Merge remote-tracking branch 'origin/develop' into hawkowl/cache-config-without-synctl

93 files changed, 1995 insertions, 3031 deletions

diff --git a/synapse/__init__.py b/synapse/__init__.py
index 9d285fca38..3406ce634f 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -36,7 +36,7 @@ try:
 except ImportError:
     pass
 
-__version__ = "1.10.0"
+__version__ = "1.11.0"
 
 if bool(os.environ.get("SYNAPSE_TEST_PATCH_LOG_CONTEXTS", False)):
     # We import here so that we don't have to install a bunch of deps when
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index ff88f282cd..fc172ba854 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import logging
+from typing import Optional
 
 from six import itervalues
 
@@ -35,6 +36,7 @@ from synapse.api.errors import (
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.config.server import is_threepid_reserved
+from synapse.events import EventBase
 from synapse.types import StateMap, UserID
 from synapse.util.caches import register_cache
 from synapse.util.caches.lrucache import LruCache
@@ -92,20 +94,34 @@ class Auth(object):
         )
 
     @defer.inlineCallbacks
-    def check_joined_room(self, room_id, user_id, current_state=None):
-        """Check if the user is currently joined in the room
+    def check_user_in_room(
+        self,
+        room_id: str,
+        user_id: str,
+        current_state: Optional[StateMap[EventBase]] = None,
+        allow_departed_users: bool = False,
+    ):
+        """Check if the user is in the room, or was at some point.
         Args:
-            room_id(str): The room to check.
-            user_id(str): The user to check.
-            current_state(dict): Optional map of the current state of the room.
+            room_id: The room to check.
+
+            user_id: The user to check.
+
+            current_state: Optional map of the current state of the room.
                 If provided then that map is used to check whether they are a
                 member of the room. Otherwise the current membership is
                 loaded from the database.
+
+            allow_departed_users: if True, accept users that were previously
+                members but have now departed.
+
         Raises:
-            AuthError if the user is not in the room.
+            AuthError if the user is/was not in the room.
         Returns:
-            A deferred membership event for the user if the user is in
-            the room.
+            Deferred[Optional[EventBase]]:
+                Membership event for the user if the user was in the
+                room. This will be the join event if they are currently joined to
+                the room. This will be the leave event if they have left the room.
         """
         if current_state:
             member = current_state.get((EventTypes.Member, user_id), None)
@@ -113,37 +129,19 @@ class Auth(object):
             member = yield self.state.get_current_state(
                 room_id=room_id, event_type=EventTypes.Member, state_key=user_id
             )
-
-        self._check_joined_room(member, user_id, room_id)
-        return member
-
-    @defer.inlineCallbacks
-    def check_user_was_in_room(self, room_id, user_id):
-        """Check if the user was in the room at some point.
-        Args:
-            room_id(str): The room to check.
-            user_id(str): The user to check.
-        Raises:
-            AuthError if the user was never in the room.
-        Returns:
-            A deferred membership event for the user if the user was in the
-            room. This will be the join event if they are currently joined to
-            the room. This will be the leave event if they have left the room.
-        """
-        member = yield self.state.get_current_state(
-            room_id=room_id, event_type=EventTypes.Member, state_key=user_id
-        )
         membership = member.membership if member else None
 
-        if membership not in (Membership.JOIN, Membership.LEAVE):
-            raise AuthError(403, "User %s not in room %s" % (user_id, room_id))
+        if membership == Membership.JOIN:
+            return member
 
-        if membership == Membership.LEAVE:
+        # XXX this looks totally bogus. Why do we not allow users who have been banned,
+        # or those who were members previously and have been re-invited?
+        if allow_departed_users and membership == Membership.LEAVE:
             forgot = yield self.store.did_forget(user_id, room_id)
-            if forgot:
-                raise AuthError(403, "User %s not in room %s" % (user_id, room_id))
+            if not forgot:
+                return member
 
-        return member
+        raise AuthError(403, "User %s not in room %s" % (user_id, room_id))
 
     @defer.inlineCallbacks
     def check_host_in_room(self, room_id, host):
@@ -151,12 +149,6 @@ class Auth(object):
             latest_event_ids = yield self.store.is_host_joined(room_id, host)
             return latest_event_ids
 
-    def _check_joined_room(self, member, user_id, room_id):
-        if not member or member.membership != Membership.JOIN:
-            raise AuthError(
-                403, "User %s not in room %s (%s)" % (user_id, room_id, repr(member))
-            )
-
     def can_federate(self, event, auth_events):
         creation_event = auth_events.get((EventTypes.Create, ""))
 
@@ -546,13 +538,13 @@ class Auth(object):
         return defer.succeed(auth_ids)
 
     @defer.inlineCallbacks
-    def check_can_change_room_list(self, room_id, user):
+    def check_can_change_room_list(self, room_id: str, user: UserID):
         """Check if the user is allowed to edit the room's entry in the
         published room list.
 
         Args:
-            room_id (str)
-            user (UserID)
+            room_id
+            user
         """
 
         is_admin = yield self.is_server_admin(user)
@@ -560,11 +552,11 @@ class Auth(object):
             return True
 
         user_id = user.to_string()
-        yield self.check_joined_room(room_id, user_id)
+        yield self.check_user_in_room(room_id, user_id)
 
         # We currently require the user is a "moderator" in the room. We do this
         # by checking if they would (theoretically) be able to change the
-        # m.room.aliases events
+        # m.room.canonical_alias events
         power_level_event = yield self.state.get_current_state(
             room_id, EventTypes.PowerLevels, ""
         )
@@ -574,7 +566,7 @@ class Auth(object):
             auth_events[(EventTypes.PowerLevels, "")] = power_level_event
 
         send_level = event_auth.get_send_level(
-            EventTypes.Aliases, "", power_level_event
+            EventTypes.CanonicalAlias, "", power_level_event
         )
         user_level = event_auth.get_user_power_level(user_id, auth_events)
 
@@ -633,10 +625,18 @@ class Auth(object):
             return query_params[0].decode("ascii")
 
     @defer.inlineCallbacks
-    def check_in_room_or_world_readable(self, room_id, user_id):
+    def check_user_in_room_or_world_readable(
+        self, room_id: str, user_id: str, allow_departed_users: bool = False
+    ):
         """Checks that the user is or was in the room or the room is world
         readable. If it isn't then an exception is raised.
 
+        Args:
+            room_id: room to check
+            user_id: user to check
+            allow_departed_users: if True, accept users that were previously
+                members but have now departed
+
         Returns:
             Deferred[tuple[str, str|None]]: Resolves to the current membership of
                 the user in the room and the membership event ID of the user. If
@@ -645,12 +645,14 @@ class Auth(object):
         """
 
         try:
-            # check_user_was_in_room will return the most recent membership
+            # check_user_in_room will return the most recent membership
             # event for the user if:
             #  * The user is a non-guest user, and was ever in the room
             #  * The user is a guest user, and has joined the room
             # else it will throw.
-            member_event = yield self.check_user_was_in_room(room_id, user_id)
+            member_event = yield self.check_user_in_room(
+                room_id, user_id, allow_departed_users=allow_departed_users
+            )
             return member_event.membership, member_event.event_id
         except AuthError:
             visibility = yield self.state.get_current_state(
@@ -662,7 +664,9 @@ class Auth(object):
             ):
                 return Membership.JOIN, None
             raise AuthError(
-                403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
+                403,
+                "User %s not in room %s, and room previews are disabled"
+                % (user_id, room_id),
             )
 
     @defer.inlineCallbacks
diff --git a/synapse/app/_base.py b/synapse/app/_base.py
index 0e8b467a3e..9ffd23c6df 100644
--- a/synapse/app/_base.py
+++ b/synapse/app/_base.py
@@ -141,7 +141,7 @@ def start_reactor(
 
 def quit_with_error(error_string):
     message_lines = error_string.split("\n")
-    line_length = max([len(l) for l in message_lines if len(l) < 80]) + 2
+    line_length = max(len(l) for l in message_lines if len(l) < 80) + 2
     sys.stderr.write("*" * line_length + "\n")
     for line in message_lines:
         sys.stderr.write(" %s\n" % (line.rstrip(),))
@@ -279,6 +279,15 @@ def start(hs, listeners=None):
 
         setup_sentry(hs)
         setup_sdnotify(hs)
+
+        # We now freeze all allocated objects in the hopes that (almost)
+        # everything currently allocated are things that will be used for the
+        # rest of time. Doing so means less work each GC (hopefully).
+        #
+        # This only works on Python 3.7
+        if sys.version_info >= (3, 7):
+            gc.collect()
+            gc.freeze()
     except Exception:
         traceback.print_exc(file=sys.stderr)
         reactor = hs.get_reactor()
diff --git a/synapse/app/appservice.py b/synapse/app/appservice.py
index 2217d4a4fb..add43147b3 100644
--- a/synapse/app/appservice.py
+++ b/synapse/app/appservice.py
@@ -13,161 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext, run_in_background
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.directory import DirectoryStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.server import HomeServer
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.appservice")
-
-
-class AppserviceSlaveStore(
-    DirectoryStore,
-    SlavedEventStore,
-    SlavedApplicationServiceStore,
-    SlavedRegistrationStore,
-):
-    pass
-
-
-class AppserviceServer(HomeServer):
-    DATASTORE_CLASS = AppserviceSlaveStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
-
-        logger.info("Synapse appservice now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return ASReplicationHandler(self)
 
+import sys
 
-class ASReplicationHandler(ReplicationClientHandler):
-    def __init__(self, hs):
-        super(ASReplicationHandler, self).__init__(hs.get_datastore())
-        self.appservice_handler = hs.get_application_service_handler()
-
-    async def on_rdata(self, stream_name, token, rows):
-        await super(ASReplicationHandler, self).on_rdata(stream_name, token, rows)
-
-        if stream_name == "events":
-            max_stream_id = self.store.get_room_max_stream_ordering()
-            run_in_background(self._notify_app_services, max_stream_id)
-
-    @defer.inlineCallbacks
-    def _notify_app_services(self, room_stream_id):
-        try:
-            yield self.appservice_handler.notify_interested_services(room_stream_id)
-        except Exception:
-            logger.exception("Error notifying application services of event")
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config("Synapse appservice", config_options)
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.appservice"
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    if config.notify_appservices:
-        sys.stderr.write(
-            "\nThe appservices must be disabled in the main synapse process"
-            "\nbefore they can be run in a separate worker."
-            "\nPlease add ``notify_appservices: false`` to the main config"
-            "\n"
-        )
-        sys.exit(1)
-
-    # Force the pushers to start since they will be disabled in the main config
-    config.notify_appservices = True
-
-    ps = AppserviceServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ps, config, use_worker_options=True)
-
-    ps.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ps, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-appservice", config)
-
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/client_reader.py b/synapse/app/client_reader.py
index 7fa91a3b11..add43147b3 100644
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@@ -13,195 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.http.server import JsonResource
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import BaseSlavedStore
-from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
-from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
-from synapse.replication.slave.storage.devices import SlavedDeviceStore
-from synapse.replication.slave.storage.directory import DirectoryStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.groups import SlavedGroupServerStore
-from synapse.replication.slave.storage.keys import SlavedKeyStore
-from synapse.replication.slave.storage.profile import SlavedProfileStore
-from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
-from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.slave.storage.room import RoomStore
-from synapse.replication.slave.storage.transactions import SlavedTransactionStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.rest.client.v1.login import LoginRestServlet
-from synapse.rest.client.v1.push_rule import PushRuleRestServlet
-from synapse.rest.client.v1.room import (
-    JoinedRoomMemberListRestServlet,
-    PublicRoomListRestServlet,
-    RoomEventContextServlet,
-    RoomMemberListRestServlet,
-    RoomMessageListRestServlet,
-    RoomStateRestServlet,
-)
-from synapse.rest.client.v1.voip import VoipRestServlet
-from synapse.rest.client.v2_alpha import groups
-from synapse.rest.client.v2_alpha.account import ThreepidRestServlet
-from synapse.rest.client.v2_alpha.keys import KeyChangesServlet, KeyQueryServlet
-from synapse.rest.client.v2_alpha.register import RegisterRestServlet
-from synapse.rest.client.versions import VersionsRestServlet
-from synapse.server import HomeServer
-from synapse.storage.data_stores.main.monthly_active_users import (
-    MonthlyActiveUsersWorkerStore,
-)
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.client_reader")
-
-
-class ClientReaderSlavedStore(
-    SlavedDeviceInboxStore,
-    SlavedDeviceStore,
-    SlavedReceiptsStore,
-    SlavedPushRuleStore,
-    SlavedGroupServerStore,
-    SlavedAccountDataStore,
-    SlavedEventStore,
-    SlavedKeyStore,
-    RoomStore,
-    DirectoryStore,
-    SlavedApplicationServiceStore,
-    SlavedRegistrationStore,
-    SlavedTransactionStore,
-    SlavedProfileStore,
-    SlavedClientIpStore,
-    MonthlyActiveUsersWorkerStore,
-    BaseSlavedStore,
-):
-    pass
-
-
-class ClientReaderServer(HomeServer):
-    DATASTORE_CLASS = ClientReaderSlavedStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-                elif name == "client":
-                    resource = JsonResource(self, canonical_json=False)
-
-                    PublicRoomListRestServlet(self).register(resource)
-                    RoomMemberListRestServlet(self).register(resource)
-                    JoinedRoomMemberListRestServlet(self).register(resource)
-                    RoomStateRestServlet(self).register(resource)
-                    RoomEventContextServlet(self).register(resource)
-                    RoomMessageListRestServlet(self).register(resource)
-                    RegisterRestServlet(self).register(resource)
-                    LoginRestServlet(self).register(resource)
-                    ThreepidRestServlet(self).register(resource)
-                    KeyQueryServlet(self).register(resource)
-                    KeyChangesServlet(self).register(resource)
-                    VoipRestServlet(self).register(resource)
-                    PushRuleRestServlet(self).register(resource)
-                    VersionsRestServlet(self).register(resource)
-
-                    groups.register_servlets(self, resource)
-
-                    resources.update({"/_matrix/client": resource})
-
-        root_resource = create_resource_tree(resources, NoResource())
 
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
-
-        logger.info("Synapse client reader now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return ReplicationClientHandler(self.get_datastore())
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config("Synapse client reader", config_options)
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.client_reader"
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    ss = ClientReaderServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-client-reader", config)
+import sys
 
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/event_creator.py b/synapse/app/event_creator.py
index 58e5b354f6..e9c098c4e7 100644
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@@ -13,191 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.http.server import JsonResource
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import BaseSlavedStore
-from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
-from synapse.replication.slave.storage.devices import SlavedDeviceStore
-from synapse.replication.slave.storage.directory import DirectoryStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.profile import SlavedProfileStore
-from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
-from synapse.replication.slave.storage.pushers import SlavedPusherStore
-from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.slave.storage.room import RoomStore
-from synapse.replication.slave.storage.transactions import SlavedTransactionStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.rest.client.v1.profile import (
-    ProfileAvatarURLRestServlet,
-    ProfileDisplaynameRestServlet,
-    ProfileRestServlet,
-)
-from synapse.rest.client.v1.room import (
-    JoinRoomAliasServlet,
-    RoomMembershipRestServlet,
-    RoomSendEventRestServlet,
-    RoomStateEventRestServlet,
-)
-from synapse.server import HomeServer
-from synapse.storage.data_stores.main.monthly_active_users import (
-    MonthlyActiveUsersWorkerStore,
-)
-from synapse.storage.data_stores.main.user_directory import UserDirectoryStore
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.event_creator")
-
-
-class EventCreatorSlavedStore(
-    # FIXME(#3714): We need to add UserDirectoryStore as we write directly
-    # rather than going via the correct worker.
-    UserDirectoryStore,
-    DirectoryStore,
-    SlavedTransactionStore,
-    SlavedProfileStore,
-    SlavedAccountDataStore,
-    SlavedPusherStore,
-    SlavedReceiptsStore,
-    SlavedPushRuleStore,
-    SlavedDeviceStore,
-    SlavedClientIpStore,
-    SlavedApplicationServiceStore,
-    SlavedEventStore,
-    SlavedRegistrationStore,
-    RoomStore,
-    MonthlyActiveUsersWorkerStore,
-    BaseSlavedStore,
-):
-    pass
-
-
-class EventCreatorServer(HomeServer):
-    DATASTORE_CLASS = EventCreatorSlavedStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-                elif name == "client":
-                    resource = JsonResource(self, canonical_json=False)
-                    RoomSendEventRestServlet(self).register(resource)
-                    RoomMembershipRestServlet(self).register(resource)
-                    RoomStateEventRestServlet(self).register(resource)
-                    JoinRoomAliasServlet(self).register(resource)
-                    ProfileAvatarURLRestServlet(self).register(resource)
-                    ProfileDisplaynameRestServlet(self).register(resource)
-                    ProfileRestServlet(self).register(resource)
-                    resources.update(
-                        {
-                            "/_matrix/client/r0": resource,
-                            "/_matrix/client/unstable": resource,
-                            "/_matrix/client/v2_alpha": resource,
-                            "/_matrix/client/api/v1": resource,
-                        }
-                    )
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
-
-        logger.info("Synapse event creator now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
 
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return ReplicationClientHandler(self.get_datastore())
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config("Synapse event creator", config_options)
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.event_creator"
-
-    assert config.worker_replication_http_port is not None
-
-    # This should only be done on the user directory worker or the master
-    config.update_user_directory = False
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    ss = EventCreatorServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-event-creator", config)
+import sys
 
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/federation_reader.py b/synapse/app/federation_reader.py
index d055d11b23..add43147b3 100644
--- a/synapse/app/federation_reader.py
+++ b/synapse/app/federation_reader.py
@@ -13,177 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.api.urls import FEDERATION_PREFIX, SERVER_KEY_V2_PREFIX
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.federation.transport.server import TransportLayerServer
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import BaseSlavedStore
-from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.devices import SlavedDeviceStore
-from synapse.replication.slave.storage.directory import DirectoryStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.groups import SlavedGroupServerStore
-from synapse.replication.slave.storage.keys import SlavedKeyStore
-from synapse.replication.slave.storage.profile import SlavedProfileStore
-from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
-from synapse.replication.slave.storage.pushers import SlavedPusherStore
-from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.slave.storage.room import RoomStore
-from synapse.replication.slave.storage.transactions import SlavedTransactionStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.rest.key.v2 import KeyApiV2Resource
-from synapse.server import HomeServer
-from synapse.storage.data_stores.main.monthly_active_users import (
-    MonthlyActiveUsersWorkerStore,
-)
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.federation_reader")
-
-
-class FederationReaderSlavedStore(
-    SlavedAccountDataStore,
-    SlavedProfileStore,
-    SlavedApplicationServiceStore,
-    SlavedPusherStore,
-    SlavedPushRuleStore,
-    SlavedReceiptsStore,
-    SlavedEventStore,
-    SlavedKeyStore,
-    SlavedRegistrationStore,
-    SlavedGroupServerStore,
-    SlavedDeviceStore,
-    RoomStore,
-    DirectoryStore,
-    SlavedTransactionStore,
-    MonthlyActiveUsersWorkerStore,
-    BaseSlavedStore,
-):
-    pass
-
-
-class FederationReaderServer(HomeServer):
-    DATASTORE_CLASS = FederationReaderSlavedStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-                elif name == "federation":
-                    resources.update({FEDERATION_PREFIX: TransportLayerServer(self)})
-                if name == "openid" and "federation" not in res["names"]:
-                    # Only load the openid resource separately if federation resource
-                    # is not specified since federation resource includes openid
-                    # resource.
-                    resources.update(
-                        {
-                            FEDERATION_PREFIX: TransportLayerServer(
-                                self, servlet_groups=["openid"]
-                            )
-                        }
-                    )
-
-                if name in ["keys", "federation"]:
-                    resources[SERVER_KEY_V2_PREFIX] = KeyApiV2Resource(self)
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-            reactor=self.get_reactor(),
-        )
 
-        logger.info("Synapse federation reader now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return ReplicationClientHandler(self.get_datastore())
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config(
-            "Synapse federation reader", config_options
-        )
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.federation_reader"
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    ss = FederationReaderServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-federation-reader", config)
+import sys
 
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py
index 63a91f1177..add43147b3 100644
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@@ -13,308 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.federation import send_queue
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext, run_in_background
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
-from synapse.replication.slave.storage.devices import SlavedDeviceStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.presence import SlavedPresenceStore
-from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.slave.storage.transactions import SlavedTransactionStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.replication.tcp.streams._base import (
-    DeviceListsStream,
-    ReceiptsStream,
-    ToDeviceStream,
-)
-from synapse.server import HomeServer
-from synapse.storage.database import Database
-from synapse.types import ReadReceipt
-from synapse.util.async_helpers import Linearizer
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.federation_sender")
-
-
-class FederationSenderSlaveStore(
-    SlavedDeviceInboxStore,
-    SlavedTransactionStore,
-    SlavedReceiptsStore,
-    SlavedEventStore,
-    SlavedRegistrationStore,
-    SlavedDeviceStore,
-    SlavedPresenceStore,
-):
-    def __init__(self, database: Database, db_conn, hs):
-        super(FederationSenderSlaveStore, self).__init__(database, db_conn, hs)
-
-        # We pull out the current federation stream position now so that we
-        # always have a known value for the federation position in memory so
-        # that we don't have to bounce via a deferred once when we start the
-        # replication streams.
-        self.federation_out_pos_startup = self._get_federation_out_pos(db_conn)
-
-    def _get_federation_out_pos(self, db_conn):
-        sql = "SELECT stream_id FROM federation_stream_position WHERE type = ?"
-        sql = self.database_engine.convert_param_style(sql)
-
-        txn = db_conn.cursor()
-        txn.execute(sql, ("federation",))
-        rows = txn.fetchall()
-        txn.close()
-
-        return rows[0][0] if rows else -1
-
-
-class FederationSenderServer(HomeServer):
-    DATASTORE_CLASS = FederationSenderSlaveStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
-
-        logger.info("Synapse federation_sender now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return FederationSenderReplicationHandler(self)
-
-
-class FederationSenderReplicationHandler(ReplicationClientHandler):
-    def __init__(self, hs):
-        super(FederationSenderReplicationHandler, self).__init__(hs.get_datastore())
-        self.send_handler = FederationSenderHandler(hs, self)
-
-    async def on_rdata(self, stream_name, token, rows):
-        await super(FederationSenderReplicationHandler, self).on_rdata(
-            stream_name, token, rows
-        )
-        self.send_handler.process_replication_rows(stream_name, token, rows)
-
-    def get_streams_to_replicate(self):
-        args = super(
-            FederationSenderReplicationHandler, self
-        ).get_streams_to_replicate()
-        args.update(self.send_handler.stream_positions())
-        return args
-
-    def on_remote_server_up(self, server: str):
-        """Called when get a new REMOTE_SERVER_UP command."""
-
-        # Let's wake up the transaction queue for the server in case we have
-        # pending stuff to send to it.
-        self.send_handler.wake_destination(server)
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config(
-            "Synapse federation sender", config_options
-        )
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
 
-    assert config.worker_app == "synapse.app.federation_sender"
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    if config.send_federation:
-        sys.stderr.write(
-            "\nThe send_federation must be disabled in the main synapse process"
-            "\nbefore they can be run in a separate worker."
-            "\nPlease add ``send_federation: false`` to the main config"
-            "\n"
-        )
-        sys.exit(1)
-
-    # Force the pushers to start since they will be disabled in the main config
-    config.send_federation = True
-
-    ss = FederationSenderServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-federation-sender", config)
-
-
-class FederationSenderHandler(object):
-    """Processes the replication stream and forwards the appropriate entries
-    to the federation sender.
-    """
-
-    def __init__(self, hs: FederationSenderServer, replication_client):
-        self.store = hs.get_datastore()
-        self._is_mine_id = hs.is_mine_id
-        self.federation_sender = hs.get_federation_sender()
-        self.replication_client = replication_client
-
-        self.federation_position = self.store.federation_out_pos_startup
-        self._fed_position_linearizer = Linearizer(name="_fed_position_linearizer")
-
-        self._last_ack = self.federation_position
-
-        self._room_serials = {}
-        self._room_typing = {}
-
-    def on_start(self):
-        # There may be some events that are persisted but haven't been sent,
-        # so send them now.
-        self.federation_sender.notify_new_events(
-            self.store.get_room_max_stream_ordering()
-        )
-
-    def wake_destination(self, server: str):
-        self.federation_sender.wake_destination(server)
-
-    def stream_positions(self):
-        return {"federation": self.federation_position}
-
-    def process_replication_rows(self, stream_name, token, rows):
-        # The federation stream contains things that we want to send out, e.g.
-        # presence, typing, etc.
-        if stream_name == "federation":
-            send_queue.process_rows_for_federation(self.federation_sender, rows)
-            run_in_background(self.update_token, token)
-
-        # We also need to poke the federation sender when new events happen
-        elif stream_name == "events":
-            self.federation_sender.notify_new_events(token)
-
-        # ... and when new receipts happen
-        elif stream_name == ReceiptsStream.NAME:
-            run_as_background_process(
-                "process_receipts_for_federation", self._on_new_receipts, rows
-            )
-
-        # ... as well as device updates and messages
-        elif stream_name == DeviceListsStream.NAME:
-            hosts = set(row.destination for row in rows)
-            for host in hosts:
-                self.federation_sender.send_device_messages(host)
-
-        elif stream_name == ToDeviceStream.NAME:
-            # The to_device stream includes stuff to be pushed to both local
-            # clients and remote servers, so we ignore entities that start with
-            # '@' (since they'll be local users rather than destinations).
-            hosts = set(row.entity for row in rows if not row.entity.startswith("@"))
-            for host in hosts:
-                self.federation_sender.send_device_messages(host)
-
-    @defer.inlineCallbacks
-    def _on_new_receipts(self, rows):
-        """
-        Args:
-            rows (iterable[synapse.replication.tcp.streams.ReceiptsStreamRow]):
-                new receipts to be processed
-        """
-        for receipt in rows:
-            # we only want to send on receipts for our own users
-            if not self._is_mine_id(receipt.user_id):
-                continue
-            receipt_info = ReadReceipt(
-                receipt.room_id,
-                receipt.receipt_type,
-                receipt.user_id,
-                [receipt.event_id],
-                receipt.data,
-            )
-            yield self.federation_sender.send_read_receipt(receipt_info)
-
-    @defer.inlineCallbacks
-    def update_token(self, token):
-        try:
-            self.federation_position = token
-
-            # We linearize here to ensure we don't have races updating the token
-            with (yield self._fed_position_linearizer.queue(None)):
-                if self._last_ack < self.federation_position:
-                    yield self.store.update_federation_out_pos(
-                        "federation", self.federation_position
-                    )
-
-                    # We ACK this token over replication so that the master can drop
-                    # its in memory queues
-                    self.replication_client.send_federation_ack(
-                        self.federation_position
-                    )
-                    self._last_ack = self.federation_position
-        except Exception:
-            logger.exception("Error updating federation stream position")
+import sys
 
