groups_txn,
                 chunk,
@@ -393,7 +393,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
 
             state_group = self._state_group_seq_gen.get_next_id_txn(txn)
 
-            self.db.simple_insert_txn(
+            self.db_pool.simple_insert_txn(
                 txn,
                 table="state_groups",
                 values={"id": state_group, "room_id": room_id, "event_id": event_id},
@@ -402,7 +402,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
             # We persist as a delta if we can, while also ensuring the chain
             # of deltas isn't tooo long, as otherwise read performance degrades.
             if prev_group:
-                is_in_db = self.db.simple_select_one_onecol_txn(
+                is_in_db = self.db_pool.simple_select_one_onecol_txn(
                     txn,
                     table="state_groups",
                     keyvalues={"id": prev_group},
@@ -417,13 +417,13 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
 
                 potential_hops = self._count_state_group_hops_txn(txn, prev_group)
             if prev_group and potential_hops < MAX_STATE_DELTA_HOPS:
-                self.db.simple_insert_txn(
+                self.db_pool.simple_insert_txn(
                     txn,
                     table="state_group_edges",
                     values={"state_group": state_group, "prev_state_group": prev_group},
                 )
 
-                self.db.simple_insert_many_txn(
+                self.db_pool.simple_insert_many_txn(
                     txn,
                     table="state_groups_state",
                     values=[
@@ -438,7 +438,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
                     ],
                 )
             else:
-                self.db.simple_insert_many_txn(
+                self.db_pool.simple_insert_many_txn(
                     txn,
                     table="state_groups_state",
                     values=[
@@ -484,7 +484,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
 
             return state_group
 
-        return self.db.runInteraction("store_state_group", _store_state_group_txn)
+        return self.db_pool.runInteraction("store_state_group", _store_state_group_txn)
 
     def purge_unreferenced_state_groups(
         self, room_id: str, state_groups_to_delete
@@ -499,7 +499,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
                 to delete.
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "purge_unreferenced_state_groups",
             self._purge_unreferenced_state_groups,
             room_id,
@@ -511,7 +511,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
             "[purge] found %i state groups to delete", len(state_groups_to_delete)
         )
 
-        rows = self.db.simple_select_many_txn(
+        rows = self.db_pool.simple_select_many_txn(
             txn,
             table="state_group_edges",
             column="prev_state_group",
@@ -538,15 +538,15 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
             curr_state = self._get_state_groups_from_groups_txn(txn, [sg])
             curr_state = curr_state[sg]
 
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn, table="state_groups_state", keyvalues={"state_group": sg}
             )
 
-            self.db.simple_delete_txn(
+            self.db_pool.simple_delete_txn(
                 txn, table="state_group_edges", keyvalues={"state_group": sg}
             )
 
-            self.db.simple_insert_many_txn(
+            self.db_pool.simple_insert_many_txn(
                 txn,
                 table="state_groups_state",
                 values=[
@@ -583,7 +583,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
             A mapping from state group to previous state group.
         """
 
-        rows = await self.db.simple_select_many_batch(
+        rows = await self.db_pool.simple_select_many_batch(
             table="state_group_edges",
             column="prev_state_group",
             iterable=state_groups,
@@ -602,7 +602,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
             state_groups_to_delete (list[int]): State groups to delete
         """
 
-        return self.db.runInteraction(
+        return self.db_pool.runInteraction(
             "purge_room_state",
             self._purge_room_state_txn,
             room_id,
@@ -613,7 +613,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
         # first we have to delete the state groups states
         logger.info("[purge] removing %s from state_groups_state", room_id)
 
-        self.db.simple_delete_many_txn(
+        self.db_pool.simple_delete_many_txn(
             txn,
             table="state_groups_state",
             column="state_group",
@@ -624,7 +624,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
         # ... and the state group edges
         logger.info("[purge] removing %s from state_group_edges", room_id)
 
-        self.db.simple_delete_many_txn(
+        self.db_pool.simple_delete_many_txn(
             txn,
             table="state_group_edges",
             column="state_group",
@@ -635,7 +635,7 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
         # ... and the state groups
         logger.info("[purge] removing %s from state_groups", room_id)
 
-        self.db.simple_delete_many_txn(
+        self.db_pool.simple_delete_many_txn(
             txn,
             table="state_groups",
             column="id",
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index 4a164834d9..f15b95e633 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -29,8 +29,8 @@ from synapse.events import EventBase
 from synapse.events.snapshot import EventContext
 from synapse.logging.context import PreserveLoggingContext, make_deferred_yieldable
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.storage.data_stores import DataStores
-from synapse.storage.data_stores.main.events import DeltaState
+from synapse.storage.databases import Databases
+from synapse.storage.databases.main.events import DeltaState
 from synapse.types import StateMap
 from synapse.util.async_helpers import ObservableDeferred
 from synapse.util.metrics import Measure
@@ -179,7 +179,7 @@ class EventsPersistenceStorage(object):
     current state and forward extremity changes.
     """
 
-    def __init__(self, hs, stores: DataStores):
+    def __init__(self, hs, stores: Databases):
         # We ultimately want to split out the state store from the main store,
         # so we use separate variables here even though they point to the same
         # store for now.
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index 9cc3b51fe6..1c5f305132 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -47,8 +47,8 @@ class UpgradeDatabaseException(PrepareDatabaseException):
     pass
 
 
-def prepare_database(db_conn, database_engine, config, data_stores=["main", "state"]):
-    """Prepares a database for usage. Will either create all necessary tables
+def prepare_database(db_conn, database_engine, config, databases=["main", "state"]):
+    """Prepares a physical database for usage. Will either create all necessary tables
     or upgrade from an older schema version.
 