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index 30e435eead..add43147b3 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -13,241 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.api.errors import HttpResponseException, SynapseError
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.http.server import JsonResource
-from synapse.http.servlet import RestServlet, parse_json_object_from_request
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import BaseSlavedStore
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
-from synapse.replication.slave.storage.devices import SlavedDeviceStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.rest.client.v2_alpha._base import client_patterns
-from synapse.server import HomeServer
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.frontend_proxy")
-
-
-class PresenceStatusStubServlet(RestServlet):
-    PATTERNS = client_patterns("/presence/(?P<user_id>[^/]*)/status")
-
-    def __init__(self, hs):
-        super(PresenceStatusStubServlet, self).__init__()
-        self.http_client = hs.get_simple_http_client()
-        self.auth = hs.get_auth()
-        self.main_uri = hs.config.worker_main_http_uri
-
-    @defer.inlineCallbacks
-    def on_GET(self, request, user_id):
-        # Pass through the auth headers, if any, in case the access token
-        # is there.
-        auth_headers = request.requestHeaders.getRawHeaders("Authorization", [])
-        headers = {"Authorization": auth_headers}
-
-        try:
-            result = yield self.http_client.get_json(
-                self.main_uri + request.uri.decode("ascii"), headers=headers
-            )
-        except HttpResponseException as e:
-            raise e.to_synapse_error()
-
-        return 200, result
-
-    @defer.inlineCallbacks
-    def on_PUT(self, request, user_id):
-        yield self.auth.get_user_by_req(request)
-        return 200, {}
-
-
-class KeyUploadServlet(RestServlet):
-    PATTERNS = client_patterns("/keys/upload(/(?P<device_id>[^/]+))?$")
-
-    def __init__(self, hs):
-        """
-        Args:
-            hs (synapse.server.HomeServer): server
-        """
-        super(KeyUploadServlet, self).__init__()
-        self.auth = hs.get_auth()
-        self.store = hs.get_datastore()
-        self.http_client = hs.get_simple_http_client()
-        self.main_uri = hs.config.worker_main_http_uri
-
-    @defer.inlineCallbacks
-    def on_POST(self, request, device_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
-        user_id = requester.user.to_string()
-        body = parse_json_object_from_request(request)
-
-        if device_id is not None:
-            # passing the device_id here is deprecated; however, we allow it
-            # for now for compatibility with older clients.
-            if requester.device_id is not None and device_id != requester.device_id:
-                logger.warning(
-                    "Client uploading keys for a different device "
-                    "(logged in as %s, uploading for %s)",
-                    requester.device_id,
-                    device_id,
-                )
-        else:
-            device_id = requester.device_id
-
-        if device_id is None:
-            raise SynapseError(
-                400, "To upload keys, you must pass device_id when authenticating"
-            )
-
-        if body:
-            # They're actually trying to upload something, proxy to main synapse.
-            # Pass through the auth headers, if any, in case the access token
-            # is there.
-            auth_headers = request.requestHeaders.getRawHeaders(b"Authorization", [])
-            headers = {"Authorization": auth_headers}
-            result = yield self.http_client.post_json_get_json(
-                self.main_uri + request.uri.decode("ascii"), body, headers=headers
-            )
-
-            return 200, result
-        else:
-            # Just interested in counts.
-            result = yield self.store.count_e2e_one_time_keys(user_id, device_id)
-            return 200, {"one_time_key_counts": result}
-
-
-class FrontendProxySlavedStore(
-    SlavedDeviceStore,
-    SlavedClientIpStore,
-    SlavedApplicationServiceStore,
-    SlavedRegistrationStore,
-    BaseSlavedStore,
-):
-    pass
 
+import sys
 
-class FrontendProxyServer(HomeServer):
-    DATASTORE_CLASS = FrontendProxySlavedStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-                elif name == "client":
-                    resource = JsonResource(self, canonical_json=False)
-                    KeyUploadServlet(self).register(resource)
-
-                    # If presence is disabled, use the stub servlet that does
-                    # not allow sending presence
-                    if not self.config.use_presence:
-                        PresenceStatusStubServlet(self).register(resource)
-
-                    resources.update(
-                        {
-                            "/_matrix/client/r0": resource,
-                            "/_matrix/client/unstable": resource,
-                            "/_matrix/client/v2_alpha": resource,
-                            "/_matrix/client/api/v1": resource,
-                        }
-                    )
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-            reactor=self.get_reactor(),
-        )
-
-        logger.info("Synapse client reader now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return ReplicationClientHandler(self.get_datastore())
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config("Synapse frontend proxy", config_options)
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.frontend_proxy"
-
-    assert config.worker_main_http_uri is not None
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    ss = FrontendProxyServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-frontend-proxy", config)
-
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/generic_worker.py b/synapse/app/generic_worker.py
new file mode 100644
index 0000000000..30efd39092
--- /dev/null
+++ b/synapse/app/generic_worker.py
@@ -0,0 +1,917 @@
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+# Copyright 2016 OpenMarket Ltd
+# Copyright 2020 The Matrix.org Foundation C.I.C.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+import contextlib
+import logging
+import sys
+
+from twisted.internet import defer, reactor
+from twisted.web.resource import NoResource
+
+import synapse
+import synapse.events
+from synapse.api.constants import EventTypes
+from synapse.api.errors import HttpResponseException, SynapseError
+from synapse.api.urls import (
+    CLIENT_API_PREFIX,
+    FEDERATION_PREFIX,
+    LEGACY_MEDIA_PREFIX,
+    MEDIA_PREFIX,
+    SERVER_KEY_V2_PREFIX,
+)
+from synapse.app import _base
+from synapse.config._base import ConfigError
+from synapse.config.homeserver import HomeServerConfig
+from synapse.config.logger import setup_logging
+from synapse.federation import send_queue
+from synapse.federation.transport.server import TransportLayerServer
+from synapse.handlers.presence import PresenceHandler, get_interested_parties
+from synapse.http.server import JsonResource
+from synapse.http.servlet import RestServlet, parse_json_object_from_request
+from synapse.http.site import SynapseSite
+from synapse.logging.context import LoggingContext, run_in_background
+from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
+from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.replication.slave.storage._base import BaseSlavedStore, __func__
+from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
+from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
+from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
+from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
+from synapse.replication.slave.storage.devices import SlavedDeviceStore
+from synapse.replication.slave.storage.directory import DirectoryStore
+from synapse.replication.slave.storage.events import SlavedEventStore
+from synapse.replication.slave.storage.filtering import SlavedFilteringStore
+from synapse.replication.slave.storage.groups import SlavedGroupServerStore
+from synapse.replication.slave.storage.keys import SlavedKeyStore
+from synapse.replication.slave.storage.presence import SlavedPresenceStore
+from synapse.replication.slave.storage.profile import SlavedProfileStore
+from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
+from synapse.replication.slave.storage.pushers import SlavedPusherStore
+from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
+from synapse.replication.slave.storage.registration import SlavedRegistrationStore
+from synapse.replication.slave.storage.room import RoomStore
+from synapse.replication.slave.storage.transactions import SlavedTransactionStore
+from synapse.replication.tcp.client import ReplicationClientHandler
+from synapse.replication.tcp.streams._base import (
+    DeviceListsStream,
+    ReceiptsStream,
+    ToDeviceStream,
+)
+from synapse.replication.tcp.streams.events import EventsStreamEventRow, EventsStreamRow
+from synapse.rest.admin import register_servlets_for_media_repo
+from synapse.rest.client.v1 import events
+from synapse.rest.client.v1.initial_sync import InitialSyncRestServlet
+from synapse.rest.client.v1.login import LoginRestServlet
+from synapse.rest.client.v1.profile import (
+    ProfileAvatarURLRestServlet,
+    ProfileDisplaynameRestServlet,
+    ProfileRestServlet,
+)
+from synapse.rest.client.v1.push_rule import PushRuleRestServlet
+from synapse.rest.client.v1.room import (
+    JoinedRoomMemberListRestServlet,
+    JoinRoomAliasServlet,
+    PublicRoomListRestServlet,
+    RoomEventContextServlet,
+    RoomInitialSyncRestServlet,
+    RoomMemberListRestServlet,
+    RoomMembershipRestServlet,
+    RoomMessageListRestServlet,
+    RoomSendEventRestServlet,
+    RoomStateEventRestServlet,
+    RoomStateRestServlet,
+)
+from synapse.rest.client.v1.voip import VoipRestServlet
+from synapse.rest.client.v2_alpha import groups, sync, user_directory
+from synapse.rest.client.v2_alpha._base import client_patterns
+from synapse.rest.client.v2_alpha.account import ThreepidRestServlet
+from synapse.rest.client.v2_alpha.keys import KeyChangesServlet, KeyQueryServlet
+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.media_repository import MediaRepositoryStore
+from synapse.storage.data_stores.main.monthly_active_users import (
+    MonthlyActiveUsersWorkerStore,
+)
+from synapse.storage.data_stores.main.presence import UserPresenceState
+from synapse.storage.data_stores.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
+from synapse.util.manhole import manhole
+from synapse.util.stringutils import random_string
+from synapse.util.versionstring import get_version_string
+
+logger = logging.getLogger("synapse.app.generic_worker")
+
+
+class PresenceStatusStubServlet(RestServlet):
+    """If presence is disabled this servlet can be used to stub out setting
+    presence status, while proxying the getters to the master instance.
+    """
+
+    PATTERNS = client_patterns("/presence/(?P<user_id>[^/]*)/status")
+
+    def __init__(self, hs):
+        super(PresenceStatusStubServlet, self).__init__()
+        self.http_client = hs.get_simple_http_client()
+        self.auth = hs.get_auth()
+        self.main_uri = hs.config.worker_main_http_uri
+
+    async def on_GET(self, request, user_id):
+        # Pass through the auth headers, if any, in case the access token
+        # is there.
+        auth_headers = request.requestHeaders.getRawHeaders("Authorization", [])
+        headers = {"Authorization": auth_headers}
+
+        try:
+            result = await self.http_client.get_json(
+                self.main_uri + request.uri.decode("ascii"), headers=headers
+            )
+        except HttpResponseException as e:
+            raise e.to_synapse_error()
+
+        return 200, result
+
+    async def on_PUT(self, request, user_id):
+        await self.auth.get_user_by_req(request)
+        return 200, {}
+
+
+class KeyUploadServlet(RestServlet):
+    """An implementation of the `KeyUploadServlet` that responds to read only
+    requests, but otherwise proxies through to the master instance.
+    """
+
+    PATTERNS = client_patterns("/keys/upload(/(?P<device_id>[^/]+))?$")
+
+    def __init__(self, hs):
+        """
+        Args:
+            hs (synapse.server.HomeServer): server
+        """
+        super(KeyUploadServlet, self).__init__()
+        self.auth = hs.get_auth()
+        self.store = hs.get_datastore()
+        self.http_client = hs.get_simple_http_client()
+        self.main_uri = hs.config.worker_main_http_uri
+
+    async def on_POST(self, request, device_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
+        user_id = requester.user.to_string()
+        body = parse_json_object_from_request(request)
+
+        if device_id is not None:
+            # passing the device_id here is deprecated; however, we allow it
+            # for now for compatibility with older clients.
+            if requester.device_id is not None and device_id != requester.device_id:
+                logger.warning(
+                    "Client uploading keys for a different device "
+                    "(logged in as %s, uploading for %s)",
+                    requester.device_id,
+                    device_id,
+                )
+        else:
+            device_id = requester.device_id
+
+        if device_id is None:
+            raise SynapseError(
+                400, "To upload keys, you must pass device_id when authenticating"
+            )
+
+        if body:
+            # They're actually trying to upload something, proxy to main synapse.
+            # Pass through the auth headers, if any, in case the access token
+            # is there.
+            auth_headers = request.requestHeaders.getRawHeaders(b"Authorization", [])
+            headers = {"Authorization": auth_headers}
+            result = await self.http_client.post_json_get_json(
+                self.main_uri + request.uri.decode("ascii"), body, headers=headers
+            )
+
+            return 200, result
+        else:
+            # Just interested in counts.
+            result = await self.store.count_e2e_one_time_keys(user_id, device_id)
+            return 200, {"one_time_key_counts": result}
+
+
+UPDATE_SYNCING_USERS_MS = 10 * 1000
+
+
+class GenericWorkerPresence(object):
+    def __init__(self, hs):
+        self.hs = hs
+        self.is_mine_id = hs.is_mine_id
+        self.http_client = hs.get_simple_http_client()
+        self.store = hs.get_datastore()
+        self.user_to_num_current_syncs = {}
+        self.clock = hs.get_clock()
+        self.notifier = hs.get_notifier()
+
+        active_presence = self.store.take_presence_startup_info()
+        self.user_to_current_state = {state.user_id: state for state in active_presence}
+
+        # user_id -> last_sync_ms. Lists the users that have stopped syncing
+        # but we haven't notified the master of that yet
+        self.users_going_offline = {}
+
+        self._send_stop_syncing_loop = self.clock.looping_call(
+            self.send_stop_syncing, UPDATE_SYNCING_USERS_MS
+        )
+
+        self.process_id = random_string(16)
+        logger.info("Presence process_id is %r", self.process_id)
+
+    def send_user_sync(self, user_id, is_syncing, last_sync_ms):
+        if self.hs.config.use_presence:
+            self.hs.get_tcp_replication().send_user_sync(
+                user_id, is_syncing, last_sync_ms
+            )
+
+    def mark_as_coming_online(self, user_id):
+        """A user has started syncing. Send a UserSync to the master, unless they
+        had recently stopped syncing.
+
+        Args:
+            user_id (str)
+        """
+        going_offline = self.users_going_offline.pop(user_id, None)
+        if not going_offline:
+            # Safe to skip because we haven't yet told the master they were offline
+            self.send_user_sync(user_id, True, self.clock.time_msec())
+
+    def mark_as_going_offline(self, user_id):
+        """A user has stopped syncing. We wait before notifying the master as
+        its likely they'll come back soon. This allows us to avoid sending
+        a stopped syncing immediately followed by a started syncing notification
+        to the master
+
+        Args:
+            user_id (str)
+        """
+        self.users_going_offline[user_id] = self.clock.time_msec()
+
+    def send_stop_syncing(self):
+        """Check if there are any users who have stopped syncing a while ago
+        and haven't come back yet. If there are poke the master about them.
+        """
+        now = self.clock.time_msec()
+        for user_id, last_sync_ms in list(self.users_going_offline.items()):
+            if now - last_sync_ms > UPDATE_SYNCING_USERS_MS:
+                self.users_going_offline.pop(user_id, None)
+                self.send_user_sync(user_id, False, last_sync_ms)
+
+    def set_state(self, user, state, ignore_status_msg=False):
+        # TODO Hows this supposed to work?
+        return defer.succeed(None)
+
+    get_states = __func__(PresenceHandler.get_states)
+    get_state = __func__(PresenceHandler.get_state)
+    current_state_for_users = __func__(PresenceHandler.current_state_for_users)
+
+    def user_syncing(self, user_id, affect_presence):
+        if affect_presence:
+            curr_sync = self.user_to_num_current_syncs.get(user_id, 0)
+            self.user_to_num_current_syncs[user_id] = curr_sync + 1
+
+            # If we went from no in flight sync to some, notify replication
+            if self.user_to_num_current_syncs[user_id] == 1:
+                self.mark_as_coming_online(user_id)
+
+        def _end():
+            # We check that the user_id is in user_to_num_current_syncs because
+            # user_to_num_current_syncs may have been cleared if we are
+            # shutting down.
+            if affect_presence and user_id in self.user_to_num_current_syncs:
+                self.user_to_num_current_syncs[user_id] -= 1
+
+                # If we went from one in flight sync to non, notify replication
+                if self.user_to_num_current_syncs[user_id] == 0:
+                    self.mark_as_going_offline(user_id)
+
+        @contextlib.contextmanager
+        def _user_syncing():
+            try:
+                yield
+            finally:
+                _end()
+
+        return defer.succeed(_user_syncing())
+
+    @defer.inlineCallbacks
+    def notify_from_replication(self, states, stream_id):
+        parties = yield get_interested_parties(self.store, states)
+        room_ids_to_states, users_to_states = parties
+
+        self.notifier.on_new_event(
+            "presence_key",
+            stream_id,
+            rooms=room_ids_to_states.keys(),
+            users=users_to_states.keys(),
+        )
+
+    @defer.inlineCallbacks
+    def process_replication_rows(self, token, rows):
+        states = [
+            UserPresenceState(
+                row.user_id,
+                row.state,
+                row.last_active_ts,
+                row.last_federation_update_ts,
+                row.last_user_sync_ts,
+                row.status_msg,
+                row.currently_active,
+            )
+            for row in rows
+        ]
+
+        for state in states:
+            self.user_to_current_state[state.user_id] = state
+
+        stream_id = token
+        yield self.notify_from_replication(states, stream_id)
+
+    def get_currently_syncing_users(self):
+        if self.hs.config.use_presence:
+            return [
+                user_id
+                for user_id, count in self.user_to_num_current_syncs.items()
+                if count > 0
+            ]
+        else:
+            return set()
+
+
+class GenericWorkerTyping(object):
+    def __init__(self, hs):
+        self._latest_room_serial = 0
+        self._reset()
+
+    def _reset(self):
+        """
+        Reset the typing handler's data caches.
+        """
+        # map room IDs to serial numbers
+        self._room_serials = {}
+        # map room IDs to sets of users currently typing
+        self._room_typing = {}
+
+    def stream_positions(self):
+        # We must update this typing token from the response of the previous
+        # sync. In particular, the stream id may "reset" back to zero/a low
+        # value which we *must* use for the next replication request.
+        return {"typing": self._latest_room_serial}
+
+    def process_replication_rows(self, token, rows):
+        if self._latest_room_serial > token:
+            # The master has gone backwards. To prevent inconsistent data, just
+            # clear everything.
+            self._reset()
+
+        # Set the latest serial token to whatever the server gave us.
+        self._latest_room_serial = token
+
+        for row in rows:
+            self._room_serials[row.room_id] = token
+            self._room_typing[row.room_id] = row.user_ids
+
+
+class GenericWorkerSlavedStore(
+    # FIXME(#3714): We need to add UserDirectoryStore as we write directly
+    # rather than going via the correct worker.
+    UserDirectoryStore,
+    SlavedDeviceInboxStore,
+    SlavedDeviceStore,
+    SlavedReceiptsStore,
+    SlavedPushRuleStore,
+    SlavedGroupServerStore,
+    SlavedAccountDataStore,
+    SlavedPusherStore,
+    SlavedEventStore,
+    SlavedKeyStore,
+    RoomStore,
+    DirectoryStore,
+    SlavedApplicationServiceStore,
+    SlavedRegistrationStore,
+    SlavedTransactionStore,
+    SlavedProfileStore,
+    SlavedClientIpStore,
+    SlavedPresenceStore,
+    SlavedFilteringStore,
+    MonthlyActiveUsersWorkerStore,
+    MediaRepositoryStore,
+    BaseSlavedStore,
+):
+    def __init__(self, database, db_conn, hs):
+        super(GenericWorkerSlavedStore, self).__init__(database, db_conn, hs)
+
+        # We pull out the current federation stream position now so that we
+        # always have a known value for the federation position in memory so
+        # that we don't have to bounce via a deferred once when we start the
+        # replication streams.
+        self.federation_out_pos_startup = self._get_federation_out_pos(db_conn)
+
+    def _get_federation_out_pos(self, db_conn):
+        sql = "SELECT stream_id FROM federation_stream_position WHERE type = ?"
+        sql = self.database_engine.convert_param_style(sql)
+
+        txn = db_conn.cursor()
+        txn.execute(sql, ("federation",))
+        rows = txn.fetchall()
+        txn.close()
+
+        return rows[0][0] if rows else -1
+
+
+class GenericWorkerServer(HomeServer):
+    DATASTORE_CLASS = GenericWorkerSlavedStore
+
+    def _listen_http(self, listener_config):
+        port = listener_config["port"]
+        bind_addresses = listener_config["bind_addresses"]
+        site_tag = listener_config.get("tag", port)
+        resources = {}
+        for res in listener_config["resources"]:
+            for name in res["names"]:
+                if name == "metrics":
+                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
+                elif name == "client":
+                    resource = JsonResource(self, canonical_json=False)
+
+                    PublicRoomListRestServlet(self).register(resource)
+                    RoomMemberListRestServlet(self).register(resource)
+                    JoinedRoomMemberListRestServlet(self).register(resource)
+                    RoomStateRestServlet(self).register(resource)
+                    RoomEventContextServlet(self).register(resource)
+                    RoomMessageListRestServlet(self).register(resource)
+                    RegisterRestServlet(self).register(resource)
+                    LoginRestServlet(self).register(resource)
+                    ThreepidRestServlet(self).register(resource)
+                    KeyQueryServlet(self).register(resource)
+                    KeyChangesServlet(self).register(resource)
+                    VoipRestServlet(self).register(resource)
+                    PushRuleRestServlet(self).register(resource)
+                    VersionsRestServlet(self).register(resource)
+                    RoomSendEventRestServlet(self).register(resource)
+                    RoomMembershipRestServlet(self).register(resource)
+                    RoomStateEventRestServlet(self).register(resource)
+                    JoinRoomAliasServlet(self).register(resource)
+                    ProfileAvatarURLRestServlet(self).register(resource)
+                    ProfileDisplaynameRestServlet(self).register(resource)
+                    ProfileRestServlet(self).register(resource)
+                    KeyUploadServlet(self).register(resource)
+
+                    sync.register_servlets(self, resource)
+                    events.register_servlets(self, resource)
+                    InitialSyncRestServlet(self).register(resource)
+                    RoomInitialSyncRestServlet(self).register(resource)
+
+                    user_directory.register_servlets(self, resource)
+
+                    # If presence is disabled, use the stub servlet that does
+                    # not allow sending presence
+                    if not self.config.use_presence:
+                        PresenceStatusStubServlet(self).register(resource)
+
+                    groups.register_servlets(self, resource)
+
+                    resources.update({CLIENT_API_PREFIX: resource})
+                elif name == "federation":
+                    resources.update({FEDERATION_PREFIX: TransportLayerServer(self)})
+                elif name == "media":
+                    media_repo = self.get_media_repository_resource()
+
+                    # We need to serve the admin servlets for media on the
+                    # worker.
+                    admin_resource = JsonResource(self, canonical_json=False)
+                    register_servlets_for_media_repo(self, admin_resource)
+
+                    resources.update(
+                        {
+                            MEDIA_PREFIX: media_repo,
+                            LEGACY_MEDIA_PREFIX: media_repo,
+                            "/_synapse/admin": admin_resource,
+                        }
+                    )
+
+                if name == "openid" and "federation" not in res["names"]:
+                    # Only load the openid resource separately if federation resource
+                    # is not specified since federation resource includes openid
+                    # resource.
+                    resources.update(
+                        {
+                            FEDERATION_PREFIX: TransportLayerServer(
+                                self, servlet_groups=["openid"]
+                            )
+                        }
+                    )
+
+                if name in ["keys", "federation"]:
+                    resources[SERVER_KEY_V2_PREFIX] = KeyApiV2Resource(self)
+
+        root_resource = create_resource_tree(resources, NoResource())
+
+        _base.listen_tcp(
+            bind_addresses,
+            port,
+            SynapseSite(
+                "synapse.access.http.%s" % (site_tag,),
+                site_tag,
+                listener_config,
+                root_resource,
+                self.version_string,
+            ),
+            reactor=self.get_reactor(),
+        )
+
+        logger.info("Synapse worker now listening on port %d", port)
+
+    def start_listening(self, listeners):
+        for listener in listeners:
+            if listener["type"] == "http":
+                self._listen_http(listener)
+            elif listener["type"] == "manhole":
+                _base.listen_tcp(
+                    listener["bind_addresses"],
+                    listener["port"],
+                    manhole(
+                        username="matrix", password="rabbithole", globals={"hs": self}
+                    ),
+                )
+            elif listener["type"] == "metrics":
+                if not self.get_config().enable_metrics:
+                    logger.warning(
+                        (
+                            "Metrics listener configured, but "
+                            "enable_metrics is not True!"
+                        )
+                    )
+                else:
+                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
+            else:
+                logger.warning("Unrecognized listener type: %s", listener["type"])
+
+        self.get_tcp_replication().start_replication(self)
+
+    def remove_pusher(self, app_id, push_key, user_id):
+        self.get_tcp_replication().send_remove_pusher(app_id, push_key, user_id)
+
+    def build_tcp_replication(self):
+        return GenericWorkerReplicationHandler(self)
+
+    def build_presence_handler(self):
+        return GenericWorkerPresence(self)
+
+    def build_typing_handler(self):
+        return GenericWorkerTyping(self)
+
+
+class GenericWorkerReplicationHandler(ReplicationClientHandler):
+    def __init__(self, hs):
+        super(GenericWorkerReplicationHandler, self).__init__(hs.get_datastore())
+
+        self.store = hs.get_datastore()
+        self.typing_handler = hs.get_typing_handler()
+        # NB this is a SynchrotronPresence, not a normal PresenceHandler
+        self.presence_handler = hs.get_presence_handler()
+        self.notifier = hs.get_notifier()
+
+        self.notify_pushers = hs.config.start_pushers
+        self.pusher_pool = hs.get_pusherpool()
+
+        if hs.config.send_federation:
+            self.send_handler = FederationSenderHandler(hs, self)
+        else:
+            self.send_handler = None
+
+    async def on_rdata(self, stream_name, token, rows):
+        await super(GenericWorkerReplicationHandler, self).on_rdata(
+            stream_name, token, rows
+        )
+        run_in_background(self.process_and_notify, stream_name, token, rows)
+
+    def get_streams_to_replicate(self):
+        args = super(GenericWorkerReplicationHandler, self).get_streams_to_replicate()
+        args.update(self.typing_handler.stream_positions())
+        if self.send_handler:
+            args.update(self.send_handler.stream_positions())
+        return args
+
+    def get_currently_syncing_users(self):
+        return self.presence_handler.get_currently_syncing_users()
+
+    async def process_and_notify(self, stream_name, token, rows):
+        try:
+            if self.send_handler:
+                self.send_handler.process_replication_rows(stream_name, token, rows)
+
+            if stream_name == "events":
+                # We shouldn't get multiple rows per token for events stream, so
+                # we don't need to optimise this for multiple rows.
+                for row in rows:
+                    if row.type != EventsStreamEventRow.TypeId:
+                        continue
+                    assert isinstance(row, EventsStreamRow)
+
+                    event = await self.store.get_event(
+                        row.data.event_id, allow_rejected=True
+                    )
+                    if event.rejected_reason:
+                        continue
+
+                    extra_users = ()
+                    if event.type == EventTypes.Member:
+                        extra_users = (event.state_key,)
+                    max_token = self.store.get_room_max_stream_ordering()
+                    self.notifier.on_new_room_event(
+                        event, token, max_token, extra_users
+                    )
+
+                await self.pusher_pool.on_new_notifications(token, token)
+            elif stream_name == "push_rules":
+                self.notifier.on_new_event(
+                    "push_rules_key", token, users=[row.user_id for row in rows]
+                )
+            elif stream_name in ("account_data", "tag_account_data"):
+                self.notifier.on_new_event(
+                    "account_data_key", token, users=[row.user_id for row in rows]
+                )
+            elif stream_name == "receipts":
+                self.notifier.on_new_event(
+                    "receipt_key", token, rooms=[row.room_id for row in rows]
+                )
+                await self.pusher_pool.on_new_receipts(
+                    token, token, {row.room_id for row in rows}
+                )
+            elif stream_name == "typing":
+                self.typing_handler.process_replication_rows(token, rows)
+                self.notifier.on_new_event(
+                    "typing_key", token, rooms=[row.room_id for row in rows]
+                )
+            elif stream_name == "to_device":
+                entities = [row.entity for row in rows if row.entity.startswith("@")]
+                if entities:
+                    self.notifier.on_new_event("to_device_key", token, users=entities)
+            elif stream_name == "device_lists":
+                all_room_ids = set()
+                for row in rows:
+                    room_ids = await self.store.get_rooms_for_user(row.user_id)
+                    all_room_ids.update(room_ids)
+                self.notifier.on_new_event("device_list_key", token, rooms=all_room_ids)
+            elif stream_name == "presence":
+                await self.presence_handler.process_replication_rows(token, rows)
+            elif stream_name == "receipts":
+                self.notifier.on_new_event(
+                    "groups_key", token, users=[row.user_id for row in rows]
+                )
+            elif stream_name == "pushers":
+                for row in rows:
+                    if row.deleted:
+                        self.stop_pusher(row.user_id, row.app_id, row.pushkey)
+                    else:
+                        await self.start_pusher(row.user_id, row.app_id, row.pushkey)
+        except Exception:
+            logger.exception("Error processing replication")
+
+    def stop_pusher(self, user_id, app_id, pushkey):
+        if not self.notify_pushers:
+            return
+
+        key = "%s:%s" % (app_id, pushkey)
+        pushers_for_user = self.pusher_pool.pushers.get(user_id, {})
+        pusher = pushers_for_user.pop(key, None)
+        if pusher is None:
+            return
+        logger.info("Stopping pusher %r / %r", user_id, key)
+        pusher.on_stop()
+
+    async def start_pusher(self, user_id, app_id, pushkey):
+        if not self.notify_pushers:
+            return
+
+        key = "%s:%s" % (app_id, pushkey)
+        logger.info("Starting pusher %r / %r", user_id, key)
+        return await self.pusher_pool.start_pusher_by_id(app_id, pushkey, user_id)
+
+    def on_remote_server_up(self, server: str):
+        """Called when get a new REMOTE_SERVER_UP command."""
+
+        # Let's wake up the transaction queue for the server in case we have
+        # pending stuff to send to it.
+        if self.send_handler:
+            self.send_handler.wake_destination(server)
+
+
+class FederationSenderHandler(object):
+    """Processes the replication stream and forwards the appropriate entries
+    to the federation sender.
+    """
+
+    def __init__(self, hs: GenericWorkerServer, replication_client):
+        self.store = hs.get_datastore()
+        self._is_mine_id = hs.is_mine_id
+        self.federation_sender = hs.get_federation_sender()
+        self.replication_client = replication_client
+
+        self.federation_position = self.store.federation_out_pos_startup
+        self._fed_position_linearizer = Linearizer(name="_fed_position_linearizer")
+
+        self._last_ack = self.federation_position
+
+        self._room_serials = {}
+        self._room_typing = {}
+
+    def on_start(self):
+        # There may be some events that are persisted but haven't been sent,
+        # so send them now.
+        self.federation_sender.notify_new_events(
+            self.store.get_room_max_stream_ordering()
+        )
+
+    def wake_destination(self, server: str):
+        self.federation_sender.wake_destination(server)
+
+    def stream_positions(self):
+        return {"federation": self.federation_position}
+
+    def process_replication_rows(self, stream_name, token, rows):
+        # The federation stream contains things that we want to send out, e.g.
+        # presence, typing, etc.
+        if stream_name == "federation":
+            send_queue.process_rows_for_federation(self.federation_sender, rows)
+            run_in_background(self.update_token, token)
+
+        # We also need to poke the federation sender when new events happen
+        elif stream_name == "events":
+            self.federation_sender.notify_new_events(token)
+
+        # ... and when new receipts happen
+        elif stream_name == ReceiptsStream.NAME:
+            run_as_background_process(
+                "process_receipts_for_federation", self._on_new_receipts, rows
+            )
+
+        # ... as well as device updates and messages
+        elif stream_name == DeviceListsStream.NAME:
+            hosts = {row.destination for row in rows}
+            for host in hosts:
+                self.federation_sender.send_device_messages(host)
+
+        elif stream_name == ToDeviceStream.NAME:
+            # The to_device stream includes stuff to be pushed to both local
+            # clients and remote servers, so we ignore entities that start with
+            # '@' (since they'll be local users rather than destinations).
+            hosts = {row.entity for row in rows if not row.entity.startswith("@")}
+            for host in hosts:
+                self.federation_sender.send_device_messages(host)
+
+    async def _on_new_receipts(self, rows):
+        """
+        Args:
+            rows (iterable[synapse.replication.tcp.streams.ReceiptsStreamRow]):
+                new receipts to be processed
+        """
+        for receipt in rows:
+            # we only want to send on receipts for our own users
+            if not self._is_mine_id(receipt.user_id):
+                continue
+            receipt_info = ReadReceipt(
+                receipt.room_id,
+                receipt.receipt_type,
+                receipt.user_id,
+                [receipt.event_id],
+                receipt.data,
+            )
+            await self.federation_sender.send_read_receipt(receipt_info)
+
+    async def update_token(self, token):
+        try:
+            self.federation_position = token
+
+            # We linearize here to ensure we don't have races updating the token
+            with (await self._fed_position_linearizer.queue(None)):
+                if self._last_ack < self.federation_position:
+                    await self.store.update_federation_out_pos(
+                        "federation", self.federation_position
+                    )
+
+                    # We ACK this token over replication so that the master can drop
+                    # its in memory queues
+                    self.replication_client.send_federation_ack(
+                        self.federation_position
+                    )
+                    self._last_ack = self.federation_position
+        except Exception:
+            logger.exception("Error updating federation stream position")
+
+
+def start(config_options):
+    try:
+        config = HomeServerConfig.load_config("Synapse worker", config_options)
+    except ConfigError as e:
+        sys.stderr.write("\n" + str(e) + "\n")
+        sys.exit(1)
+
+    # For backwards compatibility let any of the old app names.
+    assert config.worker_app in (
+        "synapse.app.appservice",
+        "synapse.app.client_reader",
+        "synapse.app.event_creator",
+        "synapse.app.federation_reader",
+        "synapse.app.federation_sender",
+        "synapse.app.frontend_proxy",
+        "synapse.app.generic_worker",
+        "synapse.app.media_repository",
+        "synapse.app.pusher",
+        "synapse.app.synchrotron",
+        "synapse.app.user_dir",
+    )
+
+    if config.worker_app == "synapse.app.appservice":
+        if config.notify_appservices:
+            sys.stderr.write(
+                "\nThe appservices must be disabled in the main synapse process"
+                "\nbefore they can be run in a separate worker."
+                "\nPlease add ``notify_appservices: false`` to the main config"
+                "\n"
+            )
+            sys.exit(1)
+
+        # Force the appservice to start since they will be disabled in the main config
+        config.notify_appservices = True
+
+    if config.worker_app == "synapse.app.pusher":
+        if config.start_pushers:
+            sys.stderr.write(
+                "\nThe pushers must be disabled in the main synapse process"
+                "\nbefore they can be run in a separate worker."
+                "\nPlease add ``start_pushers: false`` to the main config"
+                "\n"
+            )
+            sys.exit(1)
+
+        # Force the pushers to start since they will be disabled in the main config
+        config.start_pushers = True
+
+    if config.worker_app == "synapse.app.user_dir":
+        if config.update_user_directory:
+            sys.stderr.write(
+                "\nThe update_user_directory must be disabled in the main synapse process"
+                "\nbefore they can be run in a separate worker."
+                "\nPlease add ``update_user_directory: false`` to the main config"
+                "\n"
+            )
+            sys.exit(1)
+
+        # Force the pushers to start since they will be disabled in the main config
+        config.update_user_directory = True
+
+    if config.worker_app == "synapse.app.federation_sender":
+        if config.send_federation:
+            sys.stderr.write(
+                "\nThe send_federation must be disabled in the main synapse process"
+                "\nbefore they can be run in a separate worker."
+                "\nPlease add ``send_federation: false`` to the main config"
+                "\n"
+            )
+            sys.exit(1)
+
+        # Force the pushers to start since they will be disabled in the main config
+        config.send_federation = True
+
+    synapse.events.USE_FROZEN_DICTS = config.use_frozen_dicts
+
+    ss = GenericWorkerServer(
+        config.server_name,
+        config=config,
+        version_string="Synapse/" + get_version_string(synapse),
+    )
+
+    setup_logging(ss, config, use_worker_options=True)
+
+    ss.setup()
+    reactor.addSystemEventTrigger(
+        "before", "startup", _base.start, ss, config.worker_listeners
+    )
+
+    _base.start_worker_reactor("synapse-generic-worker", config)
+
+
+if __name__ == "__main__":
+    with LoggingContext("main"):
+        start(sys.argv[1:])
diff --git a/synapse/app/media_repository.py b/synapse/app/media_repository.py
index 5b5832214a..add43147b3 100644
--- a/synapse/app/media_repository.py
+++ b/synapse/app/media_repository.py
@@ -13,162 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.api.urls import LEGACY_MEDIA_PREFIX, MEDIA_PREFIX
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.http.server import JsonResource
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import BaseSlavedStore
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.slave.storage.room import RoomStore
-from synapse.replication.slave.storage.transactions import SlavedTransactionStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.rest.admin import register_servlets_for_media_repo
-from synapse.server import HomeServer
-from synapse.storage.data_stores.main.media_repository import MediaRepositoryStore
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.media_repository")
-
-
-class MediaRepositorySlavedStore(
-    RoomStore,
-    SlavedApplicationServiceStore,
-    SlavedRegistrationStore,
-    SlavedClientIpStore,
-    SlavedTransactionStore,
-    BaseSlavedStore,
-    MediaRepositoryStore,
-):
-    pass
-
-
-class MediaRepositoryServer(HomeServer):
-    DATASTORE_CLASS = MediaRepositorySlavedStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-                elif name == "media":
-                    media_repo = self.get_media_repository_resource()
-
-                    # We need to serve the admin servlets for media on the
-                    # worker.
-                    admin_resource = JsonResource(self, canonical_json=False)
-                    register_servlets_for_media_repo(self, admin_resource)
-
-                    resources.update(
-                        {
-                            MEDIA_PREFIX: media_repo,
-                            LEGACY_MEDIA_PREFIX: media_repo,
-                            "/_synapse/admin": admin_resource,
-                        }
-                    )
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
 
-        logger.info("Synapse media repository now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return ReplicationClientHandler(self.get_datastore())
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config(
-            "Synapse media repository", config_options
-        )
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.media_repository"
-
-    if config.enable_media_repo:
-        _base.quit_with_error(
-            "enable_media_repo must be disabled in the main synapse process\n"
-            "before the media repo can be run in a separate worker.\n"
-            "Please add ``enable_media_repo: false`` to the main config\n"
-        )
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    ss = MediaRepositoryServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-media-repository", config)
+import sys
 
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index e46b6ac598..add43147b3 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -13,213 +13,12 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import logging
-import sys
-
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext, run_in_background
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import __func__
-from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.pushers import SlavedPusherStore
-from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
-from synapse.replication.slave.storage.room import RoomStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.server import HomeServer
-from synapse.storage import DataStore
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.pusher")
-
-
-class PusherSlaveStore(
-    SlavedEventStore,
-    SlavedPusherStore,
-    SlavedReceiptsStore,
-    SlavedAccountDataStore,
-    RoomStore,
-):
-    update_pusher_last_stream_ordering_and_success = __func__(
-        DataStore.update_pusher_last_stream_ordering_and_success
-    )
-
-    update_pusher_failing_since = __func__(DataStore.update_pusher_failing_since)
-
-    update_pusher_last_stream_ordering = __func__(
-        DataStore.update_pusher_last_stream_ordering
-    )
-
-    get_throttle_params_by_room = __func__(DataStore.get_throttle_params_by_room)
-
-    set_throttle_params = __func__(DataStore.set_throttle_params)
-
-    get_time_of_last_push_action_before = __func__(
-        DataStore.get_time_of_last_push_action_before
-    )
-
-    get_profile_displayname = __func__(DataStore.get_profile_displayname)
-
-
-class PusherServer(HomeServer):
-    DATASTORE_CLASS = PusherSlaveStore
-
-    def remove_pusher(self, app_id, push_key, user_id):
-        self.get_tcp_replication().send_remove_pusher(app_id, push_key, user_id)
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
-
-        logger.info("Synapse pusher now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
 
-    def build_tcp_replication(self):
-        return PusherReplicationHandler(self)
-
-
-class PusherReplicationHandler(ReplicationClientHandler):
-    def __init__(self, hs):
-        super(PusherReplicationHandler, self).__init__(hs.get_datastore())
-
-        self.pusher_pool = hs.get_pusherpool()
-
-    async def on_rdata(self, stream_name, token, rows):
-        await super(PusherReplicationHandler, self).on_rdata(stream_name, token, rows)
-        run_in_background(self.poke_pushers, stream_name, token, rows)
-
-    @defer.inlineCallbacks
-    def poke_pushers(self, stream_name, token, rows):
-        try:
-            if stream_name == "pushers":
-                for row in rows:
-                    if row.deleted:
-                        yield self.stop_pusher(row.user_id, row.app_id, row.pushkey)
-                    else:
-                        yield self.start_pusher(row.user_id, row.app_id, row.pushkey)
-            elif stream_name == "events":
-                yield self.pusher_pool.on_new_notifications(token, token)
-            elif stream_name == "receipts":
-                yield self.pusher_pool.on_new_receipts(
-                    token, token, set(row.room_id for row in rows)
-                )
-        except Exception:
-            logger.exception("Error poking pushers")
-
-    def stop_pusher(self, user_id, app_id, pushkey):
-        key = "%s:%s" % (app_id, pushkey)
-        pushers_for_user = self.pusher_pool.pushers.get(user_id, {})
-        pusher = pushers_for_user.pop(key, None)
-        if pusher is None:
-            return
-        logger.info("Stopping pusher %r / %r", user_id, key)
-        pusher.on_stop()
-
-    def start_pusher(self, user_id, app_id, pushkey):
-        key = "%s:%s" % (app_id, pushkey)
-        logger.info("Starting pusher %r / %r", user_id, key)
-        return self.pusher_pool.start_pusher_by_id(app_id, pushkey, user_id)
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config("Synapse pusher", config_options)
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.pusher"
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    if config.start_pushers:
-        sys.stderr.write(
-            "\nThe pushers must be disabled in the main synapse process"
-            "\nbefore they can be run in a separate worker."
-            "\nPlease add ``start_pushers: false`` to the main config"
-            "\n"
-        )
-        sys.exit(1)
-
-    # Force the pushers to start since they will be disabled in the main config
-    config.start_pushers = True
-
-    ps = PusherServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ps, config, use_worker_options=True)
-
-    ps.setup()
-
-    def start():
-        _base.start(ps, config.worker_listeners)
-        ps.get_pusherpool().start()
-
-    reactor.addSystemEventTrigger("before", "startup", start)
-
-    _base.start_worker_reactor("synapse-pusher", config)
+import sys
 
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
-        ps = start(sys.argv[1:])
+        start(sys.argv[1:])
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index 8982c0676e..add43147b3 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -13,454 +13,11 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 # See the License for the specific language governing permissions and
 # limitations under the License.
-import contextlib
-import logging
-import sys
-
-from six import iteritems
-
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse.api.constants import EventTypes
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.handlers.presence import PresenceHandler, get_interested_parties
-from synapse.http.server import JsonResource
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext, run_in_background
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import BaseSlavedStore, __func__
-from synapse.replication.slave.storage.account_data import SlavedAccountDataStore
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
-from synapse.replication.slave.storage.deviceinbox import SlavedDeviceInboxStore
-from synapse.replication.slave.storage.devices import SlavedDeviceStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.filtering import SlavedFilteringStore
-from synapse.replication.slave.storage.groups import SlavedGroupServerStore
-from synapse.replication.slave.storage.presence import SlavedPresenceStore
-from synapse.replication.slave.storage.push_rule import SlavedPushRuleStore
-from synapse.replication.slave.storage.receipts import SlavedReceiptsStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.slave.storage.room import RoomStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.replication.tcp.streams.events import EventsStreamEventRow, EventsStreamRow
-from synapse.rest.client.v1 import events
-from synapse.rest.client.v1.initial_sync import InitialSyncRestServlet
-from synapse.rest.client.v1.room import RoomInitialSyncRestServlet
-from synapse.rest.client.v2_alpha import sync
-from synapse.server import HomeServer
-from synapse.storage.data_stores.main.monthly_active_users import (
-    MonthlyActiveUsersWorkerStore,
-)
-from synapse.storage.data_stores.main.presence import UserPresenceState
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.stringutils import random_string
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.synchrotron")
-
-
-class SynchrotronSlavedStore(
-    SlavedReceiptsStore,
-    SlavedAccountDataStore,
-    SlavedApplicationServiceStore,
-    SlavedRegistrationStore,
-    SlavedFilteringStore,
-    SlavedPresenceStore,
-    SlavedGroupServerStore,
-    SlavedDeviceInboxStore,
-    SlavedDeviceStore,
-    SlavedPushRuleStore,
-    SlavedEventStore,
-    SlavedClientIpStore,
-    RoomStore,
-    MonthlyActiveUsersWorkerStore,
-    BaseSlavedStore,
-):
-    pass
-
-
-UPDATE_SYNCING_USERS_MS = 10 * 1000
-
-
-class SynchrotronPresence(object):
-    def __init__(self, hs):
-        self.hs = hs
-        self.is_mine_id = hs.is_mine_id
-        self.http_client = hs.get_simple_http_client()
-        self.store = hs.get_datastore()
-        self.user_to_num_current_syncs = {}
-        self.clock = hs.get_clock()
-        self.notifier = hs.get_notifier()
-
-        active_presence = self.store.take_presence_startup_info()
-        self.user_to_current_state = {state.user_id: state for state in active_presence}
-
-        # user_id -> last_sync_ms. Lists the users that have stopped syncing
-        # but we haven't notified the master of that yet
-        self.users_going_offline = {}
-
-        self._send_stop_syncing_loop = self.clock.looping_call(
-            self.send_stop_syncing, 10 * 1000
-        )
-
-        self.process_id = random_string(16)
-        logger.info("Presence process_id is %r", self.process_id)
-
-    def send_user_sync(self, user_id, is_syncing, last_sync_ms):
-        if self.hs.config.use_presence:
-            self.hs.get_tcp_replication().send_user_sync(
-                user_id, is_syncing, last_sync_ms
-            )
-
-    def mark_as_coming_online(self, user_id):
-        """A user has started syncing. Send a UserSync to the master, unless they
-        had recently stopped syncing.
-
-        Args:
-            user_id (str)
-        """
-        going_offline = self.users_going_offline.pop(user_id, None)
-        if not going_offline:
-            # Safe to skip because we haven't yet told the master they were offline
-            self.send_user_sync(user_id, True, self.clock.time_msec())
-
-    def mark_as_going_offline(self, user_id):
-        """A user has stopped syncing. We wait before notifying the master as
-        its likely they'll come back soon. This allows us to avoid sending
-        a stopped syncing immediately followed by a started syncing notification
-        to the master
-
-        Args:
-            user_id (str)
-        """
-        self.users_going_offline[user_id] = self.clock.time_msec()
-
-    def send_stop_syncing(self):
-        """Check if there are any users who have stopped syncing a while ago
-        and haven't come back yet. If there are poke the master about them.
-        """
-        now = self.clock.time_msec()
-        for user_id, last_sync_ms in list(self.users_going_offline.items()):
-            if now - last_sync_ms > 10 * 1000:
-                self.users_going_offline.pop(user_id, None)
-                self.send_user_sync(user_id, False, last_sync_ms)
-
-    def set_state(self, user, state, ignore_status_msg=False):
-        # TODO Hows this supposed to work?
-        return defer.succeed(None)
-
-    get_states = __func__(PresenceHandler.get_states)
-    get_state = __func__(PresenceHandler.get_state)
-    current_state_for_users = __func__(PresenceHandler.current_state_for_users)
-
-    def user_syncing(self, user_id, affect_presence):
-        if affect_presence:
-            curr_sync = self.user_to_num_current_syncs.get(user_id, 0)
-            self.user_to_num_current_syncs[user_id] = curr_sync + 1
-
-            # If we went from no in flight sync to some, notify replication
-            if self.user_to_num_current_syncs[user_id] == 1:
-                self.mark_as_coming_online(user_id)
-
-        def _end():
-            # We check that the user_id is in user_to_num_current_syncs because
-            # user_to_num_current_syncs may have been cleared if we are
-            # shutting down.
-            if affect_presence and user_id in self.user_to_num_current_syncs:
-                self.user_to_num_current_syncs[user_id] -= 1
-
-                # If we went from one in flight sync to non, notify replication
-                if self.user_to_num_current_syncs[user_id] == 0:
-                    self.mark_as_going_offline(user_id)
-
-        @contextlib.contextmanager
-        def _user_syncing():
-            try:
-                yield
-            finally:
-                _end()
-
-        return defer.succeed(_user_syncing())
-
-    @defer.inlineCallbacks
-    def notify_from_replication(self, states, stream_id):
-        parties = yield get_interested_parties(self.store, states)
-        room_ids_to_states, users_to_states = parties
-
-        self.notifier.on_new_event(
-            "presence_key",
-            stream_id,
-            rooms=room_ids_to_states.keys(),
-            users=users_to_states.keys(),
-        )
-
-    @defer.inlineCallbacks
-    def process_replication_rows(self, token, rows):
-        states = [
-            UserPresenceState(
-                row.user_id,
-                row.state,
-                row.last_active_ts,
-                row.last_federation_update_ts,
-                row.last_user_sync_ts,
-                row.status_msg,
-                row.currently_active,
-            )
-            for row in rows
-        ]
-
-        for state in states:
-            self.user_to_current_state[state.user_id] = state
-
-        stream_id = token
-        yield self.notify_from_replication(states, stream_id)
-
-    def get_currently_syncing_users(self):
-        if self.hs.config.use_presence:
-            return [
-                user_id
-                for user_id, count in iteritems(self.user_to_num_current_syncs)
-                if count > 0
-            ]
-        else:
-            return set()
-
 
-class SynchrotronTyping(object):
-    def __init__(self, hs):
-        self._latest_room_serial = 0
-        self._reset()
-
-    def _reset(self):
-        """
-        Reset the typing handler's data caches.
-        """
-        # map room IDs to serial numbers
-        self._room_serials = {}
-        # map room IDs to sets of users currently typing
-        self._room_typing = {}
-
-    def stream_positions(self):
-        # We must update this typing token from the response of the previous
-        # sync. In particular, the stream id may "reset" back to zero/a low
-        # value which we *must* use for the next replication request.
-        return {"typing": self._latest_room_serial}
-
-    def process_replication_rows(self, token, rows):
-        if self._latest_room_serial > token:
-            # The master has gone backwards. To prevent inconsistent data, just
-            # clear everything.
-            self._reset()
-
-        # Set the latest serial token to whatever the server gave us.
-        self._latest_room_serial = token
-
-        for row in rows:
-            self._room_serials[row.room_id] = token
-            self._room_typing[row.room_id] = row.user_ids
-
-
-class SynchrotronApplicationService(object):
-    def notify_interested_services(self, event):
-        pass
-
-
-class SynchrotronServer(HomeServer):
-    DATASTORE_CLASS = SynchrotronSlavedStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-                elif name == "client":
-                    resource = JsonResource(self, canonical_json=False)
-                    sync.register_servlets(self, resource)
-                    events.register_servlets(self, resource)
-                    InitialSyncRestServlet(self).register(resource)
-                    RoomInitialSyncRestServlet(self).register(resource)
-                    resources.update(
-                        {
-                            "/_matrix/client/r0": resource,
-                            "/_matrix/client/unstable": resource,
-                            "/_matrix/client/v2_alpha": resource,
-                            "/_matrix/client/api/v1": resource,
-                        }
-                    )
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
-
-        logger.info("Synapse synchrotron now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return SyncReplicationHandler(self)
-
-    def build_presence_handler(self):
-        return SynchrotronPresence(self)
-
-    def build_typing_handler(self):
-        return SynchrotronTyping(self)
-
-
-class SyncReplicationHandler(ReplicationClientHandler):
-    def __init__(self, hs):
-        super(SyncReplicationHandler, self).__init__(hs.get_datastore())
-
-        self.store = hs.get_datastore()
-        self.typing_handler = hs.get_typing_handler()
-        # NB this is a SynchrotronPresence, not a normal PresenceHandler
-        self.presence_handler = hs.get_presence_handler()
-        self.notifier = hs.get_notifier()
-
-    async def on_rdata(self, stream_name, token, rows):
-        await super(SyncReplicationHandler, self).on_rdata(stream_name, token, rows)
-        run_in_background(self.process_and_notify, stream_name, token, rows)
-
-    def get_streams_to_replicate(self):
-        args = super(SyncReplicationHandler, self).get_streams_to_replicate()
-        args.update(self.typing_handler.stream_positions())
-        return args
-
-    def get_currently_syncing_users(self):
-        return self.presence_handler.get_currently_syncing_users()
-
-    async def process_and_notify(self, stream_name, token, rows):
-        try:
-            if stream_name == "events":
-                # We shouldn't get multiple rows per token for events stream, so
-                # we don't need to optimise this for multiple rows.
-                for row in rows:
-                    if row.type != EventsStreamEventRow.TypeId:
-                        continue
-                    assert isinstance(row, EventsStreamRow)
-
-                    event = await self.store.get_event(
-                        row.data.event_id, allow_rejected=True
-                    )
-                    if event.rejected_reason:
-                        continue
-
-                    extra_users = ()
-                    if event.type == EventTypes.Member:
-                        extra_users = (event.state_key,)
-                    max_token = self.store.get_room_max_stream_ordering()
-                    self.notifier.on_new_room_event(
-                        event, token, max_token, extra_users
-                    )
-            elif stream_name == "push_rules":
-                self.notifier.on_new_event(
-                    "push_rules_key", token, users=[row.user_id for row in rows]
-                )
-            elif stream_name in ("account_data", "tag_account_data"):
-                self.notifier.on_new_event(
-                    "account_data_key", token, users=[row.user_id for row in rows]
-                )
-            elif stream_name == "receipts":
-                self.notifier.on_new_event(
-                    "receipt_key", token, rooms=[row.room_id for row in rows]
-                )
-            elif stream_name == "typing":
-                self.typing_handler.process_replication_rows(token, rows)
-                self.notifier.on_new_event(
-                    "typing_key", token, rooms=[row.room_id for row in rows]
-                )
-            elif stream_name == "to_device":
-                entities = [row.entity for row in rows if row.entity.startswith("@")]
-                if entities:
-                    self.notifier.on_new_event("to_device_key", token, users=entities)
-            elif stream_name == "device_lists":
-                all_room_ids = set()
-                for row in rows:
-                    room_ids = await self.store.get_rooms_for_user(row.user_id)
-                    all_room_ids.update(room_ids)
-                self.notifier.on_new_event("device_list_key", token, rooms=all_room_ids)
-            elif stream_name == "presence":
-                await self.presence_handler.process_replication_rows(token, rows)
-            elif stream_name == "receipts":
-                self.notifier.on_new_event(
-                    "groups_key", token, users=[row.user_id for row in rows]
-                )
-        except Exception:
-            logger.exception("Error processing replication")
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config("Synapse synchrotron", config_options)
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.synchrotron"
-
-    synapse.events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    ss = SynchrotronServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-        application_service_handler=SynchrotronApplicationService(),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-synchrotron", config)
+import sys
 