     If `config` is None then prepare_database will assert that no upgrade is
@@ -60,8 +60,8 @@ def prepare_database(db_conn, database_engine, config, data_stores=["main", "sta
         config (synapse.config.homeserver.HomeServerConfig|None):
             application config, or None if we are connecting to an existing
             database which we expect to be configured already
-        data_stores (list[str]): The name of the data stores that will be used
-            with this database. Defaults to all data stores.
+        databases (list[str]): The name of the databases that will be used
+            with this physical database. Defaults to all databases.
     """
 
     try:
@@ -87,10 +87,10 @@ def prepare_database(db_conn, database_engine, config, data_stores=["main", "sta
                     upgraded,
                     database_engine,
                     config,
-                    data_stores=data_stores,
+                    databases=databases,
                 )
         else:
-            _setup_new_database(cur, database_engine, data_stores=data_stores)
+            _setup_new_database(cur, database_engine, databases=databases)
 
         # check if any of our configured dynamic modules want a database
         if config is not None:
@@ -103,9 +103,9 @@ def prepare_database(db_conn, database_engine, config, data_stores=["main", "sta
         raise
 
 
-def _setup_new_database(cur, database_engine, data_stores):
-    """Sets up the database by finding a base set of "full schemas" and then
-    applying any necessary deltas, including schemas from the given data
+def _setup_new_database(cur, database_engine, databases):
+    """Sets up the physical database by finding a base set of "full schemas" and
+    then applying any necessary deltas, including schemas from the given data
     stores.
 
     The "full_schemas" directory has subdirectories named after versions. This
@@ -138,8 +138,8 @@ def _setup_new_database(cur, database_engine, data_stores):
     Args:
         cur (Cursor): a database cursor
         database_engine (DatabaseEngine)
-        data_stores (list[str]): The names of the data stores to instantiate
-            on the given database.
+        databases (list[str]): The names of the databases to instantiate
+            on the given physical database.
     """
 
     # We're about to set up a brand new database so we check that its
@@ -176,13 +176,13 @@ def _setup_new_database(cur, database_engine, data_stores):
     directories.extend(
         os.path.join(
             dir_path,
-            "data_stores",
-            data_store,
+            "databases",
+            database,
             "schema",
             "full_schemas",
             str(max_current_ver),
         )
-        for data_store in data_stores
+        for database in databases
     )
 
     directory_entries = []
@@ -219,7 +219,7 @@ def _setup_new_database(cur, database_engine, data_stores):
         upgraded=False,
         database_engine=database_engine,
         config=None,
-        data_stores=data_stores,
+        databases=databases,
         is_empty=True,
     )
 
@@ -231,10 +231,10 @@ def _upgrade_existing_database(
     upgraded,
     database_engine,
     config,
-    data_stores,
+    databases,
     is_empty=False,
 ):
-    """Upgrades an existing database.
+    """Upgrades an existing physical database.
 
     Delta files can either be SQL stored in *.sql files, or python modules
     in *.py.
@@ -285,8 +285,8 @@ def _upgrade_existing_database(
         config (synapse.config.homeserver.HomeServerConfig|None):
             None if we are initialising a blank database, otherwise the application
             config
-        data_stores (list[str]): The names of the data stores to instantiate
-            on the given database.
+        databases (list[str]): The names of the databases to instantiate
+            on the given physical database.
         is_empty (bool): Is this a blank database? I.e. do we need to run the
             upgrade portions of the delta scripts.
     """
@@ -303,8 +303,8 @@ def _upgrade_existing_database(
 
     # some of the deltas assume that config.server_name is set correctly, so now
     # is a good time to run the sanity check.
-    if not is_empty and "main" in data_stores:
-        from synapse.storage.data_stores.main import check_database_before_upgrade
+    if not is_empty and "main" in databases:
+        from synapse.storage.databases.main import check_database_before_upgrade
 
         check_database_before_upgrade(cur, database_engine, config)
 
@@ -330,11 +330,9 @@ def _upgrade_existing_database(
         # First we find the directories to search in
         delta_dir = os.path.join(dir_path, "schema", "delta", str(v))
         directories = [delta_dir]
-        for data_store in data_stores:
+        for database in databases:
             directories.append(
-                os.path.join(
-                    dir_path, "data_stores", data_store, "schema", "delta", str(v)
-                )
+                os.path.join(dir_path, "databases", database, "schema", "delta", str(v))
             )
 
         # Used to check if we have any duplicate file names
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index 787cebfbec..e2ddd01290 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -20,7 +20,7 @@ from typing import Dict, Set, Tuple
 
 from typing_extensions import Deque
 
-from synapse.storage.database import Database, LoggingTransaction
+from synapse.storage.database import DatabasePool, LoggingTransaction
 from synapse.storage.util.sequence import PostgresSequenceGenerator
 
 
@@ -239,7 +239,7 @@ class MultiWriterIdGenerator:
     def __init__(
         self,
         db_conn,
-        db: Database,
+        db: DatabasePool,
         instance_name: str,
         table: str,
         instance_column: str,
diff --git a/synmark/__init__.py b/synmark/__init__.py
index afe4fad8cb..53698bd5ab 100644
--- a/synmark/__init__.py
+++ b/synmark/__init__.py
@@ -47,9 +47,9 @@ async def make_homeserver(reactor, config=None):
     stor = hs.get_datastore()
 