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/app/user_dir.py b/synapse/app/user_dir.py
index ba536d6f04..503d44f687 100644
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@@ -14,217 +14,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-import logging
 import sys
 
-from twisted.internet import defer, reactor
-from twisted.web.resource import NoResource
-
-import synapse
-from synapse import events
-from synapse.app import _base
-from synapse.config._base import ConfigError
-from synapse.config.homeserver import HomeServerConfig
-from synapse.config.logger import setup_logging
-from synapse.http.server import JsonResource
-from synapse.http.site import SynapseSite
-from synapse.logging.context import LoggingContext, run_in_background
-from synapse.metrics import METRICS_PREFIX, MetricsResource, RegistryProxy
-from synapse.replication.slave.storage._base import BaseSlavedStore
-from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
-from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
-from synapse.replication.slave.storage.events import SlavedEventStore
-from synapse.replication.slave.storage.registration import SlavedRegistrationStore
-from synapse.replication.tcp.client import ReplicationClientHandler
-from synapse.replication.tcp.streams.events import (
-    EventsStream,
-    EventsStreamCurrentStateRow,
-)
-from synapse.rest.client.v2_alpha import user_directory
-from synapse.server import HomeServer
-from synapse.storage.data_stores.main.user_directory import UserDirectoryStore
-from synapse.storage.database import Database
-from synapse.util.caches.stream_change_cache import StreamChangeCache
-from synapse.util.httpresourcetree import create_resource_tree
-from synapse.util.manhole import manhole
-from synapse.util.versionstring import get_version_string
-
-logger = logging.getLogger("synapse.app.user_dir")
-
-
-class UserDirectorySlaveStore(
-    SlavedEventStore,
-    SlavedApplicationServiceStore,
-    SlavedRegistrationStore,
-    SlavedClientIpStore,
-    UserDirectoryStore,
-    BaseSlavedStore,
-):
-    def __init__(self, database: Database, db_conn, hs):
-        super(UserDirectorySlaveStore, 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(
-            db_conn,
-            "current_state_delta_stream",
-            entity_column="room_id",
-            stream_column="stream_id",
-            max_value=events_max,  # As we share the stream id with events token
-            limit=1000,
-        )
-        self._curr_state_delta_stream_cache = StreamChangeCache(
-            "_curr_state_delta_stream_cache",
-            min_curr_state_delta_id,
-            prefilled_cache=curr_state_delta_prefill,
-        )
-
-    def stream_positions(self):
-        result = super(UserDirectorySlaveStore, self).stream_positions()
-        return result
-
-    def process_replication_rows(self, stream_name, token, rows):
-        if stream_name == EventsStream.NAME:
-            self._stream_id_gen.advance(token)
-            for row in rows:
-                if row.type != EventsStreamCurrentStateRow.TypeId:
-                    continue
-                self._curr_state_delta_stream_cache.entity_has_changed(
-                    row.data.room_id, token
-                )
-        return super(UserDirectorySlaveStore, self).process_replication_rows(
-            stream_name, token, rows
-        )
-
-
-class UserDirectoryServer(HomeServer):
-    DATASTORE_CLASS = UserDirectorySlaveStore
-
-    def _listen_http(self, listener_config):
-        port = listener_config["port"]
-        bind_addresses = listener_config["bind_addresses"]
-        site_tag = listener_config.get("tag", port)
-        resources = {}
-        for res in listener_config["resources"]:
-            for name in res["names"]:
-                if name == "metrics":
-                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
-                elif name == "client":
-                    resource = JsonResource(self, canonical_json=False)
-                    user_directory.register_servlets(self, resource)
-                    resources.update(
-                        {
-                            "/_matrix/client/r0": resource,
-                            "/_matrix/client/unstable": resource,
-                            "/_matrix/client/v2_alpha": resource,
-                            "/_matrix/client/api/v1": resource,
-                        }
-                    )
-
-        root_resource = create_resource_tree(resources, NoResource())
-
-        _base.listen_tcp(
-            bind_addresses,
-            port,
-            SynapseSite(
-                "synapse.access.http.%s" % (site_tag,),
-                site_tag,
-                listener_config,
-                root_resource,
-                self.version_string,
-            ),
-        )
-
-        logger.info("Synapse user_dir now listening on port %d", port)
-
-    def start_listening(self, listeners):
-        for listener in listeners:
-            if listener["type"] == "http":
-                self._listen_http(listener)
-            elif listener["type"] == "manhole":
-                _base.listen_tcp(
-                    listener["bind_addresses"],
-                    listener["port"],
-                    manhole(
-                        username="matrix", password="rabbithole", globals={"hs": self}
-                    ),
-                )
-            elif listener["type"] == "metrics":
-                if not self.get_config().enable_metrics:
-                    logger.warning(
-                        (
-                            "Metrics listener configured, but "
-                            "enable_metrics is not True!"
-                        )
-                    )
-                else:
-                    _base.listen_metrics(listener["bind_addresses"], listener["port"])
-            else:
-                logger.warning("Unrecognized listener type: %s", listener["type"])
-
-        self.get_tcp_replication().start_replication(self)
-
-    def build_tcp_replication(self):
-        return UserDirectoryReplicationHandler(self)
-
-
-class UserDirectoryReplicationHandler(ReplicationClientHandler):
-    def __init__(self, hs):
-        super(UserDirectoryReplicationHandler, self).__init__(hs.get_datastore())
-        self.user_directory = hs.get_user_directory_handler()
-
-    async def on_rdata(self, stream_name, token, rows):
-        await super(UserDirectoryReplicationHandler, self).on_rdata(
-            stream_name, token, rows
-        )
-        if stream_name == EventsStream.NAME:
-            run_in_background(self._notify_directory)
-
-    @defer.inlineCallbacks
-    def _notify_directory(self):
-        try:
-            yield self.user_directory.notify_new_event()
-        except Exception:
-            logger.exception("Error notifiying user directory of state update")
-
-
-def start(config_options):
-    try:
-        config = HomeServerConfig.load_config("Synapse user directory", config_options)
-    except ConfigError as e:
-        sys.stderr.write("\n" + str(e) + "\n")
-        sys.exit(1)
-
-    assert config.worker_app == "synapse.app.user_dir"
-
-    events.USE_FROZEN_DICTS = config.use_frozen_dicts
-
-    if config.update_user_directory:
-        sys.stderr.write(
-            "\nThe update_user_directory must be disabled in the main synapse process"
-            "\nbefore they can be run in a separate worker."
-            "\nPlease add ``update_user_directory: false`` to the main config"
-            "\n"
-        )
-        sys.exit(1)
-
-    # Force the pushers to start since they will be disabled in the main config
-    config.update_user_directory = True
-
-    ss = UserDirectoryServer(
-        config.server_name,
-        config=config,
-        version_string="Synapse/" + get_version_string(synapse),
-    )
-
-    setup_logging(ss, config, use_worker_options=True)
-
-    ss.setup()
-    reactor.addSystemEventTrigger(
-        "before", "startup", _base.start, ss, config.worker_listeners
-    )
-
-    _base.start_worker_reactor("synapse-user-dir", config)
-
+from synapse.app.generic_worker import start
+from synapse.util.logcontext import LoggingContext
 
 if __name__ == "__main__":
     with LoggingContext("main"):
diff --git a/synapse/config/emailconfig.py b/synapse/config/emailconfig.py
index 74853f9faa..f31fc85ec8 100644
--- a/synapse/config/emailconfig.py
+++ b/synapse/config/emailconfig.py
@@ -27,6 +27,12 @@ import pkg_resources
 
 from ._base import Config, ConfigError
 
+MISSING_PASSWORD_RESET_CONFIG_ERROR = """\
+Password reset emails are enabled on this homeserver due to a partial
+'email' block. However, the following required keys are missing:
+    %s
+"""
+
 
 class EmailConfig(Config):
     section = "email"
@@ -142,24 +148,18 @@ class EmailConfig(Config):
             bleach
 
         if self.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
-            required = ["smtp_host", "smtp_port", "notif_from"]
-
             missing = []
-            for k in required:
-                if k not in email_config:
-                    missing.append("email." + k)
+            if not self.email_notif_from:
+                missing.append("email.notif_from")
 
             # public_baseurl is required to build password reset and validation links that
             # will be emailed to users
             if config.get("public_baseurl") is None:
                 missing.append("public_baseurl")
 
-            if len(missing) > 0:
-                raise RuntimeError(
-                    "Password resets emails are configured to be sent from "
-                    "this homeserver due to a partial 'email' block. "
-                    "However, the following required keys are missing: %s"
-                    % (", ".join(missing),)
+            if missing:
+                raise ConfigError(
+                    MISSING_PASSWORD_RESET_CONFIG_ERROR % (", ".join(missing),)
                 )
 
             # These email templates have placeholders in them, and thus must be
@@ -245,32 +245,25 @@ class EmailConfig(Config):
             )
 
         if self.email_enable_notifs:
-            required = [
-                "smtp_host",
-                "smtp_port",
-                "notif_from",
-                "notif_template_html",
-                "notif_template_text",
-            ]
-
             missing = []
-            for k in required:
-                if k not in email_config:
-                    missing.append(k)
-
-            if len(missing) > 0:
-                raise RuntimeError(
-                    "email.enable_notifs is True but required keys are missing: %s"
-                    % (", ".join(["email." + k for k in missing]),)
-                )
+            if not self.email_notif_from:
+                missing.append("email.notif_from")
 
             if config.get("public_baseurl") is None:
-                raise RuntimeError(
-                    "email.enable_notifs is True but no public_baseurl is set"
+                missing.append("public_baseurl")
+
+            if missing:
+                raise ConfigError(
+                    "email.enable_notifs is True but required keys are missing: %s"
+                    % (", ".join(missing),)
                 )
 
-            self.email_notif_template_html = email_config["notif_template_html"]
-            self.email_notif_template_text = email_config["notif_template_text"]
+            self.email_notif_template_html = email_config.get(
+                "notif_template_html", "notif_mail.html"
+            )
+            self.email_notif_template_text = email_config.get(
+                "notif_template_text", "notif_mail.txt"
+            )
 
             for f in self.email_notif_template_text, self.email_notif_template_html:
                 p = os.path.join(self.email_template_dir, f)
@@ -323,10 +316,6 @@ class EmailConfig(Config):
           #
           #require_transport_security: true
 
-          # Enable sending emails for messages that the user has missed
-          #
-          #enable_notifs: false
-
           # notif_from defines the "From" address to use when sending emails.
           # It must be set if email sending is enabled.
           #
@@ -344,6 +333,11 @@ class EmailConfig(Config):
           #
           #app_name: my_branded_matrix_server
 
+          # Uncomment the following to enable sending emails for messages that the user
+          # has missed. Disabled by default.
+          #
+          #enable_notifs: true
+
           # Uncomment the following to disable automatic subscription to email
           # notifications for new users. Enabled by default.
           #
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 0ec1b0fadd..7525765fee 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -1066,12 +1066,12 @@ KNOWN_RESOURCES = (
 
 
 def _check_resource_config(listeners):
-    resource_names = set(
+    resource_names = {
         res_name
         for listener in listeners
         for res in listener.get("resources", [])
         for res_name in res.get("names", [])
-    )
+    }
 
     for resource in resource_names:
         if resource not in KNOWN_RESOURCES:
diff --git a/synapse/config/tls.py b/synapse/config/tls.py
index 2514b0713d..a65538562b 100644
--- a/synapse/config/tls.py
+++ b/synapse/config/tls.py
@@ -32,6 +32,17 @@ from synapse.util import glob_to_regex
 
 logger = logging.getLogger(__name__)
 
+ACME_SUPPORT_ENABLED_WARN = """\
+This server uses Synapse's built-in ACME support. Note that ACME v1 has been
+deprecated by Let's Encrypt, and that Synapse doesn't currently support ACME v2,
+which means that this feature will not work with Synapse installs set up after
+November 2019, and that it may stop working on June 2020 for installs set up
+before that date.
+
+For more info and alternative solutions, see
+https://github.com/matrix-org/synapse/blob/master/docs/ACME.md#deprecation-of-acme-v1
+--------------------------------------------------------------------------------"""
+
 
 class TlsConfig(Config):
     section = "tls"
@@ -44,6 +55,9 @@ class TlsConfig(Config):
 
         self.acme_enabled = acme_config.get("enabled", False)
 
+        if self.acme_enabled:
+            logger.warning(ACME_SUPPORT_ENABLED_WARN)
+
         # hyperlink complains on py2 if this is not a Unicode
         self.acme_url = six.text_type(
             acme_config.get("url", "https://acme-v01.api.letsencrypt.org/directory")
@@ -246,7 +260,7 @@ class TlsConfig(Config):
                 crypto.FILETYPE_ASN1, self.tls_certificate
             )
             sha256_fingerprint = encode_base64(sha256(x509_certificate_bytes).digest())
-            sha256_fingerprints = set(f["sha256"] for f in self.tls_fingerprints)
+            sha256_fingerprints = {f["sha256"] for f in self.tls_fingerprints}
             if sha256_fingerprint not in sha256_fingerprints:
                 self.tls_fingerprints.append({"sha256": sha256_fingerprint})
 
@@ -362,6 +376,11 @@ class TlsConfig(Config):
         # ACME support: This will configure Synapse to request a valid TLS certificate
         # for your configured `server_name` via Let's Encrypt.
         #
+        # Note that ACME v1 is now deprecated, and Synapse currently doesn't support
+        # ACME v2. This means that this feature currently won't work with installs set
+        # up after November 2019. For more info, and alternative solutions, see
+        # https://github.com/matrix-org/synapse/blob/master/docs/ACME.md#deprecation-of-acme-v1
+        #
         # Note that provisioning a certificate in this way requires port 80 to be
         # routed to Synapse so that it can complete the http-01 ACME challenge.
         # By default, if you enable ACME support, Synapse will attempt to listen on
diff --git a/synapse/crypto/keyring.py b/synapse/crypto/keyring.py
index 6fe5a6a26a..983f0ead8c 100644
--- a/synapse/crypto/keyring.py
+++ b/synapse/crypto/keyring.py
@@ -326,9 +326,7 @@ class Keyring(object):
             verify_requests (list[VerifyJsonRequest]): list of verify requests
         """
 
-        remaining_requests = set(
-            (rq for rq in verify_requests if not rq.key_ready.called)
-        )
+        remaining_requests = {rq for rq in verify_requests if not rq.key_ready.called}
 
         @defer.inlineCallbacks
         def do_iterations():
@@ -396,7 +394,7 @@ class Keyring(object):
 
         results = yield fetcher.get_keys(missing_keys)
 
-        completed = list()
+        completed = []
         for verify_request in remaining_requests:
             server_name = verify_request.server_name
 
diff --git a/synapse/events/__init__.py b/synapse/events/__init__.py
index a842661a90..7307116556 100644
--- a/synapse/events/__init__.py
+++ b/synapse/events/__init__.py
@@ -1,6 +1,7 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
 # Copyright 2019 New Vector Ltd
+# Copyright 2020 The Matrix.org Foundation C.I.C.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -37,34 +38,115 @@ from synapse.util.frozenutils import freeze
 USE_FROZEN_DICTS = strtobool(os.environ.get("SYNAPSE_USE_FROZEN_DICTS", "0"))
 
 
+class DictProperty:
+    """An object property which delegates to the `_dict` within its parent object."""
+
+    __slots__ = ["key"]
+
+    def __init__(self, key: str):
+        self.key = key
+
+    def __get__(self, instance, owner=None):
+        # if the property is accessed as a class property rather than an instance
+        # property, return the property itself rather than the value
+        if instance is None:
+            return self
+        try:
+            return instance._dict[self.key]
+        except KeyError as e1:
+            # We want this to look like a regular attribute error (mostly so that
+            # hasattr() works correctly), so we convert the KeyError into an
+            # AttributeError.
+            #
+            # To exclude the KeyError from the traceback, we explicitly
+            # 'raise from e1.__context__' (which is better than 'raise from None',
+            # becuase that would omit any *earlier* exceptions).
+            #
+            raise AttributeError(
+                "'%s' has no '%s' property" % (type(instance), self.key)
+            ) from e1.__context__
+
+    def __set__(self, instance, v):
+        instance._dict[self.key] = v
+
+    def __delete__(self, instance):
+        try:
+            del instance._dict[self.key]
+        except KeyError as e1:
+            raise AttributeError(
+                "'%s' has no '%s' property" % (type(instance), self.key)
+            ) from e1.__context__
+
+
+class DefaultDictProperty(DictProperty):
+    """An extension of DictProperty which provides a default if the property is
+    not present in the parent's _dict.
+
+    Note that this means that hasattr() on the property always returns True.
+    """
+
+    __slots__ = ["default"]
+
+    def __init__(self, key, default):
+        super().__init__(key)
+        self.default = default
+
+    def __get__(self, instance, owner=None):
+        if instance is None:
+            return self
+        return instance._dict.get(self.key, self.default)
+
+
 class _EventInternalMetadata(object):
-    def __init__(self, internal_metadata_dict):
-        self.__dict__ = dict(internal_metadata_dict)
+    __slots__ = ["_dict"]
+
+    def __init__(self, internal_metadata_dict: JsonDict):
+        # we have to copy the dict, because it turns out that the same dict is
+        # reused. TODO: fix that
+        self._dict = dict(internal_metadata_dict)
+
+    outlier = DictProperty("outlier")  # type: bool
+    out_of_band_membership = DictProperty("out_of_band_membership")  # type: bool
+    send_on_behalf_of = DictProperty("send_on_behalf_of")  # type: str
+    recheck_redaction = DictProperty("recheck_redaction")  # type: bool
+    soft_failed = DictProperty("soft_failed")  # type: bool
+    proactively_send = DictProperty("proactively_send")  # type: bool
+    redacted = DictProperty("redacted")  # type: bool
+    txn_id = DictProperty("txn_id")  # type: str
+    token_id = DictProperty("token_id")  # type: str
+    stream_ordering = DictProperty("stream_ordering")  # type: int
+
+    # XXX: These are set by StreamWorkerStore._set_before_and_after.
+    # I'm pretty sure that these are never persisted to the database, so shouldn't
+    # be here
+    before = DictProperty("before")  # type: str
+    after = DictProperty("after")  # type: str
+    order = DictProperty("order")  # type: int
 
-    def get_dict(self):
-        return dict(self.__dict__)
+    def get_dict(self) -> JsonDict:
+        return dict(self._dict)
 
-    def is_outlier(self):
-        return getattr(self, "outlier", False)
+    def is_outlier(self) -> bool:
+        return self._dict.get("outlier", False)
 
-    def is_out_of_band_membership(self):
+    def is_out_of_band_membership(self) -> bool:
         """Whether this is an out of band membership, like an invite or an invite
         rejection. This is needed as those events are marked as outliers, but
         they still need to be processed as if they're new events (e.g. updating
         invite state in the database, relaying to clients, etc).
         """
-        return getattr(self, "out_of_band_membership", False)
+        return self._dict.get("out_of_band_membership", False)
 
-    def get_send_on_behalf_of(self):
+    def get_send_on_behalf_of(self) -> Optional[str]:
         """Whether this server should send the event on behalf of another server.
         This is used by the federation "send_join" API to forward the initial join
         event for a server in the room.
 
         returns a str with the name of the server this event is sent on behalf of.
         """
-        return getattr(self, "send_on_behalf_of", None)
+        return self._dict.get("send_on_behalf_of")
 
-    def need_to_check_redaction(self):
+    def need_to_check_redaction(self) -> bool:
         """Whether the redaction event needs to be rechecked when fetching
         from the database.
 
@@ -77,9 +159,9 @@ class _EventInternalMetadata(object):
         Returns:
             bool
         """
-        return getattr(self, "recheck_redaction", False)
+        return self._dict.get("recheck_redaction", False)
 
-    def is_soft_failed(self):
+    def is_soft_failed(self) -> bool:
         """Whether the event has been soft failed.
 
         Soft failed events should be handled as usual, except:
@@ -91,7 +173,7 @@ class _EventInternalMetadata(object):
         Returns:
             bool
         """
-        return getattr(self, "soft_failed", False)
+        return self._dict.get("soft_failed", False)
 
     def should_proactively_send(self):
         """Whether the event, if ours, should be sent to other clients and
@@ -103,7 +185,7 @@ class _EventInternalMetadata(object):
         Returns:
             bool
         """
-        return getattr(self, "proactively_send", True)
+        return self._dict.get("proactively_send", True)
 
     def is_redacted(self):
         """Whether the event has been redacted.
@@ -114,52 +196,7 @@ class _EventInternalMetadata(object):
         Returns:
             bool
         """
-        return getattr(self, "redacted", False)
-
-
-_SENTINEL = object()
-
-
-def _event_dict_property(key, default=_SENTINEL):
-    """Creates a new property for the given key that delegates access to
-    `self._event_dict`.
-
-    The default is used if the key is missing from the `_event_dict`, if given,
-    otherwise an AttributeError will be raised.
-
-    Note: If a default is given then `hasattr` will always return true.
-    """
-
-    # We want to be able to use hasattr with the event dict properties.
-    # However, (on python3) hasattr expects AttributeError to be raised. Hence,
-    # we need to transform the KeyError into an AttributeError
-
-    def getter_raises(self):
-        try:
-            return self._event_dict[key]
-        except KeyError:
-            raise AttributeError(key)
-
-    def getter_default(self):
-        return self._event_dict.get(key, default)
-
-    def setter(self, v):
-        try:
-            self._event_dict[key] = v
-        except KeyError:
-            raise AttributeError(key)
-
-    def delete(self):
-        try:
-            del self._event_dict[key]
-        except KeyError:
-            raise AttributeError(key)
-
-    if default is _SENTINEL:
-        # No default given, so use the getter that raises
-        return property(getter_raises, setter, delete)
-    else:
-        return property(getter_default, setter, delete)
+        return self._dict.get("redacted", False)
 
 
 class EventBase(object):
@@ -175,23 +212,23 @@ class EventBase(object):
         self.unsigned = unsigned
         self.rejected_reason = rejected_reason
 
-        self._event_dict = event_dict
+        self._dict = event_dict
 
         self.internal_metadata = _EventInternalMetadata(internal_metadata_dict)
 
-    auth_events = _event_dict_property("auth_events")
-    depth = _event_dict_property("depth")
-    content = _event_dict_property("content")
-    hashes = _event_dict_property("hashes")
-    origin = _event_dict_property("origin")
-    origin_server_ts = _event_dict_property("origin_server_ts")
-    prev_events = _event_dict_property("prev_events")
-    redacts = _event_dict_property("redacts", None)
-    room_id = _event_dict_property("room_id")
-    sender = _event_dict_property("sender")
-    state_key = _event_dict_property("state_key")
-    type = _event_dict_property("type")
-    user_id = _event_dict_property("sender")
+    auth_events = DictProperty("auth_events")
+    depth = DictProperty("depth")
+    content = DictProperty("content")
+    hashes = DictProperty("hashes")
+    origin = DictProperty("origin")
+    origin_server_ts = DictProperty("origin_server_ts")
+    prev_events = DictProperty("prev_events")
+    redacts = DefaultDictProperty("redacts", None)
+    room_id = DictProperty("room_id")
+    sender = DictProperty("sender")
+    state_key = DictProperty("state_key")
+    type = DictProperty("type")
+    user_id = DictProperty("sender")
 
     @property
     def event_id(self) -> str:
@@ -205,13 +242,13 @@ class EventBase(object):
         return hasattr(self, "state_key") and self.state_key is not None
 
     def get_dict(self) -> JsonDict:
-        d = dict(self._event_dict)
+        d = dict(self._dict)
         d.update({"signatures": self.signatures, "unsigned": dict(self.unsigned)})
 
         return d
 
     def get(self, key, default=None):
-        return self._event_dict.get(key, default)
+        return self._dict.get(key, default)
 
     def get_internal_metadata_dict(self):
         return self.internal_metadata.get_dict()
@@ -233,16 +270,16 @@ class EventBase(object):
         raise AttributeError("Unrecognized attribute %s" % (instance,))
 
     def __getitem__(self, field):
-        return self._event_dict[field]
+        return self._dict[field]
 
     def __contains__(self, field):
-        return field in self._event_dict
+        return field in self._dict
 
     def items(self):
-        return list(self._event_dict.items())
+        return list(self._dict.items())
 
     def keys(self):
-        return six.iterkeys(self._event_dict)
+        return six.iterkeys(self._dict)
 
     def prev_event_ids(self):
         """Returns the list of prev event IDs. The order matches the order
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 001bb304ae..876fb0e245 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -129,9 +129,9 @@ class FederationRemoteSendQueue(object):
             for key in keys[:i]:
                 del self.presence_changed[key]
 
-            user_ids = set(
+            user_ids = {
                 user_id for uids in self.presence_changed.values() for user_id in uids
-            )
+            }
 
             keys = self.presence_destinations.keys()
             i = self.presence_destinations.bisect_left(position_to_delete)
diff --git a/synapse/groups/groups_server.py b/synapse/groups/groups_server.py
index c106abae21..4f0dc0a209 100644
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -608,7 +608,7 @@ class GroupsServerHandler(GroupsServerWorkerHandler):
         user_results = yield self.store.get_users_in_group(
             group_id, include_private=True
         )
-        if user_id in [user_result["user_id"] for user_result in user_results]:
+        if user_id in (user_result["user_id"] for user_result in user_results):
             raise SynapseError(400, "User already in group")
 
         content = {
diff --git a/synapse/handlers/acme.py b/synapse/handlers/acme.py
index 46ac73106d..a2d7959abe 100644
--- a/synapse/handlers/acme.py
+++ b/synapse/handlers/acme.py
@@ -25,6 +25,15 @@ from synapse.app import check_bind_error
 
 logger = logging.getLogger(__name__)
 
+ACME_REGISTER_FAIL_ERROR = """
+--------------------------------------------------------------------------------
+Failed to register with the ACME provider. This is likely happening because the installation
+is new, and ACME v1 has been deprecated by Let's Encrypt and disabled for
+new installations since November 2019.
+At the moment, Synapse doesn't support ACME v2. For more information and alternative
+solutions, please read https://github.com/matrix-org/synapse/blob/master/docs/ACME.md#deprecation-of-acme-v1
+--------------------------------------------------------------------------------"""
+
 
 class AcmeHandler(object):
     def __init__(self, hs):
@@ -71,7 +80,12 @@ class AcmeHandler(object):
         # want it to control where we save the certificates, we have to reach in
         # and trigger the registration machinery ourselves.
         self._issuer._registered = False
-        yield self._issuer._ensure_registered()
+
+        try:
+            yield self._issuer._ensure_registered()
+        except Exception:
+            logger.error(ACME_REGISTER_FAIL_ERROR)
+            raise
 
     @defer.inlineCallbacks
     def provision_certificate(self):
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 50cea3f378..a514c30714 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -742,6 +742,6 @@ class DeviceListUpdater(object):
 
         # We clobber the seen updates since we've re-synced from a given
         # point.
-        self._seen_updates[user_id] = set([stream_id])
+        self._seen_updates[user_id] = {stream_id}
 
         defer.returnValue(result)
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 8c5980cb0c..0b23ca919a 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -14,8 +14,10 @@
 # limitations under the License.
 
 
+import collections
 import logging
 import string
+from typing import List
 
 from twisted.internet import defer
 
@@ -28,7 +30,7 @@ from synapse.api.errors import (
     StoreError,
     SynapseError,
 )
-from synapse.types import RoomAlias, UserID, get_domain_from_id
+from synapse.types import Requester, RoomAlias, UserID, get_domain_from_id
 
 from ._base import BaseHandler
 
@@ -70,7 +72,7 @@ class DirectoryHandler(BaseHandler):
         # TODO(erikj): Check if there is a current association.
         if not servers:
             users = yield self.state.get_current_users_in_room(room_id)
-            servers = set(get_domain_from_id(u) for u in users)
+            servers = {get_domain_from_id(u) for u in users}
 
         if not servers:
             raise SynapseError(400, "Failed to get server list")
@@ -81,13 +83,7 @@ class DirectoryHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def create_association(
-        self,
-        requester,
-        room_alias,
-        room_id,
-        servers=None,
-        send_event=True,
-        check_membership=True,
+        self, requester, room_alias, room_id, servers=None, check_membership=True,
     ):
         """Attempt to create a new alias
 
@@ -97,7 +93,6 @@ class DirectoryHandler(BaseHandler):
             room_id (str)
             servers (list[str]|None): List of servers that others servers
                 should try and join via
-            send_event (bool): Whether to send an updated m.room.aliases event
             check_membership (bool): Whether to check if the user is in the room
                 before the alias can be set (if the server's config requires it).
 
@@ -150,16 +145,9 @@ class DirectoryHandler(BaseHandler):
                 )
 
         yield self._create_association(room_alias, room_id, servers, creator=user_id)
-        if send_event:
-            try:
-                yield self.send_room_alias_update_event(requester, room_id)
-            except AuthError as e:
-                # sending the aliases event may fail due to the user not having
-                # permission in the room; this is permitted.
-                logger.info("Skipping updating aliases event due to auth error %s", e)
 
     @defer.inlineCallbacks
-    def delete_association(self, requester, room_alias, send_event=True):
+    def delete_association(self, requester, room_alias):
         """Remove an alias from the directory
 
         (this is only meant for human users; AS users should call
@@ -168,9 +156,6 @@ class DirectoryHandler(BaseHandler):
         Args:
             requester (Requester):
             room_alias (RoomAlias):
-            send_event (bool): Whether to send an updated m.room.aliases event.
-                Note that, if we delete the canonical alias, we will always attempt
-                to send an m.room.canonical_alias event
 
         Returns:
             Deferred[unicode]: room id that the alias used to point to
@@ -206,9 +191,6 @@ class DirectoryHandler(BaseHandler):
         room_id = yield self._delete_association(room_alias)
 
         try:
-            if send_event:
-                yield self.send_room_alias_update_event(requester, room_id)
-
             yield self._update_canonical_alias(
                 requester, requester.user.to_string(), room_id, room_alias
             )
@@ -273,7 +255,7 @@ class DirectoryHandler(BaseHandler):
             )
 
         users = yield self.state.get_current_users_in_room(room_id)
-        extra_servers = set(get_domain_from_id(u) for u in users)
+        extra_servers = {get_domain_from_id(u) for u in users}
         servers = set(extra_servers) | set(servers)
 
         # If this server is in the list of servers, return it first.
@@ -302,42 +284,51 @@ class DirectoryHandler(BaseHandler):
             )
 
     @defer.inlineCallbacks
-    def send_room_alias_update_event(self, requester, room_id):
-        aliases = yield self.store.get_aliases_for_room(room_id)
-
-        yield self.event_creation_handler.create_and_send_nonmember_event(
-            requester,
-            {
-                "type": EventTypes.Aliases,
-                "state_key": self.hs.hostname,
-                "room_id": room_id,
-                "sender": requester.user.to_string(),
-                "content": {"aliases": aliases},
-            },
-            ratelimit=False,
-        )
-
-    @defer.inlineCallbacks
     def _update_canonical_alias(self, requester, user_id, room_id, room_alias):
+        """
+        Send an updated canonical alias event if the removed alias was set as
+        the canonical alias or listed in the alt_aliases field.
+        """
         alias_event = yield self.state.get_current_state(
             room_id, EventTypes.CanonicalAlias, ""
         )
 
-        alias_str = room_alias.to_string()
-        if not alias_event or alias_event.content.get("alias", "") != alias_str:
+        # There is no canonical alias, nothing to do.
+        if not alias_event:
             return
 
-        yield self.event_creation_handler.create_and_send_nonmember_event(
-            requester,
-            {
-                "type": EventTypes.CanonicalAlias,
-                "state_key": "",
-                "room_id": room_id,
-                "sender": user_id,
-                "content": {},
-            },
-            ratelimit=False,
-        )
+        # Obtain a mutable version of the event content.
+        content = dict(alias_event.content)
+        send_update = False
+
+        # Remove the alias property if it matches the removed alias.
+        alias_str = room_alias.to_string()
+        if alias_event.content.get("alias", "") == alias_str:
+            send_update = True
+            content.pop("alias", "")
+
+        # Filter alt_aliases for the removed alias.
+        alt_aliases = content.pop("alt_aliases", None)
+        # If the aliases are not a list (or not found) do not attempt to modify
+        # the list.
+        if isinstance(alt_aliases, collections.Sequence):
+            send_update = True
+            alt_aliases = [alias for alias in alt_aliases if alias != alias_str]
+            if alt_aliases:
+                content["alt_aliases"] = alt_aliases
+
+        if send_update:
+            yield self.event_creation_handler.create_and_send_nonmember_event(
+                requester,
+                {
+                    "type": EventTypes.CanonicalAlias,
+                    "state_key": "",
+                    "room_id": room_id,
+                    "sender": user_id,
+                    "content": content,
+                },
+                ratelimit=False,
+            )
 
     @defer.inlineCallbacks
     def get_association_from_room_alias(self, room_alias):
@@ -447,3 +438,19 @@ class DirectoryHandler(BaseHandler):
         yield self.store.set_room_is_public_appservice(
             room_id, appservice_id, network_id, visibility == "public"
         )
+
+    async def get_aliases_for_room(
+        self, requester: Requester, room_id: str
+    ) -> List[str]:
+        """
+        Get a list of the aliases that currently point to this room on this server
+        """
+        # allow access to server admins and current members of the room
+        is_admin = await self.auth.is_server_admin(requester.user)
+        if not is_admin:
+            await self.auth.check_user_in_room_or_world_readable(
+                room_id, requester.user.to_string()
+            )
+
+        aliases = await self.store.get_aliases_for_room(room_id)
+        return aliases
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index eb20ef4aec..38ab6a8fc3 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -41,7 +41,6 @@ from synapse.api.errors import (
     FederationDeniedError,
     FederationError,
     RequestSendFailed,
-    StoreError,
     SynapseError,
 )
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersion, RoomVersions
@@ -61,6 +60,7 @@ from synapse.replication.http.devices import ReplicationUserDevicesResyncRestSer
 from synapse.replication.http.federation import (
     ReplicationCleanRoomRestServlet,
     ReplicationFederationSendEventsRestServlet,
+    ReplicationStoreRoomOnInviteRestServlet,
 )
 from synapse.replication.http.membership import ReplicationUserJoinedLeftRoomRestServlet
 from synapse.state import StateResolutionStore, resolve_events_with_store
@@ -161,8 +161,12 @@ class FederationHandler(BaseHandler):
             self._user_device_resync = ReplicationUserDevicesResyncRestServlet.make_client(
                 hs
             )
+            self._maybe_store_room_on_invite = ReplicationStoreRoomOnInviteRestServlet.make_client(
+                hs
+            )
         else:
             self._device_list_updater = hs.get_device_handler().device_list_updater
+            self._maybe_store_room_on_invite = self.store.maybe_store_room_on_invite
 
         # When joining a room we need to queue any events for that room up
         self.room_queues = {}
@@ -659,11 +663,11 @@ class FederationHandler(BaseHandler):
         # this can happen if a remote server claims that the state or
         # auth_events at an event in room A are actually events in room B
 
-        bad_events = list(
+        bad_events = [
             (event_id, event.room_id)
             for event_id, event in fetched_events.items()
             if event.room_id != room_id
-        )
+        ]
 
         for bad_event_id, bad_room_id in bad_events:
             # This is a bogus situation, but since we may only discover it a long time
@@ -707,28 +711,6 @@ class FederationHandler(BaseHandler):
         except AuthError as e:
             raise FederationError("ERROR", e.code, e.msg, affected=event.event_id)
 
-        room = await self.store.get_room(room_id)
-
-        if not room:
-            try:
-                prev_state_ids = await context.get_prev_state_ids()
-                create_event = await self.store.get_event(
-                    prev_state_ids[(EventTypes.Create, "")]
-                )
-
-                room_version_id = create_event.content.get(
-                    "room_version", RoomVersions.V1.identifier
-                )
-
-                await self.store.store_room(
-                    room_id=room_id,
-                    room_creator_user_id="",
-                    is_public=False,
-                    room_version=KNOWN_ROOM_VERSIONS[room_version_id],
-                )
-            except StoreError:
-                logger.exception("Failed to store room.")
-
         if event.type == EventTypes.Member:
             if event.membership == Membership.JOIN:
                 # Only fire user_joined_room if the user has acutally
@@ -856,7 +838,7 @@ class FederationHandler(BaseHandler):
 
         # Don't bother processing events we already have.
         seen_events = await self.store.have_events_in_timeline(
-            set(e.event_id for e in events)
+            {e.event_id for e in events}
         )
 
         events = [e for e in events if e.event_id not in seen_events]
@@ -866,7 +848,7 @@ class FederationHandler(BaseHandler):
 
         event_map = {e.event_id: e for e in events}
 
-        event_ids = set(e.event_id for e in events)
+        event_ids = {e.event_id for e in events}
 
         # build a list of events whose prev_events weren't in the batch.
         # (XXX: this will include events whose prev_events we already have; that doesn't
@@ -892,13 +874,13 @@ class FederationHandler(BaseHandler):
             state_events.update({s.event_id: s for s in state})
             events_to_state[e_id] = state
 
-        required_auth = set(
+        required_auth = {
             a_id
             for event in events
             + list(state_events.values())
             + list(auth_events.values())
             for a_id in event.auth_event_ids()
-        )
+        }
         auth_events.update(
             {e_id: event_map[e_id] for e_id in required_auth if e_id in event_map}
         )
@@ -1247,7 +1229,7 @@ class FederationHandler(BaseHandler):
     async def on_event_auth(self, event_id: str) -> List[EventBase]:
         event = await self.store.get_event(event_id)
         auth = await self.store.get_auth_chain(
-            [auth_id for auth_id in event.auth_event_ids()], include_given=True
+            list(event.auth_event_ids()), include_given=True
         )
         return list(auth)
 
@@ -1323,16 +1305,18 @@ class FederationHandler(BaseHandler):
 
             logger.debug("do_invite_join event: %s", event)
 
-            try:
-                await self.store.store_room(
-                    room_id=room_id,
-                    room_creator_user_id="",
-                    is_public=False,
-                    room_version=room_version_obj,
-                )
-            except Exception:
-                # FIXME
-                pass
+            # if this is the first time we've joined this room, it's time to add
+            # a row to `rooms` with the correct room version. If there's already a
+            # row there, we should override it, since it may have been populated
+            # based on an invite request which lied about the room version.
+            #
+            # federation_client.send_join has already checked that the room
+            # version in the received create event is the same as room_version_obj,
+            # so we can rely on it now.
+            #
+            await self.store.upsert_room_on_join(
+                room_id=room_id, room_version=room_version_obj,
+            )
 
             await self._persist_auth_tree(
                 origin, auth_chain, state, event, room_version_obj
@@ -1558,6 +1542,13 @@ class FederationHandler(BaseHandler):
         if event.state_key == self._server_notices_mxid:
             raise SynapseError(http_client.FORBIDDEN, "Cannot invite this user")
 
+        # keep a record of the room version, if we don't yet know it.
+        # (this may get overwritten if we later get a different room version in a
+        # join dance).
+        await self._maybe_store_room_on_invite(
+            room_id=event.room_id, room_version=room_version
+        )
+
         event.internal_metadata.outlier = True
         event.internal_metadata.out_of_band_membership = True
 
@@ -2152,7 +2143,7 @@ class FederationHandler(BaseHandler):
 
         # Now get the current auth_chain for the event.
         local_auth_chain = await self.store.get_auth_chain(
-            [auth_id for auth_id in event.auth_event_ids()], include_given=True
+            list(event.auth_event_ids()), include_given=True
         )
 
         # TODO: Check if we would now reject event_id. If so we need to tell
@@ -2654,7 +2645,7 @@ class FederationHandler(BaseHandler):
             member_handler = self.hs.get_room_member_handler()
             yield member_handler.send_membership_event(None, event, context)
         else:
-            destinations = set(x.split(":", 1)[-1] for x in (sender_user_id, room_id))
+            destinations = {x.split(":", 1)[-1] for x in (sender_user_id, room_id)}
             yield self.federation_client.forward_third_party_invite(
                 destinations, room_id, event_dict
             )
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index 2e6755f19c..b116500c7d 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -18,7 +18,7 @@ import logging
 from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
-from synapse.api.errors import AuthError, Codes, SynapseError
+from synapse.api.errors import SynapseError
 from synapse.events.validator import EventValidator
 from synapse.handlers.presence import format_user_presence_state
 from synapse.logging.context import make_deferred_yieldable, run_in_background
@@ -274,8 +274,11 @@ class InitialSyncHandler(BaseHandler):
 
         user_id = requester.user.to_string()
 
-        membership, member_event_id = await self._check_in_room_or_world_readable(
-            room_id, user_id
+        (
+            membership,
+            member_event_id,
+        ) = await self.auth.check_user_in_room_or_world_readable(
+            room_id, user_id, allow_departed_users=True,
         )
         is_peeking = member_event_id is None
 
@@ -433,25 +436,3 @@ class InitialSyncHandler(BaseHandler):
             ret["membership"] = membership
 
         return ret
-
-    async def _check_in_room_or_world_readable(self, room_id, user_id):
-        try:
-            # check_user_was_in_room will return the most recent membership
-            # event for the user if:
-            #  * The user is a non-guest user, and was ever in the room
-            #  * The user is a guest user, and has joined the room
-            # else it will throw.
-            member_event = await self.auth.check_user_was_in_room(room_id, user_id)
-            return member_event.membership, member_event.event_id
-        except AuthError:
-            visibility = await self.state_handler.get_current_state(
-                room_id, EventTypes.RoomHistoryVisibility, ""
-            )
-            if (
-                visibility
-                and visibility.content["history_visibility"] == "world_readable"
-            ):
-                return Membership.JOIN, None
-            raise AuthError(
-                403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
-            )
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index be6ae18a92..a0103addd3 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -99,7 +99,9 @@ class MessageHandler(object):
         (
             membership,
             membership_event_id,
-        ) = yield self.auth.check_in_room_or_world_readable(room_id, user_id)
+        ) = yield self.auth.check_user_in_room_or_world_readable(
+            room_id, user_id, allow_departed_users=True
+        )
 
         if membership == Membership.JOIN:
             data = yield self.state.get_current_state(room_id, event_type, state_key)
@@ -177,7 +179,9 @@ class MessageHandler(object):
             (
                 membership,
                 membership_event_id,
-            ) = yield self.auth.check_in_room_or_world_readable(room_id, user_id)
+            ) = yield self.auth.check_user_in_room_or_world_readable(
+                room_id, user_id, allow_departed_users=True
+            )
 
             if membership == Membership.JOIN:
                 state_ids = yield self.store.get_filtered_current_state_ids(
@@ -216,8 +220,8 @@ class MessageHandler(object):
         if not requester.app_service:
             # We check AS auth after fetching the room membership, as it
             # requires us to pull out all joined members anyway.
-            membership, _ = yield self.auth.check_in_room_or_world_readable(
-                room_id, user_id
+            membership, _ = yield self.auth.check_user_in_room_or_world_readable(
+                room_id, user_id, allow_departed_users=True
             )
             if membership != Membership.JOIN:
                 raise NotImplementedError(
@@ -1012,11 +1016,10 @@ class EventCreationHandler(object):
             # matters as sometimes presence code can take a while.
             run_in_background(self._bump_active_time, requester.user)
 
-    @defer.inlineCallbacks
-    def _bump_active_time(self, user):
+    async def _bump_active_time(self, user):
         try:
             presence = self.hs.get_presence_handler()
-            yield presence.bump_presence_active_time(user)
+            await presence.bump_presence_active_time(user)
         except Exception:
             logger.exception("Error bumping presence active time")
 
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index caf841a643..d7442c62a7 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -133,7 +133,7 @@ class PaginationHandler(object):
             include_null = False
 
         logger.info(
-            "[purge] Running purge job for %d < max_lifetime <= %d (include NULLs = %s)",
+            "[purge] Running purge job for %s < max_lifetime <= %s (include NULLs = %s)",
             min_ms,
             max_ms,
             include_null,
@@ -335,7 +335,9 @@ class PaginationHandler(object):
             (
                 membership,
                 member_event_id,
-            ) = await self.auth.check_in_room_or_world_readable(room_id, user_id)
+            ) = await self.auth.check_user_in_room_or_world_readable(
+                room_id, user_id, allow_departed_users=True
+            )
 
             if source_config.direction == "b":
                 # if we're going backwards, we might need to backfill. This
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 202aa9294f..5526015ddb 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -24,11 +24,12 @@ The methods that define policy are:
 
 import logging
 from contextlib import contextmanager
-from typing import Dict, Set
+from typing import Dict, List, Set
 
 from six import iteritems, itervalues
 
 from prometheus_client import Counter
+from typing_extensions import ContextManager
 
 from twisted.internet import defer
 
@@ -42,10 +43,14 @@ from synapse.metrics.background_process_metrics import run_as_background_process
 from synapse.storage.presence import UserPresenceState
 from synapse.types import UserID, get_domain_from_id
 from synapse.util.async_helpers import Linearizer
-from synapse.util.caches.descriptors import cachedInlineCallbacks
+from synapse.util.caches.descriptors import cached
 from synapse.util.metrics import Measure
 from synapse.util.wheel_timer import WheelTimer
 
+MYPY = False
+if MYPY:
+    import synapse.server
+
 logger = logging.getLogger(__name__)
 
 
@@ -97,7 +102,6 @@ assert LAST_ACTIVE_GRANULARITY < IDLE_TIMER
 class PresenceHandler(object):
     def __init__(self, hs: "synapse.server.HomeServer"):
         self.hs = hs
-        self.is_mine = hs.is_mine
         self.is_mine_id = hs.is_mine_id
         self.server_name = hs.hostname
         self.clock = hs.get_clock()
@@ -150,7 +154,7 @@ class PresenceHandler(object):
 
         # Set of users who have presence in the `user_to_current_state` that
         # have not yet been persisted
-        self.unpersisted_users_changes = set()
+        self.unpersisted_users_changes = set()  # type: Set[str]
 
         hs.get_reactor().addSystemEventTrigger(
             "before",
@@ -160,12 +164,11 @@ class PresenceHandler(object):
             self._on_shutdown,
         )
 
-        self.serial_to_user = {}
         self._next_serial = 1
 
         # Keeps track of the number of *ongoing* syncs on this process. While
         # this is non zero a user will never go offline.
-        self.user_to_num_current_syncs = {}
+        self.user_to_num_current_syncs = {}  # type: Dict[str, int]
 
         # Keeps track of the number of *ongoing* syncs on other processes.
         # While any sync is ongoing on another process the user will never
@@ -213,8 +216,7 @@ class PresenceHandler(object):
         self._event_pos = self.store.get_current_events_token()
         self._event_processing = False
 
-    @defer.inlineCallbacks
-    def _on_shutdown(self):
+    async def _on_shutdown(self):
         """Gets called when shutting down. This lets us persist any updates that
         we haven't yet persisted, e.g. updates that only changes some internal
         timers. This allows changes to persist across startup without having to
@@ -235,7 +237,7 @@ class PresenceHandler(object):
 
         if self.unpersisted_users_changes:
 
-            yield self.store.update_presence(
+            await self.store.update_presence(
                 [
                     self.user_to_current_state[user_id]
                     for user_id in self.unpersisted_users_changes
@@ -243,8 +245,7 @@ class PresenceHandler(object):
             )
         logger.info("Finished _on_shutdown")
 
-    @defer.inlineCallbacks
-    def _persist_unpersisted_changes(self):
+    async def _persist_unpersisted_changes(self):
         """We periodically persist the unpersisted changes, as otherwise they
         may stack up and slow down shutdown times.
         """
@@ -253,12 +254,11 @@ class PresenceHandler(object):
 
         if unpersisted:
             logger.info("Persisting %d unpersisted presence updates", len(unpersisted))
-            yield self.store.update_presence(
+            await self.store.update_presence(
                 [self.user_to_current_state[user_id] for user_id in unpersisted]
             )
 
-    @defer.inlineCallbacks
-    def _update_states(self, new_states):
+    async def _update_states(self, new_states):
         """Updates presence of users. Sets the appropriate timeouts. Pokes
         the notifier and federation if and only if the changed presence state
         should be sent to clients/servers.
@@ -267,7 +267,7 @@ class PresenceHandler(object):
 
         with Measure(self.clock, "presence_update_states"):
 
-            # NOTE: We purposefully don't yield between now and when we've
+            # NOTE: We purposefully don't await between now and when we've
             # calculated what we want to do with the new states, to avoid races.
 
             to_notify = {}  # Changes we want to notify everyone about
@@ -311,9 +311,9 @@ class PresenceHandler(object):
 
             if to_notify:
                 notified_presence_counter.inc(len(to_notify))
-                yield self._persist_and_notify(list(to_notify.values()))
+                await self._persist_and_notify(list(to_notify.values()))
 
-            self.unpersisted_users_changes |= set(s.user_id for s in new_states)
+            self.unpersisted_users_changes |= {s.user_id for s in new_states}
             self.unpersisted_users_changes -= set(to_notify.keys())
 
             to_federation_ping = {
@@ -326,7 +326,7 @@ class PresenceHandler(object):
 
                 self._push_to_remotes(to_federation_ping.values())
 
-    def _handle_timeouts(self):
+    async def _handle_timeouts(self):
         """Checks the presence of users that have timed out and updates as
         appropriate.
         """
@@ -368,10 +368,9 @@ class PresenceHandler(object):
             now=now,
         )
 
-        return self._update_states(changes)
+        return await self._update_states(changes)
 
-    @defer.inlineCallbacks
-    def bump_presence_active_time(self, user):
+    async def bump_presence_active_time(self, user):
         """We've seen the user do something that indicates they're interacting
         with the app.
         """
@@ -383,16 +382,17 @@ class PresenceHandler(object):
 
         bump_active_time_counter.inc()
 
-        prev_state = yield self.current_state_for_user(user_id)
+        prev_state = await self.current_state_for_user(user_id)
 
         new_fields = {"last_active_ts": self.clock.time_msec()}
         if prev_state.state == PresenceState.UNAVAILABLE:
             new_fields["state"] = PresenceState.ONLINE
 
-        yield self._update_states([prev_state.copy_and_replace(**new_fields)])
+        await self._update_states([prev_state.copy_and_replace(**new_fields)])
 
-    @defer.inlineCallbacks
-    def user_syncing(self, user_id, affect_presence=True):
+    async def user_syncing(
+        self, user_id: str, affect_presence: bool = True
+    ) -> ContextManager[None]:
         """Returns a context manager that should surround any stream requests
         from the user.
 
@@ -415,11 +415,11 @@ class PresenceHandler(object):
             curr_sync = self.user_to_num_current_syncs.get(user_id, 0)
             self.user_to_num_current_syncs[user_id] = curr_sync + 1
 
-            prev_state = yield self.current_state_for_user(user_id)
+            prev_state = await self.current_state_for_user(user_id)
             if prev_state.state == PresenceState.OFFLINE:
                 # If they're currently offline then bring them online, otherwise
                 # just update the last sync times.
-                yield self._update_states(
+                await self._update_states(
                     [
                         prev_state.copy_and_replace(
                             state=PresenceState.ONLINE,
@@ -429,7 +429,7 @@ class PresenceHandler(object):
                     ]
                 )
             else:
-                yield self._update_states(
+                await self._update_states(
                     [
                         prev_state.copy_and_replace(
                             last_user_sync_ts=self.clock.time_msec()
@@ -437,13 +437,12 @@ class PresenceHandler(object):
                     ]
                 )
 
-        @defer.inlineCallbacks
-        def _end():
+        async def _end():
             try:
                 self.user_to_num_current_syncs[user_id] -= 1
 
-                prev_state = yield self.current_state_for_user(user_id)
-                yield self._update_states(
+                prev_state = await self.current_state_for_user(user_id)
+                await self._update_states(
                     [
                         prev_state.copy_and_replace(
                             last_user_sync_ts=self.clock.time_msec()
@@ -480,8 +479,7 @@ class PresenceHandler(object):
         else:
             return set()
 
-    @defer.inlineCallbacks
-    def update_external_syncs_row(
+    async def update_external_syncs_row(
         self, process_id, user_id, is_syncing, sync_time_msec
     ):
         """Update the syncing users for an external process as a delta.
@@ -494,8 +492,8 @@ class PresenceHandler(object):
             is_syncing (bool): Whether or not the user is now syncing
             sync_time_msec(int): Time in ms when the user was last syncing
         """
-        with (yield self.external_sync_linearizer.queue(process_id)):
-            prev_state = yield self.current_state_for_user(user_id)
+        with (await self.external_sync_linearizer.queue(process_id)):
+            prev_state = await self.current_state_for_user(user_id)
 
             process_presence = self.external_process_to_current_syncs.setdefault(
                 process_id, set()
@@ -525,25 +523,24 @@ class PresenceHandler(object):
                 process_presence.discard(user_id)
 
             if updates:
-                yield self._update_states(updates)
+                await self._update_states(updates)
 
             self.external_process_last_updated_ms[process_id] = self.clock.time_msec()
 
-    @defer.inlineCallbacks
-    def update_external_syncs_clear(self, process_id):
+    async def update_external_syncs_clear(self, process_id):
         """Marks all users that had been marked as syncing by a given process
         as offline.
 