     # Run the database background updates.
-    if hasattr(stor.db.updates, "do_next_background_update"):
-        while not await stor.db.updates.has_completed_background_updates():
-            await stor.db.updates.do_next_background_update(1)
+    if hasattr(stor.db_pool.updates, "do_next_background_update"):
+        while not await stor.db_pool.updates.has_completed_background_updates():
+            await stor.db_pool.updates.do_next_background_update(1)
 
     def cleanup():
         for i in cleanup_tasks:
diff --git a/tests/handlers/test_stats.py b/tests/handlers/test_stats.py
index 5dc3795643..0e666492f6 100644
--- a/tests/handlers/test_stats.py
+++ b/tests/handlers/test_stats.py
@@ -15,7 +15,7 @@
 
 from synapse.rest import admin
 from synapse.rest.client.v1 import login, room
-from synapse.storage.data_stores.main import stats
+from synapse.storage.databases.main import stats
 
 from tests import unittest
 
@@ -42,16 +42,16 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         Add the background updates we need to run.
         """
         # Ugh, have to reset this flag
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
 
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {"update_name": "populate_stats_prepare", "progress_json": "{}"},
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_process_rooms_2",
@@ -61,7 +61,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_process_users",
@@ -71,7 +71,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_cleanup",
@@ -82,7 +82,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         )
 
     def get_all_room_state(self):
-        return self.store.db.simple_select_list(
+        return self.store.db_pool.simple_select_list(
             "room_stats_state", None, retcols=("name", "topic", "canonical_alias")
         )
 
@@ -96,7 +96,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         end_ts = self.store.quantise_stats_time(self.reactor.seconds() * 1000)
 
         return self.get_success(
-            self.store.db.simple_select_one(
+            self.store.db_pool.simple_select_one(
                 table + "_historical",
                 {id_col: stat_id, end_ts: end_ts},
                 cols,
@@ -109,10 +109,10 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         self._add_background_updates()
 
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
     def test_initial_room(self):
@@ -146,10 +146,10 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         self._add_background_updates()
 
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         r = self.get_success(self.get_all_room_state())
@@ -186,9 +186,9 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         # the position that the deltas should begin at, once they take over.
         self.hs.config.stats_enabled = True
         self.handler.stats_enabled = True
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
         self.get_success(
-            self.store.db.simple_update_one(
+            self.store.db_pool.simple_update_one(
                 table="stats_incremental_position",
                 keyvalues={},
                 updatevalues={"stream_id": 0},
@@ -196,17 +196,17 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         )
 
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {"update_name": "populate_stats_prepare", "progress_json": "{}"},
             )
         )
 
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         # Now, before the table is actually ingested, add some more events.
@@ -217,7 +217,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
 
         # Now do the initial ingestion.
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_process_rooms_2",
@@ -226,7 +226,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_cleanup",
@@ -236,12 +236,12 @@ class StatsRoomTests(unittest.HomeserverTestCase):
             )
         )
 
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         self.reactor.advance(86401)
@@ -703,15 +703,15 @@ class StatsRoomTests(unittest.HomeserverTestCase):
 
         # preparation stage of the initial background update
         # Ugh, have to reset this flag
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
 
         self.get_success(
-            self.store.db.simple_delete(
+            self.store.db_pool.simple_delete(
                 "room_stats_current", {"1": 1}, "test_delete_stats"
             )
         )
         self.get_success(
-            self.store.db.simple_delete(
+            self.store.db_pool.simple_delete(
                 "user_stats_current", {"1": 1}, "test_delete_stats"
             )
         )
@@ -723,9 +723,9 @@ class StatsRoomTests(unittest.HomeserverTestCase):
 
         # now do the background updates
 
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_process_rooms_2",
@@ -735,7 +735,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_process_users",
@@ -745,7 +745,7 @@ class StatsRoomTests(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_stats_cleanup",
@@ -756,10 +756,10 @@ class StatsRoomTests(unittest.HomeserverTestCase):
         )
 
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         r1stats_complete = self._get_current_stats("room", r1)
diff --git a/tests/handlers/test_user_directory.py b/tests/handlers/test_user_directory.py
index 23fcc372dd..31ed89a5cd 100644
--- a/tests/handlers/test_user_directory.py
+++ b/tests/handlers/test_user_directory.py
@@ -339,7 +339,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
 
     def get_users_in_public_rooms(self):
         r = self.get_success(
-            self.store.db.simple_select_list(
+            self.store.db_pool.simple_select_list(
                 "users_in_public_rooms", None, ("user_id", "room_id")
             )
         )
@@ -350,7 +350,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
 
     def get_users_who_share_private_rooms(self):
         return self.get_success(
-            self.store.db.simple_select_list(
+            self.store.db_pool.simple_select_list(
                 "users_who_share_private_rooms",
                 None,
                 ["user_id", "other_user_id", "room_id"],
@@ -362,10 +362,10 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
         Add the background updates we need to run.
         """
         # Ugh, have to reset this flag
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
 
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_user_directory_createtables",
@@ -374,7 +374,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_user_directory_process_rooms",
@@ -384,7 +384,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_user_directory_process_users",
@@ -394,7 +394,7 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 "background_updates",
                 {
                     "update_name": "populate_user_directory_cleanup",
@@ -437,10 +437,10 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
         self._add_background_updates()
 
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         shares_private = self.get_users_who_share_private_rooms()
@@ -476,10 +476,10 @@ class UserDirectoryTestCase(unittest.HomeserverTestCase):
         self._add_background_updates()
 