         Used when the process has stopped/disappeared.
         """
-        with (yield self.external_sync_linearizer.queue(process_id)):
+        with (await self.external_sync_linearizer.queue(process_id)):
             process_presence = self.external_process_to_current_syncs.pop(
                 process_id, set()
             )
-            prev_states = yield self.current_state_for_users(process_presence)
+            prev_states = await self.current_state_for_users(process_presence)
             time_now_ms = self.clock.time_msec()
 
-            yield self._update_states(
+            await self._update_states(
                 [
                     prev_state.copy_and_replace(last_user_sync_ts=time_now_ms)
                     for prev_state in itervalues(prev_states)
@@ -551,15 +548,13 @@ class PresenceHandler(object):
             )
             self.external_process_last_updated_ms.pop(process_id, None)
 
-    @defer.inlineCallbacks
-    def current_state_for_user(self, user_id):
+    async def current_state_for_user(self, user_id):
         """Get the current presence state for a user.
         """
-        res = yield self.current_state_for_users([user_id])
+        res = await self.current_state_for_users([user_id])
         return res[user_id]
 
-    @defer.inlineCallbacks
-    def current_state_for_users(self, user_ids):
+    async def current_state_for_users(self, user_ids):
         """Get the current presence state for multiple users.
 
         Returns:
@@ -574,7 +569,7 @@ class PresenceHandler(object):
         if missing:
             # There are things not in our in memory cache. Lets pull them out of
             # the database.
-            res = yield self.store.get_presence_for_users(missing)
+            res = await self.store.get_presence_for_users(missing)
             states.update(res)
 
             missing = [user_id for user_id, state in iteritems(states) if not state]
@@ -587,14 +582,13 @@ class PresenceHandler(object):
 
         return states
 
-    @defer.inlineCallbacks
-    def _persist_and_notify(self, states):
+    async def _persist_and_notify(self, states):
         """Persist states in the database, poke the notifier and send to
         interested remote servers
         """
-        stream_id, max_token = yield self.store.update_presence(states)
+        stream_id, max_token = await self.store.update_presence(states)
 
-        parties = yield get_interested_parties(self.store, states)
+        parties = await get_interested_parties(self.store, states)
         room_ids_to_states, users_to_states = parties
 
         self.notifier.on_new_event(
@@ -606,9 +600,8 @@ class PresenceHandler(object):
 
         self._push_to_remotes(states)
 
-    @defer.inlineCallbacks
-    def notify_for_states(self, state, stream_id):
-        parties = yield get_interested_parties(self.store, [state])
+    async def notify_for_states(self, state, stream_id):
+        parties = await get_interested_parties(self.store, [state])
         room_ids_to_states, users_to_states = parties
 
         self.notifier.on_new_event(
@@ -626,8 +619,7 @@ class PresenceHandler(object):
         """
         self.federation.send_presence(states)
 
-    @defer.inlineCallbacks
-    def incoming_presence(self, origin, content):
+    async def incoming_presence(self, origin, content):
         """Called when we receive a `m.presence` EDU from a remote server.
         """
         now = self.clock.time_msec()
@@ -670,21 +662,19 @@ class PresenceHandler(object):
             new_fields["status_msg"] = push.get("status_msg", None)
             new_fields["currently_active"] = push.get("currently_active", False)
 
-            prev_state = yield self.current_state_for_user(user_id)
+            prev_state = await self.current_state_for_user(user_id)
             updates.append(prev_state.copy_and_replace(**new_fields))
 
         if updates:
             federation_presence_counter.inc(len(updates))
-            yield self._update_states(updates)
+            await self._update_states(updates)
 
-    @defer.inlineCallbacks
-    def get_state(self, target_user, as_event=False):
-        results = yield self.get_states([target_user.to_string()], as_event=as_event)
+    async def get_state(self, target_user, as_event=False):
+        results = await self.get_states([target_user.to_string()], as_event=as_event)
 
         return results[0]
 
-    @defer.inlineCallbacks
-    def get_states(self, target_user_ids, as_event=False):
+    async def get_states(self, target_user_ids, as_event=False):
         """Get the presence state for users.
 
         Args:
@@ -695,10 +685,10 @@ class PresenceHandler(object):
             list
         """
 
-        updates = yield self.current_state_for_users(target_user_ids)
+        updates = await self.current_state_for_users(target_user_ids)
         updates = list(updates.values())
 
-        for user_id in set(target_user_ids) - set(u.user_id for u in updates):
+        for user_id in set(target_user_ids) - {u.user_id for u in updates}:
             updates.append(UserPresenceState.default(user_id))
 
         now = self.clock.time_msec()
@@ -713,8 +703,7 @@ class PresenceHandler(object):
         else:
             return updates
 
-    @defer.inlineCallbacks
-    def set_state(self, target_user, state, ignore_status_msg=False):
+    async def set_state(self, target_user, state, ignore_status_msg=False):
         """Set the presence state of the user.
         """
         status_msg = state.get("status_msg", None)
@@ -730,7 +719,7 @@ class PresenceHandler(object):
 
         user_id = target_user.to_string()
 
-        prev_state = yield self.current_state_for_user(user_id)
+        prev_state = await self.current_state_for_user(user_id)
 
         new_fields = {"state": presence}
 
@@ -741,16 +730,15 @@ class PresenceHandler(object):
         if presence == PresenceState.ONLINE:
             new_fields["last_active_ts"] = self.clock.time_msec()
 
-        yield self._update_states([prev_state.copy_and_replace(**new_fields)])
+        await self._update_states([prev_state.copy_and_replace(**new_fields)])
 
-    @defer.inlineCallbacks
-    def is_visible(self, observed_user, observer_user):
+    async def is_visible(self, observed_user, observer_user):
         """Returns whether a user can see another user's presence.
         """
-        observer_room_ids = yield self.store.get_rooms_for_user(
+        observer_room_ids = await self.store.get_rooms_for_user(
             observer_user.to_string()
         )
-        observed_room_ids = yield self.store.get_rooms_for_user(
+        observed_room_ids = await self.store.get_rooms_for_user(
             observed_user.to_string()
         )
 
@@ -759,8 +747,7 @@ class PresenceHandler(object):
 
         return False
 
-    @defer.inlineCallbacks
-    def get_all_presence_updates(self, last_id, current_id):
+    async def get_all_presence_updates(self, last_id, current_id):
         """
         Gets a list of presence update rows from between the given stream ids.
         Each row has:
@@ -775,7 +762,7 @@ class PresenceHandler(object):
         """
         # TODO(markjh): replicate the unpersisted changes.
         # This could use the in-memory stores for recent changes.
-        rows = yield self.store.get_all_presence_updates(last_id, current_id)
+        rows = await self.store.get_all_presence_updates(last_id, current_id)
         return rows
 
     def notify_new_event(self):
@@ -786,20 +773,18 @@ class PresenceHandler(object):
         if self._event_processing:
             return
 
-        @defer.inlineCallbacks
-        def _process_presence():
+        async def _process_presence():
             assert not self._event_processing
 
             self._event_processing = True
             try:
-                yield self._unsafe_process()
+                await self._unsafe_process()
             finally:
                 self._event_processing = False
 
         run_as_background_process("presence.notify_new_event", _process_presence)
 
-    @defer.inlineCallbacks
-    def _unsafe_process(self):
+    async def _unsafe_process(self):
         # Loop round handling deltas until we're up to date
         while True:
             with Measure(self.clock, "presence_delta"):
@@ -812,10 +797,10 @@ class PresenceHandler(object):
                     self._event_pos,
                     room_max_stream_ordering,
                 )
-                max_pos, deltas = yield self.store.get_current_state_deltas(
+                max_pos, deltas = await self.store.get_current_state_deltas(
                     self._event_pos, room_max_stream_ordering
                 )
-                yield self._handle_state_delta(deltas)
+                await self._handle_state_delta(deltas)
 
                 self._event_pos = max_pos
 
@@ -824,8 +809,7 @@ class PresenceHandler(object):
                     max_pos
                 )
 
-    @defer.inlineCallbacks
-    def _handle_state_delta(self, deltas):
+    async def _handle_state_delta(self, deltas):
         """Process current state deltas to find new joins that need to be
         handled.
         """
@@ -846,13 +830,13 @@ class PresenceHandler(object):
                 # joins.
                 continue
 
-            event = yield self.store.get_event(event_id, allow_none=True)
+            event = await self.store.get_event(event_id, allow_none=True)
             if not event or event.content.get("membership") != Membership.JOIN:
                 # We only care about joins
                 continue
 
             if prev_event_id:
-                prev_event = yield self.store.get_event(prev_event_id, allow_none=True)
+                prev_event = await self.store.get_event(prev_event_id, allow_none=True)
                 if (
                     prev_event
                     and prev_event.content.get("membership") == Membership.JOIN
@@ -860,10 +844,9 @@ class PresenceHandler(object):
                     # Ignore changes to join events.
                     continue
 
-            yield self._on_user_joined_room(room_id, state_key)
+            await self._on_user_joined_room(room_id, state_key)
 
-    @defer.inlineCallbacks
-    def _on_user_joined_room(self, room_id, user_id):
+    async def _on_user_joined_room(self, room_id, user_id):
         """Called when we detect a user joining the room via the current state
         delta stream.
 
@@ -882,11 +865,11 @@ class PresenceHandler(object):
             # TODO: We should be able to filter the hosts down to those that
             # haven't previously seen the user
 
-            state = yield self.current_state_for_user(user_id)
-            hosts = yield self.state.get_current_hosts_in_room(room_id)
+            state = await self.current_state_for_user(user_id)
+            hosts = await self.state.get_current_hosts_in_room(room_id)
 
             # Filter out ourselves.
-            hosts = set(host for host in hosts if host != self.server_name)
+            hosts = {host for host in hosts if host != self.server_name}
 
             self.federation.send_presence_to_destinations(
                 states=[state], destinations=hosts
@@ -903,10 +886,10 @@ class PresenceHandler(object):
             # TODO: Check that this is actually a new server joining the
             # room.
 
-            user_ids = yield self.state.get_current_users_in_room(room_id)
+            user_ids = await self.state.get_current_users_in_room(room_id)
             user_ids = list(filter(self.is_mine_id, user_ids))
 
-            states = yield self.current_state_for_users(user_ids)
+            states = await self.current_state_for_users(user_ids)
 
             # Filter out old presence, i.e. offline presence states where
             # the user hasn't been active for a week. We can change this
@@ -996,9 +979,8 @@ class PresenceEventSource(object):
         self.store = hs.get_datastore()
         self.state = hs.get_state_handler()
 
-    @defer.inlineCallbacks
     @log_function
-    def get_new_events(
+    async def get_new_events(
         self,
         user,
         from_key,
@@ -1045,7 +1027,7 @@ class PresenceEventSource(object):
             presence = self.get_presence_handler()
             stream_change_cache = self.store.presence_stream_cache
 
-            users_interested_in = yield self._get_interested_in(user, explicit_room_id)
+            users_interested_in = await self._get_interested_in(user, explicit_room_id)
 
             user_ids_changed = set()
             changed = None
@@ -1071,7 +1053,7 @@ class PresenceEventSource(object):
                 else:
                     user_ids_changed = users_interested_in
 
-            updates = yield presence.current_state_for_users(user_ids_changed)
+            updates = await presence.current_state_for_users(user_ids_changed)
 
         if include_offline:
             return (list(updates.values()), max_token)
@@ -1084,11 +1066,11 @@ class PresenceEventSource(object):
     def get_current_key(self):
         return self.store.get_current_presence_token()
 
-    def get_pagination_rows(self, user, pagination_config, key):
-        return self.get_new_events(user, from_key=None, include_offline=False)
+    async def get_pagination_rows(self, user, pagination_config, key):
+        return await self.get_new_events(user, from_key=None, include_offline=False)
 
-    @cachedInlineCallbacks(num_args=2, cache_context=True)
-    def _get_interested_in(self, user, explicit_room_id, cache_context):
+    @cached(num_args=2, cache_context=True)
+    async def _get_interested_in(self, user, explicit_room_id, cache_context):
         """Returns the set of users that the given user should see presence
         updates for
         """
@@ -1096,13 +1078,13 @@ class PresenceEventSource(object):
         users_interested_in = set()
         users_interested_in.add(user_id)  # So that we receive our own presence
 
-        users_who_share_room = yield self.store.get_users_who_share_room_with_user(
+        users_who_share_room = await self.store.get_users_who_share_room_with_user(
             user_id, on_invalidate=cache_context.invalidate
         )
         users_interested_in.update(users_who_share_room)
 
         if explicit_room_id:
-            user_ids = yield self.store.get_users_in_room(
+            user_ids = await self.store.get_users_in_room(
                 explicit_room_id, on_invalidate=cache_context.invalidate
             )
             users_interested_in.update(user_ids)
@@ -1277,8 +1259,8 @@ def get_interested_parties(store, states):
         2-tuple: `(room_ids_to_states, users_to_states)`,
         with each item being a dict of `entity_name` -> `[UserPresenceState]`
     """
-    room_ids_to_states = {}
-    users_to_states = {}
+    room_ids_to_states = {}  # type: Dict[str, List[UserPresenceState]]
+    users_to_states = {}  # type: Dict[str, List[UserPresenceState]]
     for state in states:
         room_ids = yield store.get_rooms_for_user(state.user_id)
         for room_id in room_ids:
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index f9579d69ee..50ce0c585b 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -28,7 +28,7 @@ from synapse.api.errors import (
     SynapseError,
 )
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.types import UserID, get_domain_from_id
+from synapse.types import UserID, create_requester, get_domain_from_id
 
 from ._base import BaseHandler
 
@@ -165,6 +165,12 @@ class BaseProfileHandler(BaseHandler):
         if new_displayname == "":
             new_displayname = None
 
+        # If the admin changes the display name of a user, the requesting user cannot send
+        # the join event to update the displayname in the rooms.
+        # This must be done by the target user himself.
+        if by_admin:
+            requester = create_requester(target_user)
+
         yield self.store.set_profile_displayname(target_user.localpart, new_displayname)
 
         if self.hs.config.user_directory_search_all_users:
@@ -217,6 +223,10 @@ class BaseProfileHandler(BaseHandler):
                 400, "Avatar URL is too long (max %i)" % (MAX_AVATAR_URL_LEN,)
             )
 
+        # Same like set_displayname
+        if by_admin:
+            requester = create_requester(target_user)
+
         yield self.store.set_profile_avatar_url(target_user.localpart, new_avatar_url)
 
         if self.hs.config.user_directory_search_all_users:
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index 9283c039e3..8bc100db42 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -94,7 +94,7 @@ class ReceiptsHandler(BaseHandler):
             # no new receipts
             return False
 
-        affected_room_ids = list(set([r.room_id for r in receipts]))
+        affected_room_ids = list({r.room_id for r in receipts})
 
         self.notifier.on_new_event("receipt_key", max_batch_id, rooms=affected_room_ids)
         # Note that the min here shouldn't be relied upon to be accurate.
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index ab07edd2fc..8ee870f0bb 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -64,18 +64,21 @@ class RoomCreationHandler(BaseHandler):
             "history_visibility": "shared",
             "original_invitees_have_ops": False,
             "guest_can_join": True,
+            "power_level_content_override": {"invite": 0},
         },
         RoomCreationPreset.TRUSTED_PRIVATE_CHAT: {
             "join_rules": JoinRules.INVITE,
             "history_visibility": "shared",
             "original_invitees_have_ops": True,
             "guest_can_join": True,
+            "power_level_content_override": {"invite": 0},
         },
         RoomCreationPreset.PUBLIC_CHAT: {
             "join_rules": JoinRules.PUBLIC,
             "history_visibility": "shared",
             "original_invitees_have_ops": False,
             "guest_can_join": False,
+            "power_level_content_override": {},
         },
     }
 
@@ -146,7 +149,9 @@ class RoomCreationHandler(BaseHandler):
         return ret
 
     @defer.inlineCallbacks
-    def _upgrade_room(self, requester, old_room_id, new_version):
+    def _upgrade_room(
+        self, requester: Requester, old_room_id: str, new_version: RoomVersion
+    ):
         user_id = requester.user.to_string()
 
         # start by allocating a new room id
@@ -350,7 +355,7 @@ class RoomCreationHandler(BaseHandler):
             # If so, mark the new room as non-federatable as well
             creation_content["m.federate"] = False
 
-        initial_state = dict()
+        initial_state = {}
 
         # Replicate relevant room events
         types_to_copy = (
@@ -445,19 +450,21 @@ class RoomCreationHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def _move_aliases_to_new_room(
-        self, requester, old_room_id, new_room_id, old_room_state
+        self,
+        requester: Requester,
+        old_room_id: str,
+        new_room_id: str,
+        old_room_state: StateMap[str],
     ):
         directory_handler = self.hs.get_handlers().directory_handler
 
         aliases = yield self.store.get_aliases_for_room(old_room_id)
 
         # check to see if we have a canonical alias.
-        canonical_alias = None
+        canonical_alias_event = None
         canonical_alias_event_id = old_room_state.get((EventTypes.CanonicalAlias, ""))
         if canonical_alias_event_id:
             canonical_alias_event = yield self.store.get_event(canonical_alias_event_id)
-            if canonical_alias_event:
-                canonical_alias = canonical_alias_event.content.get("alias", "")
 
         # first we try to remove the aliases from the old room (we suppress sending
         # the room_aliases event until the end).
@@ -475,9 +482,7 @@ class RoomCreationHandler(BaseHandler):
         for alias_str in aliases:
             alias = RoomAlias.from_string(alias_str)
             try:
-                yield directory_handler.delete_association(
-                    requester, alias, send_event=False
-                )
+                yield directory_handler.delete_association(requester, alias)
                 removed_aliases.append(alias_str)
             except SynapseError as e:
                 logger.warning("Unable to remove alias %s from old room: %s", alias, e)
@@ -487,19 +492,6 @@ class RoomCreationHandler(BaseHandler):
         if not removed_aliases:
             return
 
-        try:
-            # this can fail if, for some reason, our user doesn't have perms to send
-            # m.room.aliases events in the old room (note that we've already checked that
-            # they have perms to send a tombstone event, so that's not terribly likely).
-            #
-            # If that happens, it's regrettable, but we should carry on: it's the same
-            # as when you remove an alias from the directory normally - it just means that
-            # the aliases event gets out of sync with the directory
-            # (cf https://github.com/vector-im/riot-web/issues/2369)
-            yield directory_handler.send_room_alias_update_event(requester, old_room_id)
-        except AuthError as e:
-            logger.warning("Failed to send updated alias event on old room: %s", e)
-
         # we can now add any aliases we successfully removed to the new room.
         for alias in removed_aliases:
             try:
@@ -508,7 +500,6 @@ class RoomCreationHandler(BaseHandler):
                     RoomAlias.from_string(alias),
                     new_room_id,
                     servers=(self.hs.hostname,),
-                    send_event=False,
                     check_membership=False,
                 )
                 logger.info("Moved alias %s to new room", alias)
@@ -517,8 +508,10 @@ class RoomCreationHandler(BaseHandler):
                 # checking module decides it shouldn't, or similar.
                 logger.error("Error adding alias %s to new room: %s", alias, e)
 
+        # If a canonical alias event existed for the old room, fire a canonical
+        # alias event for the new room with a copy of the information.
         try:
-            if canonical_alias and (canonical_alias in removed_aliases):
+            if canonical_alias_event:
                 yield self.event_creation_handler.create_and_send_nonmember_event(
                     requester,
                     {
@@ -526,12 +519,10 @@ class RoomCreationHandler(BaseHandler):
                         "state_key": "",
                         "room_id": new_room_id,
                         "sender": requester.user.to_string(),
-                        "content": {"alias": canonical_alias},
+                        "content": canonical_alias_event.content,
                     },
                     ratelimit=False,
                 )
-
-            yield directory_handler.send_room_alias_update_event(requester, new_room_id)
         except SynapseError as e:
             # again I'm not really expecting this to fail, but if it does, I'd rather
             # we returned the new room to the client at this point.
@@ -661,7 +652,6 @@ class RoomCreationHandler(BaseHandler):
                 room_id=room_id,
                 room_alias=room_alias,
                 servers=[self.hs.hostname],
-                send_event=False,
                 check_membership=False,
             )
 
@@ -758,7 +748,6 @@ class RoomCreationHandler(BaseHandler):
 
         if room_alias:
             result["room_alias"] = room_alias.to_string()
-            yield directory_handler.send_room_alias_update_event(requester, room_id)
 
         return result
 
@@ -829,19 +818,24 @@ class RoomCreationHandler(BaseHandler):
                     # This will be reudundant on pre-MSC2260 rooms, since the
                     # aliases event is special-cased.
                     EventTypes.Aliases: 0,
+                    EventTypes.Tombstone: 100,
+                    EventTypes.ServerACL: 100,
                 },
                 "events_default": 0,
                 "state_default": 50,
                 "ban": 50,
                 "kick": 50,
                 "redact": 50,
-                "invite": 0,
+                "invite": 50,
             }
 
             if config["original_invitees_have_ops"]:
                 for invitee in invite_list:
                     power_level_content["users"][invitee] = 100
 
+            # Power levels overrides are defined per chat preset
+            power_level_content.update(config["power_level_content_override"])
+
             if power_level_content_override:
                 power_level_content.update(power_level_content_override)
 
diff --git a/synapse/handlers/room_list.py b/synapse/handlers/room_list.py
index c615206df1..0b7d3da680 100644
--- a/synapse/handlers/room_list.py
+++ b/synapse/handlers/room_list.py
@@ -216,15 +216,6 @@ class RoomListHandler(BaseHandler):
                         direction_is_forward=False,
                     ).to_token()
 
-        for room in results:
-            # populate search result entries with additional fields, namely
-            # 'aliases'
-            room_id = room["room_id"]
-
-            aliases = yield self.store.get_aliases_for_room(room_id)
-            if aliases:
-                room["aliases"] = aliases
-
         response["chunk"] = results
 
         response["total_room_count_estimate"] = yield self.store.count_public_rooms(
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index 110097eab9..ec1542d416 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -184,7 +184,7 @@ class SearchHandler(BaseHandler):
             membership_list=[Membership.JOIN],
             # membership_list=[Membership.JOIN, Membership.LEAVE, Membership.Ban],
         )
-        room_ids = set(r.room_id for r in rooms)
+        room_ids = {r.room_id for r in rooms}
 
         # If doing a subset of all rooms seearch, check if any of the rooms
         # are from an upgraded room, and search their contents as well
@@ -374,12 +374,12 @@ class SearchHandler(BaseHandler):
                 ).to_string()
 
                 if include_profile:
-                    senders = set(
+                    senders = {
                         ev.sender
                         for ev in itertools.chain(
                             res["events_before"], [event], res["events_after"]
                         )
-                    )
+                    }
 
                     if res["events_after"]:
                         last_event_id = res["events_after"][-1].event_id
@@ -421,7 +421,7 @@ class SearchHandler(BaseHandler):
 
         state_results = {}
         if include_state:
-            rooms = set(e.room_id for e in allowed_events)
+            rooms = {e.room_id for e in allowed_events}
             for room_id in rooms:
                 state = yield self.state_handler.get_current_state(room_id)
                 state_results[room_id] = list(state.values())
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 4324bc702e..669dbc8a48 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -682,11 +682,9 @@ class SyncHandler(object):
 
         # FIXME: order by stream ordering rather than as returned by SQL
         if joined_user_ids or invited_user_ids:
-            summary["m.heroes"] = sorted(
-                [user_id for user_id in (joined_user_ids + invited_user_ids)]
-            )[0:5]
+            summary["m.heroes"] = sorted(joined_user_ids + invited_user_ids)[0:5]
         else:
-            summary["m.heroes"] = sorted([user_id for user_id in gone_user_ids])[0:5]
+            summary["m.heroes"] = sorted(gone_user_ids)[0:5]
 
         if not sync_config.filter_collection.lazy_load_members():
             return summary
@@ -697,9 +695,9 @@ class SyncHandler(object):
 
         # track which members the client should already know about via LL:
         # Ones which are already in state...
-        existing_members = set(
+        existing_members = {
             user_id for (typ, user_id) in state.keys() if typ == EventTypes.Member
-        )
+        }
 
         # ...or ones which are in the timeline...
         for ev in batch.events:
@@ -773,10 +771,10 @@ class SyncHandler(object):
                 # We only request state for the members needed to display the
                 # timeline:
 
-                members_to_fetch = set(
+                members_to_fetch = {
                     event.sender  # FIXME: we also care about invite targets etc.
                     for event in batch.events
-                )
+                }
 
                 if full_state:
                     # always make sure we LL ourselves so we know we're in the room
@@ -1993,10 +1991,10 @@ def _calculate_state(
         )
     }
 
-    c_ids = set(e for e in itervalues(current))
-    ts_ids = set(e for e in itervalues(timeline_start))
-    p_ids = set(e for e in itervalues(previous))
-    tc_ids = set(e for e in itervalues(timeline_contains))
+    c_ids = set(itervalues(current))
+    ts_ids = set(itervalues(timeline_start))
+    p_ids = set(itervalues(previous))
+    tc_ids = set(itervalues(timeline_contains))
 
     # If we are lazyloading room members, we explicitly add the membership events
     # for the senders in the timeline into the state block returned by /sync,
diff --git a/synapse/handlers/typing.py b/synapse/handlers/typing.py
index d5ca9cb07b..391bceb0c4 100644
--- a/synapse/handlers/typing.py
+++ b/synapse/handlers/typing.py
@@ -125,7 +125,7 @@ class TypingHandler(object):
         if target_user_id != auth_user_id:
             raise AuthError(400, "Cannot set another user's typing state")
 
-        yield self.auth.check_joined_room(room_id, target_user_id)
+        yield self.auth.check_user_in_room(room_id, target_user_id)
 
         logger.debug("%s has started typing in %s", target_user_id, room_id)
 
@@ -155,7 +155,7 @@ class TypingHandler(object):
         if target_user_id != auth_user_id:
             raise AuthError(400, "Cannot set another user's typing state")
 
-        yield self.auth.check_joined_room(room_id, target_user_id)
+        yield self.auth.check_user_in_room(room_id, target_user_id)
 
         logger.debug("%s has stopped typing in %s", target_user_id, room_id)
 
@@ -198,7 +198,7 @@ class TypingHandler(object):
                 now=now, obj=member, then=now + FEDERATION_PING_INTERVAL
             )
 
-            for domain in set(get_domain_from_id(u) for u in users):
+            for domain in {get_domain_from_id(u) for u in users}:
                 if domain != self.server_name:
                     logger.debug("sending typing update to %s", domain)
                     self.federation.build_and_send_edu(
@@ -231,7 +231,7 @@ class TypingHandler(object):
             return
 
         users = yield self.state.get_current_users_in_room(room_id)
-        domains = set(get_domain_from_id(u) for u in users)
+        domains = {get_domain_from_id(u) for u in users}
 
         if self.server_name in domains:
             logger.info("Got typing update from %s: %r", user_id, content)
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 04bc2385a2..042a605198 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -353,10 +353,12 @@ class JsonResource(HttpServer, resource.Resource):
         if request.method == b"OPTIONS":
             return _options_handler, "options_request_handler", {}
 
+        request_path = request.path.decode("ascii")
+
         # Loop through all the registered callbacks to check if the method
         # and path regex match
         for path_entry in self.path_regexs.get(request.method, []):
-            m = path_entry.pattern.match(request.path.decode("ascii"))
+            m = path_entry.pattern.match(request_path)
             if m:
                 # We found a match!
                 return path_entry.callback, path_entry.servlet_classname, m.groupdict()
diff --git a/synapse/logging/utils.py b/synapse/logging/utils.py
index 6073fc2725..0c2527bd86 100644
--- a/synapse/logging/utils.py
+++ b/synapse/logging/utils.py
@@ -148,7 +148,7 @@ def trace_function(f):
             pathname=pathname,
             lineno=lineno,
             msg=msg,
-            args=tuple(),
+            args=(),
             exc_info=None,
         )
 
diff --git a/synapse/metrics/__init__.py b/synapse/metrics/__init__.py
index 0b45e1f52a..0dba997a23 100644
--- a/synapse/metrics/__init__.py
+++ b/synapse/metrics/__init__.py
@@ -240,7 +240,7 @@ class BucketCollector(object):
         res.append(["+Inf", sum(data.values())])
 
         metric = HistogramMetricFamily(
-            self.name, "", buckets=res, sum_value=sum([x * y for x, y in data.items()])
+            self.name, "", buckets=res, sum_value=sum(x * y for x, y in data.items())
         )
         yield metric
 
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py
index c53d2a0d40..b65bcd8806 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -80,13 +80,13 @@ _background_process_db_sched_duration = Counter(
 # map from description to a counter, so that we can name our logcontexts
 # incrementally. (It actually duplicates _background_process_start_count, but
 # it's much simpler to do so than to try to combine them.)
-_background_process_counts = dict()  # type: dict[str, int]
+_background_process_counts = {}  # type: dict[str, int]
 
 # map from description to the currently running background processes.
 #
 # it's kept as a dict of sets rather than a big set so that we can keep track
 # of process descriptions that no longer have any active processes.
-_background_processes = dict()  # type: dict[str, set[_BackgroundProcess]]
+_background_processes = {}  # type: dict[str, set[_BackgroundProcess]]
 
 # A lock that covers the above dicts
 _bg_metrics_lock = threading.Lock()
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 823ebdaa60..e75d964ac8 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -402,11 +402,11 @@ class RulesForRoom(object):
         if logger.isEnabledFor(logging.DEBUG):
             logger.debug("Found members %r: %r", self.room_id, members.values())
 
-        interested_in_user_ids = set(
+        interested_in_user_ids = {
             user_id
             for user_id, membership in itervalues(members)
             if membership == Membership.JOIN
-        )
+        }
 
         logger.debug("Joined: %r", interested_in_user_ids)
 
@@ -414,9 +414,9 @@ class RulesForRoom(object):
             interested_in_user_ids, on_invalidate=self.invalidate_all_cb
         )
 
-        user_ids = set(
+        user_ids = {
             uid for uid, have_pusher in iteritems(if_users_with_pushers) if have_pusher
-        )
+        }
 
         logger.debug("With pushers: %r", user_ids)
 
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index 8c818a86bf..ba4551d619 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -204,7 +204,7 @@ class EmailPusher(object):
                 yield self.send_notification(unprocessed, reason)
 
                 yield self.save_last_stream_ordering_and_success(
-                    max([ea["stream_ordering"] for ea in unprocessed])
+                    max(ea["stream_ordering"] for ea in unprocessed)
                 )
 
                 # we update the throttle on all the possible unprocessed push actions
diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py
index b13b646bfd..4ccaf178ce 100644
--- a/synapse/push/mailer.py
+++ b/synapse/push/mailer.py
@@ -526,12 +526,10 @@ class Mailer(object):
                     # If the room doesn't have a name, say who the messages
                     # are from explicitly to avoid, "messages in the Bob room"
                     sender_ids = list(
-                        set(
-                            [
-                                notif_events[n["event_id"]].sender
-                                for n in notifs_by_room[room_id]
-                            ]
-                        )
+                        {
+                            notif_events[n["event_id"]].sender
+                            for n in notifs_by_room[room_id]
+                        }
                     )
 
                     member_events = yield self.store.get_events(
@@ -558,12 +556,10 @@ class Mailer(object):
                 # If the reason room doesn't have a name, say who the messages
                 # are from explicitly to avoid, "messages in the Bob room"
                 sender_ids = list(
-                    set(
-                        [
-                            notif_events[n["event_id"]].sender
-                            for n in notifs_by_room[reason["room_id"]]
-                        ]
-                    )
+                    {
+                        notif_events[n["event_id"]].sender
+                        for n in notifs_by_room[reason["room_id"]]
+                    }
                 )
 
                 member_events = yield self.store.get_events(
diff --git a/synapse/push/presentable_names.py b/synapse/push/presentable_names.py
index 16a7e8e31d..0644a13cfc 100644
--- a/synapse/push/presentable_names.py
+++ b/synapse/push/presentable_names.py
@@ -18,6 +18,8 @@ import re
 
 from twisted.internet import defer
 
+from synapse.api.constants import EventTypes
+
 logger = logging.getLogger(__name__)
 
 # intentionally looser than what aliases we allow to be registered since
@@ -50,17 +52,17 @@ def calculate_room_name(
         (string or None) A human readable name for the room.
     """
     # does it have a name?
-    if ("m.room.name", "") in room_state_ids:
+    if (EventTypes.Name, "") in room_state_ids:
         m_room_name = yield store.get_event(
-            room_state_ids[("m.room.name", "")], allow_none=True
+            room_state_ids[(EventTypes.Name, "")], allow_none=True
         )
         if m_room_name and m_room_name.content and m_room_name.content["name"]:
             return m_room_name.content["name"]
 
     # does it have a canonical alias?
-    if ("m.room.canonical_alias", "") in room_state_ids:
+    if (EventTypes.CanonicalAlias, "") in room_state_ids:
         canon_alias = yield store.get_event(
-            room_state_ids[("m.room.canonical_alias", "")], allow_none=True
+            room_state_ids[(EventTypes.CanonicalAlias, "")], allow_none=True
         )
         if (
             canon_alias
@@ -74,32 +76,22 @@ def calculate_room_name(
     # for an event type, so rearrange the data structure
     room_state_bytype_ids = _state_as_two_level_dict(room_state_ids)
 
-    # right then, any aliases at all?
-    if "m.room.aliases" in room_state_bytype_ids:
-        m_room_aliases = room_state_bytype_ids["m.room.aliases"]
-        for alias_id in m_room_aliases.values():
-            alias_event = yield store.get_event(alias_id, allow_none=True)
-            if alias_event and alias_event.content.get("aliases"):
-                the_aliases = alias_event.content["aliases"]
-                if len(the_aliases) > 0 and _looks_like_an_alias(the_aliases[0]):
-                    return the_aliases[0]
-
     if not fallback_to_members:
         return None
 
     my_member_event = None
-    if ("m.room.member", user_id) in room_state_ids:
+    if (EventTypes.Member, user_id) in room_state_ids:
         my_member_event = yield store.get_event(
-            room_state_ids[("m.room.member", user_id)], allow_none=True
+            room_state_ids[(EventTypes.Member, user_id)], allow_none=True
         )
 
     if (
         my_member_event is not None
         and my_member_event.content["membership"] == "invite"
     ):
-        if ("m.room.member", my_member_event.sender) in room_state_ids:
+        if (EventTypes.Member, my_member_event.sender) in room_state_ids:
             inviter_member_event = yield store.get_event(
-                room_state_ids[("m.room.member", my_member_event.sender)],
+                room_state_ids[(EventTypes.Member, my_member_event.sender)],
                 allow_none=True,
             )
             if inviter_member_event:
@@ -114,9 +106,9 @@ def calculate_room_name(
 
     # we're going to have to generate a name based on who's in the room,
     # so find out who is in the room that isn't the user.
-    if "m.room.member" in room_state_bytype_ids:
+    if EventTypes.Member in room_state_bytype_ids:
         member_events = yield store.get_events(
-            list(room_state_bytype_ids["m.room.member"].values())
+            list(room_state_bytype_ids[EventTypes.Member].values())
         )
         all_members = [
             ev
@@ -138,9 +130,9 @@ def calculate_room_name(
             # self-chat, peeked room with 1 participant,
             # or inbound invite, or outbound 3PID invite.
             if all_members[0].sender == user_id:
-                if "m.room.third_party_invite" in room_state_bytype_ids:
+                if EventTypes.ThirdPartyInvite in room_state_bytype_ids:
                     third_party_invites = room_state_bytype_ids[
-                        "m.room.third_party_invite"
+                        EventTypes.ThirdPartyInvite
                     ].values()
 
                     if len(third_party_invites) > 0:
diff --git a/synapse/push/pusherpool.py b/synapse/push/pusherpool.py
index b9dca5bc63..01789a9fb4 100644
--- a/synapse/push/pusherpool.py
+++ b/synapse/push/pusherpool.py
@@ -191,7 +191,7 @@ class PusherPool:
                 min_stream_id - 1, max_stream_id
             )
             # This returns a tuple, user_id is at index 3
-            users_affected = set([r[3] for r in updated_receipts])
+            users_affected = {r[3] for r in updated_receipts}
 
             for u in users_affected:
                 if u in self.pushers:
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index 444eb7b7f4..1be1ccbdf3 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -44,7 +44,7 @@ class ReplicationEndpoint(object):
     """Helper base class for defining new replication HTTP endpoints.
 
     This creates an endpoint under `/_synapse/replication/:NAME/:PATH_ARGS..`
-    (with an `/:txn_id` prefix for cached requests.), where NAME is a name,
+    (with a `/:txn_id` suffix for cached requests), where NAME is a name,
     PATH_ARGS are a tuple of parameters to be encoded in the URL.
 
     For example, if `NAME` is "send_event" and `PATH_ARGS` is `("event_id",)`,
diff --git a/synapse/replication/http/federation.py b/synapse/replication/http/federation.py
index 49a3251372..8794720101 100644
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@@ -17,6 +17,7 @@ import logging
 
 from twisted.internet import defer
 
+from synapse.api.room_versions import KNOWN_ROOM_VERSIONS
 from synapse.events import event_type_from_format_version
 from synapse.events.snapshot import EventContext
 from synapse.http.servlet import parse_json_object_from_request
@@ -211,7 +212,7 @@ class ReplicationCleanRoomRestServlet(ReplicationEndpoint):
 
     Request format:
 
-        POST /_synapse/replication/fed_query/:fed_cleanup_room/:txn_id
+        POST /_synapse/replication/fed_cleanup_room/:room_id/:txn_id
 
         {}
     """
@@ -238,8 +239,41 @@ class ReplicationCleanRoomRestServlet(ReplicationEndpoint):
         return 200, {}
 
 
+class ReplicationStoreRoomOnInviteRestServlet(ReplicationEndpoint):
+    """Called to clean up any data in DB for a given room, ready for the
+    server to join the room.
+
+    Request format:
+
+        POST /_synapse/replication/store_room_on_invite/:room_id/:txn_id
+
+        {
+            "room_version": "1",
+        }
+    """
+
+    NAME = "store_room_on_invite"
+    PATH_ARGS = ("room_id",)
+
+    def __init__(self, hs):
+        super().__init__(hs)
+
+        self.store = hs.get_datastore()
+
+    @staticmethod
+    def _serialize_payload(room_id, room_version):
+        return {"room_version": room_version.identifier}
+
+    async def _handle_request(self, request, room_id):
+        content = parse_json_object_from_request(request)
+        room_version = KNOWN_ROOM_VERSIONS[content["room_version"]]
+        await self.store.maybe_store_room_on_invite(room_id, room_version)
+        return 200, {}
+
+
 def register_servlets(hs, http_server):
     ReplicationFederationSendEventsRestServlet(hs).register(http_server)
     ReplicationFederationSendEduRestServlet(hs).register(http_server)
     ReplicationGetQueryRestServlet(hs).register(http_server)
     ReplicationCleanRoomRestServlet(hs).register(http_server)
+    ReplicationStoreRoomOnInviteRestServlet(hs).register(http_server)
diff --git a/synapse/replication/slave/storage/events.py b/synapse/replication/slave/storage/events.py
index 3aa6cb8b96..e73342c657 100644
--- a/synapse/replication/slave/storage/events.py
+++ b/synapse/replication/slave/storage/events.py
@@ -32,6 +32,7 @@ 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.util.caches.stream_change_cache import StreamChangeCache
 
 from ._base import BaseSlavedStore
 from ._slaved_id_tracker import SlavedIdTracker
@@ -68,6 +69,21 @@ class SlavedEventStore(
 
         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(
+            db_conn,
+            "current_state_delta_stream",
+            entity_column="room_id",
+            stream_column="stream_id",
+            max_value=events_max,  # As we share the stream id with events token
+            limit=1000,
+        )
+        self._curr_state_delta_stream_cache = StreamChangeCache(
+            "_curr_state_delta_stream_cache",
+            min_curr_state_delta_id,
+            prefilled_cache=curr_state_delta_prefill,
+        )
+
     # Cached functions can't be accessed through a class instance so we need
     # to reach inside the __dict__ to extract them.
 
@@ -120,6 +136,10 @@ class SlavedEventStore(
                 backfilled=False,
             )
         elif row.type == EventsStreamCurrentStateRow.TypeId:
+            self._curr_state_delta_stream_cache.entity_has_changed(
+                row.data.room_id, token
+            )
+
             if data.type == EventTypes.Member:
                 self.get_rooms_for_user_with_stream_ordering.invalidate(
                     (data.state_key,)
diff --git a/synapse/replication/tcp/resource.py b/synapse/replication/tcp/resource.py
index ce60ae2e07..ce9d1fae12 100644
--- a/synapse/replication/tcp/resource.py
+++ b/synapse/replication/tcp/resource.py
@@ -323,7 +323,11 @@ class ReplicationStreamer(object):
 
         # We need to tell the presence handler that the connection has been
         # lost so that it can handle any ongoing syncs on that connection.
-        self.presence_handler.update_external_syncs_clear(connection.conn_id)
+        run_as_background_process(
+            "update_external_syncs_clear",
+            self.presence_handler.update_external_syncs_clear,
+            connection.conn_id,
+        )
 
 
 def _batch_updates(updates):
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index a8d568b14a..208e8a667b 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -24,7 +24,7 @@ import attr
 logger = logging.getLogger(__name__)
 
 
-MAX_EVENTS_BEHIND = 10000
+MAX_EVENTS_BEHIND = 500000
 
 BackfillStreamRow = namedtuple(
     "BackfillStreamRow",
diff --git a/synapse/rest/admin/_base.py b/synapse/rest/admin/_base.py
index 459482eb6d..a96f75ce26 100644
--- a/synapse/rest/admin/_base.py
+++ b/synapse/rest/admin/_base.py
@@ -29,7 +29,7 @@ def historical_admin_path_patterns(path_regex):
     Note that this should only be used for existing endpoints: new ones should just
     register for the /_synapse/admin path.
     """
-    return list(
+    return [
         re.compile(prefix + path_regex)
         for prefix in (
             "^/_synapse/admin/v1",
@@ -37,7 +37,7 @@ def historical_admin_path_patterns(path_regex):
             "^/_matrix/client/unstable/admin",
             "^/_matrix/client/r0/admin",
         )
-    )
+    ]
 
 
 def admin_patterns(path_regex: str):
diff --git a/synapse/rest/admin/users.py b/synapse/rest/admin/users.py
index 2107b5dc56..c5b461a236 100644
--- a/synapse/rest/admin/users.py
+++ b/synapse/rest/admin/users.py
@@ -228,13 +228,16 @@ class UserRestServletV2(RestServlet):
                     )
 
             if "deactivated" in body:
-                deactivate = bool(body["deactivated"])
+                deactivate = body["deactivated"]
+                if not isinstance(deactivate, bool):
+                    raise SynapseError(
+                        400, "'deactivated' parameter is not of type boolean"
+                    )
+
                 if deactivate and not user["deactivated"]:
-                    result = await self.deactivate_account_handler.deactivate_account(
+                    await self.deactivate_account_handler.deactivate_account(
                         target_user.to_string(), False
                     )
-                    if not result:
-                        raise SynapseError(500, "Could not deactivate user")
 
             user = await self.admin_handler.get_user(target_user)
             return 200, user
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 1294e080dc..2c99536678 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -599,6 +599,7 @@ class SSOAuthHandler(object):
         redirect_url = self._add_login_token_to_redirect_url(
             client_redirect_url, login_token
         )
+        # Load page
         request.redirect(redirect_url)
         finish_request(request)
 
diff --git a/synapse/rest/client/v1/push_rule.py b/synapse/rest/client/v1/push_rule.py
index 4f74600239..9fd4908136 100644
--- a/synapse/rest/client/v1/push_rule.py
+++ b/synapse/rest/client/v1/push_rule.py
@@ -49,7 +49,7 @@ class PushRuleRestServlet(RestServlet):
         if self._is_worker:
             raise Exception("Cannot handle PUT /push_rules on worker")
 
-        spec = _rule_spec_from_path([x for x in path.split("/")])
+        spec = _rule_spec_from_path(path.split("/"))
         try:
             priority_class = _priority_class_from_spec(spec)
         except InvalidRuleException as e:
@@ -110,7 +110,7 @@ class PushRuleRestServlet(RestServlet):
         if self._is_worker:
             raise Exception("Cannot handle DELETE /push_rules on worker")
 
-        spec = _rule_spec_from_path([x for x in path.split("/")])
+        spec = _rule_spec_from_path(path.split("/"))
 
         requester = await self.auth.get_user_by_req(request)
         user_id = requester.user.to_string()
@@ -138,7 +138,7 @@ class PushRuleRestServlet(RestServlet):
 
         rules = format_push_rules_for_user(requester.user, rules)
 
-        path = [x for x in path.split("/")][1:]
+        path = path.split("/")[1:]
 
         if path == []:
             # we're a reference impl: pedantry is our job.
diff --git a/synapse/rest/client/v1/pusher.py b/synapse/rest/client/v1/pusher.py
index 6f6b7aed6e..550a2f1b44 100644
--- a/synapse/rest/client/v1/pusher.py
+++ b/synapse/rest/client/v1/pusher.py
@@ -54,9 +54,9 @@ class PushersRestServlet(RestServlet):
 
         pushers = await self.hs.get_datastore().get_pushers_by_user_id(user.to_string())
 
-        filtered_pushers = list(
+        filtered_pushers = [
             {k: v for k, v in p.items() if k in ALLOWED_KEYS} for p in pushers
-        )
+        ]
 
         return 200, {"pushers": filtered_pushers}
 
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 6f31584c51..64f51406fb 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -16,6 +16,7 @@
 
 """ This module contains REST servlets to do with rooms: /rooms/<paths> """
 import logging
+import re
 from typing import List, Optional
 
 from six.moves.urllib import parse as urlparse
@@ -45,6 +46,10 @@ from synapse.storage.state import StateFilter
 from synapse.streams.config import PaginationConfig
 from synapse.types import RoomAlias, RoomID, StreamToken, ThirdPartyInstanceID, UserID
 
+MYPY = False
+if MYPY:
+    import synapse.server
+
 logger = logging.getLogger(__name__)
 
 
@@ -843,6 +848,29 @@ class RoomTypingRestServlet(RestServlet):
         return 200, {}
 
 
+class RoomAliasListServlet(RestServlet):
+    PATTERNS = [
+        re.compile(
+            r"^/_matrix/client/unstable/org\.matrix\.msc2432"
+            r"/rooms/(?P<room_id>[^/]*)/aliases"
+        ),
+    ]
+
+    def __init__(self, hs: "synapse.server.HomeServer"):
+        super().__init__()
+        self.auth = hs.get_auth()
+        self.directory_handler = hs.get_handlers().directory_handler
+
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
+
+        alias_list = await self.directory_handler.get_aliases_for_room(
+            requester, room_id
+        )
+
+        return 200, {"aliases": alias_list}
+
+
 class SearchRestServlet(RestServlet):
     PATTERNS = client_patterns("/search$", v1=True)
 
@@ -931,6 +959,7 @@ def register_servlets(hs, http_server):
     JoinedRoomsRestServlet(hs).register(http_server)
     RoomEventServlet(hs).register(http_server)
     RoomEventContextServlet(hs).register(http_server)
+    RoomAliasListServlet(hs).register(http_server)
 
 
 def register_deprecated_servlets(hs, http_server):
diff --git a/synapse/rest/client/v2_alpha/relations.py b/synapse/rest/client/v2_alpha/relations.py
index 9be9a34b91..63f07b63da 100644
--- a/synapse/rest/client/v2_alpha/relations.py
+++ b/synapse/rest/client/v2_alpha/relations.py
@@ -142,8 +142,8 @@ class RelationPaginationServlet(RestServlet):
     ):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        await self.auth.check_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+        await self.auth.check_user_in_room_or_world_readable(
+            room_id, requester.user.to_string(), allow_departed_users=True
         )
 
         # This gets the original event and checks that a) the event exists and
@@ -235,8 +235,8 @@ class RelationAggregationPaginationServlet(RestServlet):
     ):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        await self.auth.check_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+        await self.auth.check_user_in_room_or_world_readable(
+            room_id, requester.user.to_string(), allow_departed_users=True,
         )
 
         # This checks that a) the event exists and b) the user is allowed to
@@ -313,8 +313,8 @@ class RelationAggregationGroupPaginationServlet(RestServlet):
     async def on_GET(self, request, room_id, parent_id, relation_type, event_type, key):
         requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        await self.auth.check_in_room_or_world_readable(
-            room_id, requester.user.to_string()
+        await self.auth.check_user_in_room_or_world_readable(
+            room_id, requester.user.to_string(), allow_departed_users=True,
         )
 
         # This checks that a) the event exists and b) the user is allowed to
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index d8292ce29f..8fa68dd37f 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -72,7 +72,7 @@ class SyncRestServlet(RestServlet):
     """
 
     PATTERNS = client_patterns("/sync$")
-    ALLOWED_PRESENCE = set(["online", "offline", "unavailable"])
+    ALLOWED_PRESENCE = {"online", "offline", "unavailable"}
 
     def __init__(self, hs):
         super(SyncRestServlet, self).__init__()
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 3eeb3607f4..d90a6a890b 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -72,6 +72,8 @@ class VersionsRestServlet(RestServlet):
                     "org.matrix.label_based_filtering": True,
                     # Implements support for cross signing as described in MSC1756
                     "org.matrix.e2e_cross_signing": True,
+                    # Implements additional endpoints as described in MSC2432
+                    "org.matrix.msc2432": True,
                 },
             },
         )
diff --git a/synapse/rest/key/v2/remote_key_resource.py b/synapse/rest/key/v2/remote_key_resource.py
index 9d6813a047..4b6d030a57 100644
--- a/synapse/rest/key/v2/remote_key_resource.py
+++ b/synapse/rest/key/v2/remote_key_resource.py
@@ -149,7 +149,7 @@ class RemoteKey(DirectServeResource):
 
         time_now_ms = self.clock.time_msec()
 
-        cache_misses = dict()  # type: Dict[str, Set[str]]
+        cache_misses = {}  # type: Dict[str, Set[str]]
         for (server_name, key_id, from_server), results in cached.items():
             results = [(result["ts_added_ms"], result) for result in results]
 
diff --git a/synapse/rest/media/v1/_base.py b/synapse/rest/media/v1/_base.py
index 65bbf00073..ba28dd089d 100644
--- a/synapse/rest/media/v1/_base.py
+++ b/synapse/rest/media/v1/_base.py
@@ -135,27 +135,25 @@ def add_file_headers(request, media_type, file_size, upload_name):
 
 # separators as defined in RFC2616. SP and HT are handled separately.
 # see _can_encode_filename_as_token.
-_FILENAME_SEPARATOR_CHARS = set(
-    (
-        "(",
-        ")",
-        "<",
-        ">",
-        "@",
-        ",",
-        ";",
-        ":",
-        "\\",
-        '"',
-        "/",
-        "[",
-        "]",
-        "?",
-        "=",
-        "{",
-        "}",
-    )
-)
+_FILENAME_SEPARATOR_CHARS = {
+    "(",
+    ")",
+    "<",
+    ">",
+    "@",
+    ",",
+    ";",
+    ":",
+    "\\",
+    '"',
+    "/",
+    "[",
+    "]",
+    "?",
+    "=",
+    "{",
+    "}",
+}
 
 
 def _can_encode_filename_as_token(x):
diff --git a/synapse/server.pyi b/synapse/server.pyi
index 40eabfe5d9..3844f0e12f 100644
--- a/synapse/server.pyi
+++ b/synapse/server.pyi
@@ -3,6 +3,7 @@ import twisted.internet
 import synapse.api.auth
 import synapse.config.homeserver
 import synapse.crypto.keyring
+import synapse.federation.federation_server
 import synapse.federation.sender
 import synapse.federation.transport.client
 import synapse.handlers
@@ -107,5 +108,9 @@ class HomeServer(object):
         self,
     ) -> synapse.replication.tcp.client.ReplicationClientHandler:
         pass
+    def get_federation_registry(
+        self,
+    ) -> synapse.federation.federation_server.FederationHandlerRegistry:
+        pass
     def is_mine_id(self, domain_id: str) -> bool:
         pass
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index e038a75a3c..617e5ec196 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -16,7 +16,7 @@
 
 import logging
 from collections import namedtuple
-from typing import Dict, Iterable, List, Optional
+from typing import Dict, Iterable, List, Optional, Set
 
 from six import iteritems, itervalues
 
@@ -660,7 +660,7 @@ class StateResolutionStore(object):
             allow_rejected=allow_rejected,
         )
 
-    def get_auth_chain(self, event_ids):
+    def get_auth_chain(self, event_ids: List[str], ignore_events: Set[str]):
         """Gets the full auth chain for a set of events (including rejected
         events).
 