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         shares_private = self.get_users_who_share_private_rooms()
diff --git a/tests/replication/_base.py b/tests/replication/_base.py
index 06575ba0a6..ae60874ec3 100644
--- a/tests/replication/_base.py
+++ b/tests/replication/_base.py
@@ -65,7 +65,7 @@ class BaseStreamTestCase(unittest.HomeserverTestCase):
 
         # Since we use sqlite in memory databases we need to make sure the
         # databases objects are the same.
-        self.worker_hs.get_datastore().db = hs.get_datastore().db
+        self.worker_hs.get_datastore().db_pool = hs.get_datastore().db_pool
 
         self.test_handler = self._build_replication_data_handler()
         self.worker_hs.replication_data_handler = self.test_handler
@@ -198,7 +198,7 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         self.streamer = self.hs.get_replication_streamer()
 
         store = self.hs.get_datastore()
-        self.database = store.db
+        self.database_pool = store.db_pool
 
         self.reactor.lookups["testserv"] = "1.2.3.4"
 
@@ -254,7 +254,7 @@ class BaseMultiWorkerStreamTestCase(unittest.HomeserverTestCase):
         )
 
         store = worker_hs.get_datastore()
-        store.db._db_pool = self.database._db_pool
+        store.db_pool._db_pool = self.database_pool._db_pool
 
         repl_handler = ReplicationCommandHandler(worker_hs)
         client = ClientReplicationStreamProtocol(
diff --git a/tests/rest/admin/test_room.py b/tests/rest/admin/test_room.py
index cec1cf928f..408c568a27 100644
--- a/tests/rest/admin/test_room.py
+++ b/tests/rest/admin/test_room.py
@@ -566,7 +566,7 @@ class DeleteRoomTestCase(unittest.HomeserverTestCase):
             "state_groups_state",
         ):
             count = self.get_success(
-                self.store.db.simple_select_one_onecol(
+                self.store.db_pool.simple_select_one_onecol(
                     table=table,
                     keyvalues={"room_id": room_id},
                     retcol="COUNT(*)",
@@ -667,7 +667,7 @@ class PurgeRoomTestCase(unittest.HomeserverTestCase):
             "state_groups_state",
         ):
             count = self.get_success(
-                self.store.db.simple_select_one_onecol(
+                self.store.db_pool.simple_select_one_onecol(
                     table=table,
                     keyvalues={"room_id": room_id},
                     retcol="COUNT(*)",
diff --git a/tests/storage/test__base.py b/tests/storage/test__base.py
index 5a50e4fdd4..319e2c2325 100644
--- a/tests/storage/test__base.py
+++ b/tests/storage/test__base.py
@@ -323,7 +323,7 @@ class UpsertManyTests(unittest.HomeserverTestCase):
 
         self.table_name = "table_" + hs.get_secrets().token_hex(6)
         self.get_success(
-            self.storage.db.runInteraction(
+            self.storage.db_pool.runInteraction(
                 "create",
                 lambda x, *a: x.execute(*a),
                 "CREATE TABLE %s (id INTEGER, username TEXT, value TEXT)"
@@ -331,7 +331,7 @@ class UpsertManyTests(unittest.HomeserverTestCase):
             )
         )
         self.get_success(
-            self.storage.db.runInteraction(
+            self.storage.db_pool.runInteraction(
                 "index",
                 lambda x, *a: x.execute(*a),
                 "CREATE UNIQUE INDEX %sindex ON %s(id, username)"
@@ -354,9 +354,9 @@ class UpsertManyTests(unittest.HomeserverTestCase):
         value_values = [["hello"], ["there"]]
 
         self.get_success(
-            self.storage.db.runInteraction(
+            self.storage.db_pool.runInteraction(
                 "test",
-                self.storage.db.simple_upsert_many_txn,
+                self.storage.db_pool.simple_upsert_many_txn,
                 self.table_name,
                 key_names,
                 key_values,
@@ -367,7 +367,7 @@ class UpsertManyTests(unittest.HomeserverTestCase):
 
         # Check results are what we expect
         res = self.get_success(
-            self.storage.db.simple_select_list(
+            self.storage.db_pool.simple_select_list(
                 self.table_name, None, ["id, username, value"]
             )
         )
@@ -381,9 +381,9 @@ class UpsertManyTests(unittest.HomeserverTestCase):
         value_values = [["bleb"]]
 
         self.get_success(
-            self.storage.db.runInteraction(
+            self.storage.db_pool.runInteraction(
                 "test",
-                self.storage.db.simple_upsert_many_txn,
+                self.storage.db_pool.simple_upsert_many_txn,
                 self.table_name,
                 key_names,
                 key_values,
@@ -394,7 +394,7 @@ class UpsertManyTests(unittest.HomeserverTestCase):
 
         # Check results are what we expect
         res = self.get_success(
-            self.storage.db.simple_select_list(
+            self.storage.db_pool.simple_select_list(
                 self.table_name, None, ["id, username, value"]
             )
         )
diff --git a/tests/storage/test_appservice.py b/tests/storage/test_appservice.py
index ef296e7dab..1b516b7976 100644
--- a/tests/storage/test_appservice.py
+++ b/tests/storage/test_appservice.py
@@ -24,11 +24,11 @@ from twisted.internet import defer
 
 from synapse.appservice import ApplicationService, ApplicationServiceState
 from synapse.config._base import ConfigError
-from synapse.storage.data_stores.main.appservice import (
+from synapse.storage.database import DatabasePool, make_conn
+from synapse.storage.databases.main.appservice import (
     ApplicationServiceStore,
     ApplicationServiceTransactionStore,
 )
-from synapse.storage.database import Database, make_conn
 
 from tests import unittest
 from tests.utils import setup_test_homeserver
@@ -391,7 +391,7 @@ class ApplicationServiceTransactionStoreTestCase(unittest.TestCase):
 
 # required for ApplicationServiceTransactionStoreTestCase tests
 class TestTransactionStore(ApplicationServiceTransactionStore, ApplicationServiceStore):
-    def __init__(self, database: Database, db_conn, hs):
+    def __init__(self, database: DatabasePool, db_conn, hs):
         super(TestTransactionStore, self).__init__(database, db_conn, hs)
 
 
diff --git a/tests/storage/test_background_update.py b/tests/storage/test_background_update.py
index 940b166129..2efbc97c2e 100644
--- a/tests/storage/test_background_update.py
+++ b/tests/storage/test_background_update.py
@@ -9,7 +9,9 @@ from tests import unittest
 
 class BackgroundUpdateTestCase(unittest.HomeserverTestCase):
     def prepare(self, reactor, clock, homeserver):
-        self.updates = self.hs.get_datastore().db.updates  # type: BackgroundUpdater
+        self.updates = (
+            self.hs.get_datastore().db_pool.updates
+        )  # type: BackgroundUpdater
         # the base test class should have run the real bg updates for us
         self.assertTrue(
             self.get_success(self.updates.has_completed_background_updates())
@@ -29,7 +31,7 @@ class BackgroundUpdateTestCase(unittest.HomeserverTestCase):
 
         store = self.hs.get_datastore()
         self.get_success(
-            store.db.simple_insert(
+            store.db_pool.simple_insert(
                 "background_updates",
                 values={"update_name": "test_update", "progress_json": '{"my_key": 1}'},
             )
@@ -40,7 +42,7 @@ class BackgroundUpdateTestCase(unittest.HomeserverTestCase):
         def update(progress, count):
             yield self.clock.sleep((count * duration_ms) / 1000)
             progress = {"my_key": progress["my_key"] + 1}
-            yield store.db.runInteraction(
+            yield store.db_pool.runInteraction(
                 "update_progress",
                 self.updates._background_update_progress_txn,
                 "test_update",
diff --git a/tests/storage/test_base.py b/tests/storage/test_base.py
index b589506c60..efcaeef1e7 100644
--- a/tests/storage/test_base.py
+++ b/tests/storage/test_base.py
@@ -21,7 +21,7 @@ from mock import Mock
 from twisted.internet import defer
 
 from synapse.storage._base import SQLBaseStore
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.engines import create_engine
 
 from tests import unittest
@@ -57,7 +57,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
         fake_engine = Mock(wraps=engine)
         fake_engine.can_native_upsert = False
 
-        db = Database(Mock(), Mock(config=sqlite_config), fake_engine)
+        db = DatabasePool(Mock(), Mock(config=sqlite_config), fake_engine)
         db._db_pool = self.db_pool
 
         self.datastore = SQLBaseStore(db, None, hs)
@@ -66,7 +66,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
     def test_insert_1col(self):
         self.mock_txn.rowcount = 1
 
-        yield self.datastore.db.simple_insert(
+        yield self.datastore.db_pool.simple_insert(
             table="tablename", values={"columname": "Value"}
         )
 
@@ -78,7 +78,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
     def test_insert_3cols(self):
         self.mock_txn.rowcount = 1
 
-        yield self.datastore.db.simple_insert(
+        yield self.datastore.db_pool.simple_insert(
             table="tablename",
             # Use OrderedDict() so we can assert on the SQL generated
             values=OrderedDict([("colA", 1), ("colB", 2), ("colC", 3)]),
@@ -93,7 +93,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
         self.mock_txn.rowcount = 1
         self.mock_txn.__iter__ = Mock(return_value=iter([("Value",)]))
 
-        value = yield self.datastore.db.simple_select_one_onecol(
+        value = yield self.datastore.db_pool.simple_select_one_onecol(
             table="tablename", keyvalues={"keycol": "TheKey"}, retcol="retcol"
         )
 
@@ -107,7 +107,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
         self.mock_txn.rowcount = 1
         self.mock_txn.fetchone.return_value = (1, 2, 3)
 
-        ret = yield self.datastore.db.simple_select_one(
+        ret = yield self.datastore.db_pool.simple_select_one(
             table="tablename",
             keyvalues={"keycol": "TheKey"},
             retcols=["colA", "colB", "colC"],
@@ -123,7 +123,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
         self.mock_txn.rowcount = 0
         self.mock_txn.fetchone.return_value = None
 
-        ret = yield self.datastore.db.simple_select_one(
+        ret = yield self.datastore.db_pool.simple_select_one(
             table="tablename",
             keyvalues={"keycol": "Not here"},
             retcols=["colA"],
@@ -138,7 +138,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
         self.mock_txn.__iter__ = Mock(return_value=iter([(1,), (2,), (3,)]))
         self.mock_txn.description = (("colA", None, None, None, None, None, None),)
 
-        ret = yield self.datastore.db.simple_select_list(
+        ret = yield self.datastore.db_pool.simple_select_list(
             table="tablename", keyvalues={"keycol": "A set"}, retcols=["colA"]
         )
 
@@ -151,7 +151,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
     def test_update_one_1col(self):
         self.mock_txn.rowcount = 1
 
-        yield self.datastore.db.simple_update_one(
+        yield self.datastore.db_pool.simple_update_one(
             table="tablename",
             keyvalues={"keycol": "TheKey"},
             updatevalues={"columnname": "New Value"},
@@ -166,7 +166,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
     def test_update_one_4cols(self):
         self.mock_txn.rowcount = 1
 
-        yield self.datastore.db.simple_update_one(
+        yield self.datastore.db_pool.simple_update_one(
             table="tablename",
             keyvalues=OrderedDict([("colA", 1), ("colB", 2)]),
             updatevalues=OrderedDict([("colC", 3), ("colD", 4)]),
@@ -181,7 +181,7 @@ class SQLBaseStoreTestCase(unittest.TestCase):
     def test_delete_one(self):
         self.mock_txn.rowcount = 1
 
-        yield self.datastore.db.simple_delete_one(
+        yield self.datastore.db_pool.simple_delete_one(
             table="tablename", keyvalues={"keycol": "Go away"}
         )
 
diff --git a/tests/storage/test_cleanup_extrems.py b/tests/storage/test_cleanup_extrems.py
index 43425c969a..3fab5a5248 100644
--- a/tests/storage/test_cleanup_extrems.py
+++ b/tests/storage/test_cleanup_extrems.py
@@ -47,12 +47,12 @@ class CleanupExtremBackgroundUpdateStoreTestCase(HomeserverTestCase):
         """
         # Make sure we don't clash with in progress updates.
         self.assertTrue(
-            self.store.db.updates._all_done, "Background updates are still ongoing"
+            self.store.db_pool.updates._all_done, "Background updates are still ongoing"
         )
 
         schema_path = os.path.join(
             prepare_database.dir_path,
-            "data_stores",
+            "databases",
             "main",
             "schema",
             "delta",
@@ -64,19 +64,19 @@ class CleanupExtremBackgroundUpdateStoreTestCase(HomeserverTestCase):
             prepare_database.executescript(txn, schema_path)
 
         self.get_success(
-            self.store.db.runInteraction(
+            self.store.db_pool.runInteraction(
                 "test_delete_forward_extremities", run_delta_file
             )
         )
 
         # Ugh, have to reset this flag
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
 
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
     def test_soft_failed_extremities_handled_correctly(self):
diff --git a/tests/storage/test_client_ips.py b/tests/storage/test_client_ips.py
index 3b483bc7f0..224ea6fd79 100644
--- a/tests/storage/test_client_ips.py
+++ b/tests/storage/test_client_ips.py
@@ -86,7 +86,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         self.pump(0)
 
         result = self.get_success(
-            self.store.db.simple_select_list(
+            self.store.db_pool.simple_select_list(
                 table="user_ips",
                 keyvalues={"user_id": user_id},
                 retcols=["access_token", "ip", "user_agent", "device_id", "last_seen"],
@@ -117,7 +117,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         self.pump(0)
 
         result = self.get_success(
-            self.store.db.simple_select_list(
+            self.store.db_pool.simple_select_list(
                 table="user_ips",
                 keyvalues={"user_id": user_id},
                 retcols=["access_token", "ip", "user_agent", "device_id", "last_seen"],
@@ -204,10 +204,10 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
     def test_devices_last_seen_bg_update(self):
         # First make sure we have completed all updates.
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         user_id = "@user:id"
@@ -225,7 +225,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
 
         # But clear the associated entry in devices table
         self.get_success(
-            self.store.db.simple_update(
+            self.store.db_pool.simple_update(
                 table="devices",
                 keyvalues={"user_id": user_id, "device_id": device_id},
                 updatevalues={"last_seen": None, "ip": None, "user_agent": None},
@@ -252,7 +252,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
 
         # Register the background update to run again.
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 table="background_updates",
                 values={
                     "update_name": "devices_last_seen",
@@ -263,14 +263,14 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
         )
 
         # ... and tell the DataStore that it hasn't finished all updates yet
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
 
         # Now let's actually drive the updates to completion
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         # We should now get the correct result again
@@ -293,10 +293,10 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
     def test_old_user_ips_pruned(self):
         # First make sure we have completed all updates.
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         user_id = "@user:id"
@@ -315,7 +315,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
 
         # We should see that in the DB
         result = self.get_success(
-            self.store.db.simple_select_list(
+            self.store.db_pool.simple_select_list(
                 table="user_ips",
                 keyvalues={"user_id": user_id},
                 retcols=["access_token", "ip", "user_agent", "device_id", "last_seen"],
@@ -341,7 +341,7 @@ class ClientIpStoreTestCase(unittest.HomeserverTestCase):
 
         # We should get no results.
         result = self.get_success(
-            self.store.db.simple_select_list(
+            self.store.db_pool.simple_select_list(
                 table="user_ips",
                 keyvalues={"user_id": user_id},
                 retcols=["access_token", "ip", "user_agent", "device_id", "last_seen"],
diff --git a/tests/storage/test_event_federation.py b/tests/storage/test_event_federation.py
index 3aeec0dc0f..d4c3b867e3 100644
--- a/tests/storage/test_event_federation.py
+++ b/tests/storage/test_event_federation.py
@@ -56,7 +56,9 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
             )
 
         for i in range(0, 20):
-            self.get_success(self.store.db.runInteraction("insert", insert_event, i))
+            self.get_success(
+                self.store.db_pool.runInteraction("insert", insert_event, i)
+            )
 
         # this should get the last ten
         r = self.get_success(self.store.get_prev_events_for_room(room_id))
@@ -81,13 +83,13 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
 
         for i in range(0, 20):
             self.get_success(
-                self.store.db.runInteraction("insert", insert_event, i, room1)
+                self.store.db_pool.runInteraction("insert", insert_event, i, room1)
             )
             self.get_success(
-                self.store.db.runInteraction("insert", insert_event, i, room2)
+                self.store.db_pool.runInteraction("insert", insert_event, i, room2)
             )
             self.get_success(
-                self.store.db.runInteraction("insert", insert_event, i, room3)
+                self.store.db_pool.runInteraction("insert", insert_event, i, room3)
             )
 
         # Test simple case
@@ -164,7 +166,7 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
 
             depth = depth_map[event_id]
 
-            self.store.db.simple_insert_txn(
+            self.store.db_pool.simple_insert_txn(
                 txn,
                 table="events",
                 values={
@@ -179,7 +181,7 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
                 },
             )
 
-            self.store.db.simple_insert_many_txn(
+            self.store.db_pool.simple_insert_many_txn(
                 txn,
                 table="event_auth",
                 values=[
@@ -192,7 +194,7 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
         for event_id in auth_graph:
             next_stream_ordering += 1
             self.get_success(
-                self.store.db.runInteraction(
+                self.store.db_pool.runInteraction(
                     "insert", insert_event, event_id, next_stream_ordering
                 )
             )
diff --git a/tests/storage/test_event_push_actions.py b/tests/storage/test_event_push_actions.py
index 2b1580feeb..857db071d4 100644
--- a/tests/storage/test_event_push_actions.py
+++ b/tests/storage/test_event_push_actions.py
@@ -60,7 +60,7 @@ class EventPushActionsStoreTestCase(tests.unittest.TestCase):
 
         @defer.inlineCallbacks
         def _assert_counts(noitf_count, highlight_count):
-            counts = yield self.store.db.runInteraction(
+            counts = yield self.store.db_pool.runInteraction(
                 "", self.store._get_unread_counts_by_pos_txn, room_id, user_id, 0
             )
             self.assertEquals(
@@ -81,7 +81,7 @@ class EventPushActionsStoreTestCase(tests.unittest.TestCase):
                     event.event_id, {user_id: action}
                 )
             )
-            yield self.store.db.runInteraction(
+            yield self.store.db_pool.runInteraction(
                 "",
                 self.persist_events_store._set_push_actions_for_event_and_users_txn,
                 [(event, None)],
@@ -89,12 +89,12 @@ class EventPushActionsStoreTestCase(tests.unittest.TestCase):
             )
 
         def _rotate(stream):
-            return self.store.db.runInteraction(
+            return self.store.db_pool.runInteraction(
                 "", self.store._rotate_notifs_before_txn, stream
             )
 
         def _mark_read(stream, depth):
-            return self.store.db.runInteraction(
+            return self.store.db_pool.runInteraction(
                 "",
                 self.store._remove_old_push_actions_before_txn,
                 room_id,
@@ -123,7 +123,7 @@ class EventPushActionsStoreTestCase(tests.unittest.TestCase):
         yield _inject_actions(6, PlAIN_NOTIF)
         yield _rotate(7)
 
-        yield self.store.db.simple_delete(
+        yield self.store.db_pool.simple_delete(
             table="event_push_actions", keyvalues={"1": 1}, desc=""
         )
 
@@ -142,7 +142,7 @@ class EventPushActionsStoreTestCase(tests.unittest.TestCase):
     @defer.inlineCallbacks
     def test_find_first_stream_ordering_after_ts(self):
         def add_event(so, ts):
-            return self.store.db.simple_insert(
+            return self.store.db_pool.simple_insert(
                 "events",
                 {
                     "stream_ordering": so,
diff --git a/tests/storage/test_id_generators.py b/tests/storage/test_id_generators.py
index 55e9ecf264..e845410dae 100644
--- a/tests/storage/test_id_generators.py
+++ b/tests/storage/test_id_generators.py
@@ -14,7 +14,7 @@
 # limitations under the License.
 
 
-from synapse.storage.database import Database
+from synapse.storage.database import DatabasePool
 from synapse.storage.util.id_generators import MultiWriterIdGenerator
 
 from tests.unittest import HomeserverTestCase
@@ -27,9 +27,9 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
 
     def prepare(self, reactor, clock, hs):
         self.store = hs.get_datastore()
-        self.db = self.store.db  # type: Database
+        self.db_pool = self.store.db_pool  # type: DatabasePool
 
-        self.get_success(self.db.runInteraction("_setup_db", self._setup_db))
+        self.get_success(self.db_pool.runInteraction("_setup_db", self._setup_db))
 
     def _setup_db(self, txn):
         txn.execute("CREATE SEQUENCE foobar_seq")
@@ -47,7 +47,7 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
         def _create(conn):
             return MultiWriterIdGenerator(
                 conn,
-                self.db,
+                self.db_pool,
                 instance_name=instance_name,
                 table="foobar",
                 instance_column="instance_name",
@@ -55,7 +55,7 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
                 sequence_name="foobar_seq",
             )
 
-        return self.get_success(self.db.runWithConnection(_create))
+        return self.get_success(self.db_pool.runWithConnection(_create))
 
     def _insert_rows(self, instance_name: str, number: int):
         def _insert(txn):
@@ -65,7 +65,7 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
                     (instance_name,),
                 )
 
-        self.get_success(self.db.runInteraction("test_single_instance", _insert))
+        self.get_success(self.db_pool.runInteraction("test_single_instance", _insert))
 
     def test_empty(self):
         """Test an ID generator against an empty database gives sensible
@@ -178,7 +178,7 @@ class MultiWriterIdGeneratorTestCase(HomeserverTestCase):
             self.assertEqual(id_gen.get_positions(), {"master": 7})
             self.assertEqual(id_gen.get_current_token("master"), 7)
 
-        self.get_success(self.db.runInteraction("test", _get_next_txn))
+        self.get_success(self.db_pool.runInteraction("test", _get_next_txn))
 
         self.assertEqual(id_gen.get_positions(), {"master": 8})
         self.assertEqual(id_gen.get_current_token("master"), 8)
diff --git a/tests/storage/test_monthly_active_users.py b/tests/storage/test_monthly_active_users.py
index 9c04e92577..259f2215f1 100644
--- a/tests/storage/test_monthly_active_users.py
+++ b/tests/storage/test_monthly_active_users.py
@@ -78,7 +78,7 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
         # XXX why are we doing this here? this function is only run at startup
         # so it is odd to re-run it here.
         self.get_success(
-            self.store.db.runInteraction(
+            self.store.db_pool.runInteraction(
                 "initialise", self.store._initialise_reserved_users, threepids
             )
         )
@@ -204,7 +204,7 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
                     self.store.user_add_threepid(user, "email", email, now, now)
                 )
 
-        d = self.store.db.runInteraction(
+        d = self.store.db_pool.runInteraction(
             "initialise", self.store._initialise_reserved_users, threepids
         )
         self.get_success(d)
@@ -280,7 +280,7 @@ class MonthlyActiveUsersTestCase(unittest.HomeserverTestCase):
         ]
 
         self.hs.config.mau_limits_reserved_threepids = threepids
-        d = self.store.db.runInteraction(
+        d = self.store.db_pool.runInteraction(
             "initialise", self.store._initialise_reserved_users, threepids
         )
         self.get_success(d)
diff --git a/tests/storage/test_redaction.py b/tests/storage/test_redaction.py
index 0f0e1cd09b..41511d479f 100644
--- a/tests/storage/test_redaction.py
+++ b/tests/storage/test_redaction.py
@@ -343,7 +343,7 @@ class RedactionTestCase(unittest.HomeserverTestCase):
         )
 
         event_json = self.get_success(
-            self.store.db.simple_select_one_onecol(
+            self.store.db_pool.simple_select_one_onecol(
                 table="event_json",
                 keyvalues={"event_id": msg_event.event_id},
                 retcol="json",
@@ -361,7 +361,7 @@ class RedactionTestCase(unittest.HomeserverTestCase):
         self.reactor.advance(60 * 60 * 2)
 
         event_json = self.get_success(
-            self.store.db.simple_select_one_onecol(
+            self.store.db_pool.simple_select_one_onecol(
                 table="event_json",
                 keyvalues={"event_id": msg_event.event_id},
                 retcol="json",
diff --git a/tests/storage/test_roommember.py b/tests/storage/test_roommember.py
index f282921538..17c9da4838 100644
--- a/tests/storage/test_roommember.py
+++ b/tests/storage/test_roommember.py
@@ -179,10 +179,10 @@ class CurrentStateMembershipUpdateTestCase(unittest.HomeserverTestCase):
     def test_can_rerun_update(self):
         # First make sure we have completed all updates.
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
 
         # Now let's create a room, which will insert a membership
@@ -192,7 +192,7 @@ class CurrentStateMembershipUpdateTestCase(unittest.HomeserverTestCase):
 
         # Register the background update to run again.
         self.get_success(
-            self.store.db.simple_insert(
+            self.store.db_pool.simple_insert(
                 table="background_updates",
                 values={
                     "update_name": "current_state_events_membership",
@@ -203,12 +203,12 @@ class CurrentStateMembershipUpdateTestCase(unittest.HomeserverTestCase):
         )
 
         # ... and tell the DataStore that it hasn't finished all updates yet
-        self.store.db.updates._all_done = False
+        self.store.db_pool.updates._all_done = False
 
         # Now let's actually drive the updates to completion
         while not self.get_success(
-            self.store.db.updates.has_completed_background_updates()
+            self.store.db_pool.updates.has_completed_background_updates()
         ):
             self.get_success(
-                self.store.db.updates.do_next_background_update(100), by=0.1
+                self.store.db_pool.updates.do_next_background_update(100), by=0.1
             )
diff --git a/tests/unittest.py b/tests/unittest.py
index 68d2586efd..2152c693f2 100644
--- a/tests/unittest.py
+++ b/tests/unittest.py
@@ -422,8 +422,8 @@ class HomeserverTestCase(TestCase):
 
         async def run_bg_updates():
             with LoggingContext("run_bg_updates", request="run_bg_updates-1"):
-                while not await stor.db.updates.has_completed_background_updates():
-                    await stor.db.updates.do_next_background_update(1)
+                while not await stor.db_pool.updates.has_completed_background_updates():
+                    await stor.db_pool.updates.do_next_background_update(1)
 
         hs = setup_test_homeserver(self.addCleanup, *args, **kwargs)
         stor = hs.get_datastore()
@@ -571,7 +571,7 @@ class HomeserverTestCase(TestCase):
         Add the given event as an extremity to the room.
         """
         self.get_success(
-            self.hs.get_datastore().db.simple_insert(
+            self.hs.get_datastore().db_pool.simple_insert(
                 table="event_forward_extremities",
                 values={"room_id": room_id, "event_id": event_id},
                 desc="test_add_extremity",
diff --git a/tox.ini b/tox.ini
index 2b1db0f7f7..9a052c1e33 100644
--- a/tox.ini
+++ b/tox.ini
@@ -204,7 +204,7 @@ commands = mypy \
             synapse/rest \
             synapse/server_notices \
             synapse/spam_checker_api \
-            synapse/storage/data_stores/main/ui_auth.py \
+            synapse/storage/databases/main/ui_auth.py \
             synapse/storage/database.py \
             synapse/storage/engines \
             synapse/storage/state.py \