@@ -672,11 +672,16 @@ class StateResolutionStore(object):
                presence of rejected events
 
         Args:
-            event_ids (list): The event IDs of the events to fetch the auth
-                chain for. Must be state events.
+            event_ids: The event IDs of the events to fetch the auth chain for.
+                Must be state events.
+            ignore_events: Set of events to exclude from the returned auth
+                chain.
+
 
         Returns:
             Deferred[list[str]]: List of event IDs of the auth chain.
         """
 
-        return self.store.get_auth_chain_ids(event_ids, include_given=True)
+        return self.store.get_auth_chain_ids(
+            event_ids, include_given=True, ignore_events=ignore_events,
+        )
diff --git a/synapse/state/v1.py b/synapse/state/v1.py
index 24b7c0faef..9bf98d06f2 100644
--- a/synapse/state/v1.py
+++ b/synapse/state/v1.py
@@ -69,9 +69,9 @@ def resolve_events_with_store(
 
     unconflicted_state, conflicted_state = _seperate(state_sets)
 
-    needed_events = set(
+    needed_events = {
         event_id for event_ids in itervalues(conflicted_state) for event_id in event_ids
-    )
+    }
     needed_event_count = len(needed_events)
     if event_map is not None:
         needed_events -= set(iterkeys(event_map))
@@ -261,11 +261,11 @@ def _resolve_state_events(conflicted_state, auth_events):
 
 
 def _resolve_auth_events(events, auth_events):
-    reverse = [i for i in reversed(_ordered_events(events))]
+    reverse = list(reversed(_ordered_events(events)))
 
-    auth_keys = set(
+    auth_keys = {
         key for event in events for key in event_auth.auth_types_for_event(event)
-    )
+    }
 
     new_auth_events = {}
     for key in auth_keys:
diff --git a/synapse/state/v2.py b/synapse/state/v2.py
index 531018c6a5..0ffe6d8c14 100644
--- a/synapse/state/v2.py
+++ b/synapse/state/v2.py
@@ -105,7 +105,7 @@ def resolve_events_with_store(
                 % (room_id, event.event_id, event.room_id,)
             )
 
-    full_conflicted_set = set(eid for eid in full_conflicted_set if eid in event_map)
+    full_conflicted_set = {eid for eid in full_conflicted_set if eid in event_map}
 
     logger.debug("%d full_conflicted_set entries", len(full_conflicted_set))
 
@@ -233,7 +233,7 @@ def _get_auth_chain_difference(state_sets, event_map, state_res_store):
 
     auth_sets = []
     for state_set in state_sets:
-        auth_ids = set(
+        auth_ids = {
             eid
             for key, eid in iteritems(state_set)
             if (
@@ -246,9 +246,9 @@ def _get_auth_chain_difference(state_sets, event_map, state_res_store):
                 )
             )
             and eid not in common
-        )
+        }
 
-        auth_chain = yield state_res_store.get_auth_chain(auth_ids)
+        auth_chain = yield state_res_store.get_auth_chain(auth_ids, common)
         auth_ids.update(auth_chain)
 
         auth_sets.append(auth_ids)
@@ -275,7 +275,7 @@ def _seperate(state_sets):
     conflicted_state = {}
 
     for key in set(itertools.chain.from_iterable(state_sets)):
-        event_ids = set(state_set.get(key) for state_set in state_sets)
+        event_ids = {state_set.get(key) for state_set in state_sets}
         if len(event_ids) == 1:
             unconflicted_state[key] = event_ids.pop()
         else:
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index da3b99f93d..13de5f1f62 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -56,7 +56,7 @@ class SQLBaseStore(metaclass=ABCMeta):
             members_changed (iterable[str]): The user_ids of members that have
                 changed
         """
-        for host in set(get_domain_from_id(u) for u in members_changed):
+        for host in {get_domain_from_id(u) for u in members_changed}:
             self._attempt_to_invalidate_cache("is_host_joined", (room_id, host))
             self._attempt_to_invalidate_cache("was_host_joined", (room_id, host))
 
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
index bd547f35cf..eb1a7e5002 100644
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@@ -189,7 +189,7 @@ class BackgroundUpdater(object):
                 keyvalues=None,
                 retcols=("update_name", "depends_on"),
             )
-            in_flight = set(update["update_name"] for update in updates)
+            in_flight = {update["update_name"] for update in updates}
             for update in updates:
                 if update["depends_on"] not in in_flight:
                     self._background_update_queue.append(update["update_name"])
diff --git a/synapse/storage/data_stores/main/__init__.py b/synapse/storage/data_stores/main/__init__.py
index 2700cca822..acca079f23 100644
--- a/synapse/storage/data_stores/main/__init__.py
+++ b/synapse/storage/data_stores/main/__init__.py
@@ -20,6 +20,7 @@ import logging
 import time
 
 from synapse.api.constants import PresenceState
+from synapse.config.homeserver import HomeServerConfig
 from synapse.storage.database import Database
 from synapse.storage.engines import PostgresEngine
 from synapse.storage.util.id_generators import (
@@ -117,16 +118,6 @@ class DataStore(
         self._clock = hs.get_clock()
         self.database_engine = database.engine
 
-        all_users_native = are_all_users_on_domain(
-            db_conn.cursor(), database.engine, hs.hostname
-        )
-        if not all_users_native:
-            raise Exception(
-                "Found users in database not native to %s!\n"
-                "You cannot changed a synapse server_name after it's been configured"
-                % (hs.hostname,)
-            )
-
         self._stream_id_gen = StreamIdGenerator(
             db_conn,
             "events",
@@ -567,13 +558,26 @@ class DataStore(
         )
 
 
-def are_all_users_on_domain(txn, database_engine, domain):
+def check_database_before_upgrade(cur, database_engine, config: HomeServerConfig):
+    """Called before upgrading an existing database to check that it is broadly sane
+    compared with the configuration.
+    """
+    domain = config.server_name
+
     sql = database_engine.convert_param_style(
         "SELECT COUNT(*) FROM users WHERE name NOT LIKE ?"
     )
     pat = "%:" + domain
-    txn.execute(sql, (pat,))
-    num_not_matching = txn.fetchall()[0][0]
+    cur.execute(sql, (pat,))
+    num_not_matching = cur.fetchall()[0][0]
     if num_not_matching == 0:
-        return True
-    return False
+        return
+
+    raise Exception(
+        "Found users in database not native to %s!\n"
+        "You cannot changed a synapse server_name after it's been configured"
+        % (domain,)
+    )
+
+
+__all__ = ["DataStore", "check_database_before_upgrade"]
diff --git a/synapse/storage/data_stores/main/appservice.py b/synapse/storage/data_stores/main/appservice.py
index b2f39649fd..efbc06c796 100644
--- a/synapse/storage/data_stores/main/appservice.py
+++ b/synapse/storage/data_stores/main/appservice.py
@@ -135,7 +135,7 @@ class ApplicationServiceTransactionWorkerStore(
             may be empty.
         """
         results = yield self.db.simple_select_list(
-            "application_services_state", dict(state=state), ["as_id"]
+            "application_services_state", {"state": state}, ["as_id"]
         )
         # NB: This assumes this class is linked with ApplicationServiceStore
         as_list = self.get_app_services()
@@ -158,7 +158,7 @@ class ApplicationServiceTransactionWorkerStore(
         """
         result = yield self.db.simple_select_one(
             "application_services_state",
-            dict(as_id=service.id),
+            {"as_id": service.id},
             ["state"],
             allow_none=True,
             desc="get_appservice_state",
@@ -177,7 +177,7 @@ class ApplicationServiceTransactionWorkerStore(
             A Deferred which resolves when the state was set successfully.
         """
         return self.db.simple_upsert(
-            "application_services_state", dict(as_id=service.id), dict(state=state)
+            "application_services_state", {"as_id": service.id}, {"state": state}
         )
 
     def create_appservice_txn(self, service, events):
@@ -253,13 +253,15 @@ class ApplicationServiceTransactionWorkerStore(
             self.db.simple_upsert_txn(
                 txn,
                 "application_services_state",
-                dict(as_id=service.id),
-                dict(last_txn=txn_id),
+                {"as_id": service.id},
+                {"last_txn": txn_id},
             )
 
             # Delete txn
             self.db.simple_delete_txn(
-                txn, "application_services_txns", dict(txn_id=txn_id, as_id=service.id)
+                txn,
+                "application_services_txns",
+                {"txn_id": txn_id, "as_id": service.id},
             )
 
         return self.db.runInteraction(
diff --git a/synapse/storage/data_stores/main/client_ips.py b/synapse/storage/data_stores/main/client_ips.py
index 73acc162ed..b62755b180 100644
--- a/synapse/storage/data_stores/main/client_ips.py
+++ b/synapse/storage/data_stores/main/client_ips.py
@@ -529,7 +529,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
             ((row["access_token"], row["ip"]), (row["user_agent"], row["last_seen"]))
             for row in rows
         )
-        return list(
+        return [
             {
                 "access_token": access_token,
                 "ip": ip,
@@ -537,7 +537,7 @@ class ClientIpStore(ClientIpBackgroundUpdateStore):
                 "last_seen": last_seen,
             }
             for (access_token, ip), (user_agent, last_seen) in iteritems(results)
-        )
+        ]
 
     @wrap_as_background_process("prune_old_user_ips")
     async def _prune_old_user_ips(self):
diff --git a/synapse/storage/data_stores/main/devices.py b/synapse/storage/data_stores/main/devices.py
index b7617efb80..d55733a4cd 100644
--- a/synapse/storage/data_stores/main/devices.py
+++ b/synapse/storage/data_stores/main/devices.py
@@ -137,7 +137,7 @@ class DeviceWorkerStore(SQLBaseStore):
 
         # get the cross-signing keys of the users in the list, so that we can
         # determine which of the device changes were cross-signing keys
-        users = set(r[0] for r in updates)
+        users = {r[0] for r in updates}
         master_key_by_user = {}
         self_signing_key_by_user = {}
         for user in users:
@@ -446,7 +446,7 @@ class DeviceWorkerStore(SQLBaseStore):
             a set of user_ids and results_map is a mapping of
             user_id -> device_id -> device_info
         """
-        user_ids = set(user_id for user_id, _ in query_list)
+        user_ids = {user_id for user_id, _ in query_list}
         user_map = yield self.get_device_list_last_stream_id_for_remotes(list(user_ids))
 
         # We go and check if any of the users need to have their device lists
@@ -454,10 +454,9 @@ class DeviceWorkerStore(SQLBaseStore):
         users_needing_resync = yield self.get_user_ids_requiring_device_list_resync(
             user_ids
         )
-        user_ids_in_cache = (
-            set(user_id for user_id, stream_id in user_map.items() if stream_id)
-            - users_needing_resync
-        )
+        user_ids_in_cache = {
+            user_id for user_id, stream_id in user_map.items() if stream_id
+        } - users_needing_resync
         user_ids_not_in_cache = user_ids - user_ids_in_cache
 
         results = {}
@@ -604,7 +603,7 @@ class DeviceWorkerStore(SQLBaseStore):
             rows = yield self.db.execute(
                 "get_users_whose_signatures_changed", None, sql, user_id, from_key
             )
-            return set(user for row in rows for user in json.loads(row[0]))
+            return {user for row in rows for user in json.loads(row[0])}
         else:
             return set()
 
diff --git a/synapse/storage/data_stores/main/end_to_end_keys.py b/synapse/storage/data_stores/main/end_to_end_keys.py
index e551606f9d..001a53f9b4 100644
--- a/synapse/storage/data_stores/main/end_to_end_keys.py
+++ b/synapse/storage/data_stores/main/end_to_end_keys.py
@@ -680,11 +680,6 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
                 'user_signing' for a user-signing key
             key (dict): the key data
         """
-        # the cross-signing keys need to occupy the same namespace as devices,
-        # since signatures are identified by device ID.  So add an entry to the
-        # device table to make sure that we don't have a collision with device
-        # IDs
-
         # the 'key' dict will look something like:
         # {
         #   "user_id": "@alice:example.com",
@@ -701,16 +696,24 @@ class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
         # The "keys" property must only have one entry, which will be the public
         # key, so we just grab the first value in there
         pubkey = next(iter(key["keys"].values()))
-        self.db.simple_insert_txn(
-            txn,
-            "devices",
-            values={
-                "user_id": user_id,
-                "device_id": pubkey,
-                "display_name": key_type + " signing key",
-                "hidden": True,
-            },
-        )
+
+        # The cross-signing keys need to occupy the same namespace as devices,
+        # since signatures are identified by device ID.  So add an entry to the
+        # device table to make sure that we don't have a collision with device
+        # IDs.
+        # 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(
+                txn,
+                "devices",
+                values={
+                    "user_id": user_id,
+                    "device_id": pubkey,
+                    "display_name": key_type + " signing key",
+                    "hidden": True,
+                },
+            )
 
         # and finally, store the key itself
         with self._cross_signing_id_gen.get_next() as stream_id:
diff --git a/synapse/storage/data_stores/main/event_federation.py b/synapse/storage/data_stores/main/event_federation.py
index 60c67457b4..49a7b8b433 100644
--- a/synapse/storage/data_stores/main/event_federation.py
+++ b/synapse/storage/data_stores/main/event_federation.py
@@ -14,8 +14,8 @@
 # limitations under the License.
 import itertools
 import logging
+from typing import List, Optional, Set
 
-from six.moves import range
 from six.moves.queue import Empty, PriorityQueue
 
 from twisted.internet import defer
@@ -27,6 +27,7 @@ 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.util.caches.descriptors import cached
+from synapse.util.iterutils import batch_iter
 
 logger = logging.getLogger(__name__)
 
@@ -46,21 +47,37 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
             event_ids, include_given=include_given
         ).addCallback(self.get_events_as_list)
 
-    def get_auth_chain_ids(self, event_ids, include_given=False):
+    def get_auth_chain_ids(
+        self,
+        event_ids: List[str],
+        include_given: bool = False,
+        ignore_events: Optional[Set[str]] = None,
+    ):
         """Get auth events for given event_ids. The events *must* be state events.
 
         Args:
-            event_ids (list): state events
-            include_given (bool): include the given events in result
+            event_ids: state events
+            include_given: include the given events in result
+            ignore_events: Set of events to exclude from the returned auth
+                chain. This is useful if the caller will just discard the
+                given events anyway, and saves us from figuring out their auth
+                chains if not required.
 
         Returns:
             list of event_ids
         """
         return self.db.runInteraction(
-            "get_auth_chain_ids", self._get_auth_chain_ids_txn, event_ids, include_given
+            "get_auth_chain_ids",
+            self._get_auth_chain_ids_txn,
+            event_ids,
+            include_given,
+            ignore_events,
         )
 
-    def _get_auth_chain_ids_txn(self, txn, event_ids, include_given):
+    def _get_auth_chain_ids_txn(self, txn, event_ids, include_given, ignore_events):
+        if ignore_events is None:
+            ignore_events = set()
+
         if include_given:
             results = set(event_ids)
         else:
@@ -71,15 +88,14 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         front = set(event_ids)
         while front:
             new_front = set()
-            front_list = list(front)
-            chunks = [front_list[x : x + 100] for x in range(0, len(front), 100)]
-            for chunk in chunks:
+            for chunk in batch_iter(front, 100):
                 clause, args = make_in_list_sql_clause(
                     txn.database_engine, "event_id", chunk
                 )
-                txn.execute(base_sql + clause, list(args))
-                new_front.update([r[0] for r in txn])
+                txn.execute(base_sql + clause, args)
+                new_front.update(r[0] for r in txn)
 
+            new_front -= ignore_events
             new_front -= results
 
             front = new_front
@@ -410,7 +426,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
                     query, (room_id, event_id, False, limit - len(event_results))
                 )
 
-                new_results = set(t[0] for t in txn) - seen_events
+                new_results = {t[0] for t in txn} - seen_events
 
                 new_front |= new_results
                 seen_events |= new_results
diff --git a/synapse/storage/data_stores/main/events.py b/synapse/storage/data_stores/main/events.py
index c9d0d68c3a..8ae23df00a 100644
--- a/synapse/storage/data_stores/main/events.py
+++ b/synapse/storage/data_stores/main/events.py
@@ -145,7 +145,7 @@ class EventsStore(
             return txn.fetchall()
 
         res = yield self.db.runInteraction("read_forward_extremities", fetch)
-        self._current_forward_extremities_amount = c_counter(list(x[0] for x in res))
+        self._current_forward_extremities_amount = c_counter([x[0] for x in res])
 
     @_retry_on_integrity_error
     @defer.inlineCallbacks
@@ -598,11 +598,11 @@ class EventsStore(
             # We find out which membership events we may have deleted
             # and which we have added, then we invlidate the caches for all
             # those users.
-            members_changed = set(
+            members_changed = {
                 state_key
                 for ev_type, state_key in itertools.chain(to_delete, to_insert)
                 if ev_type == EventTypes.Member
-            )
+            }
 
             for member in members_changed:
                 txn.call_after(
@@ -1615,7 +1615,7 @@ class EventsStore(
         """
         )
 
-        referenced_state_groups = set(sg for sg, in txn)
+        referenced_state_groups = {sg for sg, in txn}
         logger.info(
             "[purge] found %i referenced state groups", len(referenced_state_groups)
         )
diff --git a/synapse/storage/data_stores/main/events_bg_updates.py b/synapse/storage/data_stores/main/events_bg_updates.py
index 5177b71016..f54c8b1ee0 100644
--- a/synapse/storage/data_stores/main/events_bg_updates.py
+++ b/synapse/storage/data_stores/main/events_bg_updates.py
@@ -402,7 +402,7 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
                     keyvalues={},
                     retcols=("room_id",),
                 )
-                room_ids = set(row["room_id"] for row in rows)
+                room_ids = {row["room_id"] for row in rows}
                 for room_id in room_ids:
                     txn.call_after(
                         self.get_latest_event_ids_in_room.invalidate, (room_id,)
diff --git a/synapse/storage/data_stores/main/events_worker.py b/synapse/storage/data_stores/main/events_worker.py
index bf846e6264..3704995bad 100644
--- a/synapse/storage/data_stores/main/events_worker.py
+++ b/synapse/storage/data_stores/main/events_worker.py
@@ -494,9 +494,9 @@ class EventsWorkerStore(SQLBaseStore):
         """
         with Measure(self._clock, "_fetch_event_list"):
             try:
-                events_to_fetch = set(
+                events_to_fetch = {
                     event_id for events, _ in event_list for event_id in events
-                )
+                }
 
                 row_dict = self.db.new_transaction(
                     conn, "do_fetch", [], [], self._fetch_event_rows, events_to_fetch
@@ -804,7 +804,7 @@ class EventsWorkerStore(SQLBaseStore):
             desc="have_events_in_timeline",
         )
 
-        return set(r["event_id"] for r in rows)
+        return {r["event_id"] for r in rows}
 
     @defer.inlineCallbacks
     def have_seen_events(self, event_ids):
diff --git a/synapse/storage/data_stores/main/push_rule.py b/synapse/storage/data_stores/main/push_rule.py
index e2673ae073..62ac88d9f2 100644
--- a/synapse/storage/data_stores/main/push_rule.py
+++ b/synapse/storage/data_stores/main/push_rule.py
@@ -276,21 +276,21 @@ class PushRulesWorkerStore(
         # We ignore app service users for now. This is so that we don't fill
         # up the `get_if_users_have_pushers` cache with AS entries that we
         # know don't have pushers, nor even read receipts.
-        local_users_in_room = set(
+        local_users_in_room = {
             u
             for u in users_in_room
             if self.hs.is_mine_id(u)
             and not self.get_if_app_services_interested_in_user(u)
-        )
+        }
 
         # users in the room who have pushers need to get push rules run because
         # that's how their pushers work
         if_users_with_pushers = yield self.get_if_users_have_pushers(
             local_users_in_room, on_invalidate=cache_context.invalidate
         )
-        user_ids = set(
+        user_ids = {
             uid for uid, have_pusher in if_users_with_pushers.items() if have_pusher
-        )
+        }
 
         users_with_receipts = yield self.get_users_with_read_receipts_in_room(
             room_id, on_invalidate=cache_context.invalidate
diff --git a/synapse/storage/data_stores/main/pusher.py b/synapse/storage/data_stores/main/pusher.py
index 6b03233262..547b9d69cb 100644
--- a/synapse/storage/data_stores/main/pusher.py
+++ b/synapse/storage/data_stores/main/pusher.py
@@ -197,6 +197,84 @@ class PusherWorkerStore(SQLBaseStore):
 
         return result
 
+    @defer.inlineCallbacks
+    def update_pusher_last_stream_ordering(
+        self, app_id, pushkey, user_id, last_stream_ordering
+    ):
+        yield self.db.simple_update_one(
+            "pushers",
+            {"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
+            {"last_stream_ordering": last_stream_ordering},
+            desc="update_pusher_last_stream_ordering",
+        )
+
+    @defer.inlineCallbacks
+    def update_pusher_last_stream_ordering_and_success(
+        self, app_id, pushkey, user_id, last_stream_ordering, last_success
+    ):
+        """Update the last stream ordering position we've processed up to for
+        the given pusher.
+
+        Args:
+            app_id (str)
+            pushkey (str)
+            last_stream_ordering (int)
+            last_success (int)
+
+        Returns:
+            Deferred[bool]: True if the pusher still exists; False if it has been deleted.
+        """
+        updated = yield self.db.simple_update(
+            table="pushers",
+            keyvalues={"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
+            updatevalues={
+                "last_stream_ordering": last_stream_ordering,
+                "last_success": last_success,
+            },
+            desc="update_pusher_last_stream_ordering_and_success",
+        )
+
+        return bool(updated)
+
+    @defer.inlineCallbacks
+    def update_pusher_failing_since(self, app_id, pushkey, user_id, failing_since):
+        yield self.db.simple_update(
+            table="pushers",
+            keyvalues={"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
+            updatevalues={"failing_since": failing_since},
+            desc="update_pusher_failing_since",
+        )
+
+    @defer.inlineCallbacks
+    def get_throttle_params_by_room(self, pusher_id):
+        res = yield self.db.simple_select_list(
+            "pusher_throttle",
+            {"pusher": pusher_id},
+            ["room_id", "last_sent_ts", "throttle_ms"],
+            desc="get_throttle_params_by_room",
+        )
+
+        params_by_room = {}
+        for row in res:
+            params_by_room[row["room_id"]] = {
+                "last_sent_ts": row["last_sent_ts"],
+                "throttle_ms": row["throttle_ms"],
+            }
+
+        return params_by_room
+
+    @defer.inlineCallbacks
+    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(
+            "pusher_throttle",
+            {"pusher": pusher_id, "room_id": room_id},
+            params,
+            desc="set_throttle_params",
+            lock=False,
+        )
+
 
 class PusherStore(PusherWorkerStore):
     def get_pushers_stream_token(self):
@@ -282,81 +360,3 @@ class PusherStore(PusherWorkerStore):
 
         with self._pushers_id_gen.get_next() as stream_id:
             yield self.db.runInteraction("delete_pusher", delete_pusher_txn, stream_id)
-
-    @defer.inlineCallbacks
-    def update_pusher_last_stream_ordering(
-        self, app_id, pushkey, user_id, last_stream_ordering
-    ):
-        yield self.db.simple_update_one(
-            "pushers",
-            {"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
-            {"last_stream_ordering": last_stream_ordering},
-            desc="update_pusher_last_stream_ordering",
-        )
-
-    @defer.inlineCallbacks
-    def update_pusher_last_stream_ordering_and_success(
-        self, app_id, pushkey, user_id, last_stream_ordering, last_success
-    ):
-        """Update the last stream ordering position we've processed up to for
-        the given pusher.
-
-        Args:
-            app_id (str)
-            pushkey (str)
-            last_stream_ordering (int)
-            last_success (int)
-
-        Returns:
-            Deferred[bool]: True if the pusher still exists; False if it has been deleted.
-        """
-        updated = yield self.db.simple_update(
-            table="pushers",
-            keyvalues={"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
-            updatevalues={
-                "last_stream_ordering": last_stream_ordering,
-                "last_success": last_success,
-            },
-            desc="update_pusher_last_stream_ordering_and_success",
-        )
-
-        return bool(updated)
-
-    @defer.inlineCallbacks
-    def update_pusher_failing_since(self, app_id, pushkey, user_id, failing_since):
-        yield self.db.simple_update(
-            table="pushers",
-            keyvalues={"app_id": app_id, "pushkey": pushkey, "user_name": user_id},
-            updatevalues={"failing_since": failing_since},
-            desc="update_pusher_failing_since",
-        )
-
-    @defer.inlineCallbacks
-    def get_throttle_params_by_room(self, pusher_id):
-        res = yield self.db.simple_select_list(
-            "pusher_throttle",
-            {"pusher": pusher_id},
-            ["room_id", "last_sent_ts", "throttle_ms"],
-            desc="get_throttle_params_by_room",
-        )
-
-        params_by_room = {}
-        for row in res:
-            params_by_room[row["room_id"]] = {
-                "last_sent_ts": row["last_sent_ts"],
-                "throttle_ms": row["throttle_ms"],
-            }
-
-        return params_by_room
-
-    @defer.inlineCallbacks
-    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(
-            "pusher_throttle",
-            {"pusher": pusher_id, "room_id": room_id},
-            params,
-            desc="set_throttle_params",
-            lock=False,
-        )
diff --git a/synapse/storage/data_stores/main/receipts.py b/synapse/storage/data_stores/main/receipts.py
index 96e54d145e..0d932a0672 100644
--- a/synapse/storage/data_stores/main/receipts.py
+++ b/synapse/storage/data_stores/main/receipts.py
@@ -58,7 +58,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
     @cachedInlineCallbacks()
     def get_users_with_read_receipts_in_room(self, room_id):
         receipts = yield self.get_receipts_for_room(room_id, "m.read")
-        return set(r["user_id"] for r in receipts)
+        return {r["user_id"] for r in receipts}
 
     @cached(num_args=2)
     def get_receipts_for_room(self, room_id, receipt_type):
@@ -283,7 +283,7 @@ class ReceiptsWorkerStore(SQLBaseStore):
                 args.append(limit)
             txn.execute(sql, args)
 
-            return list(r[0:5] + (json.loads(r[5]),) for r in txn)
+            return [r[0:5] + (json.loads(r[5]),) for r in txn]
 
         return self.db.runInteraction(
             "get_all_updated_receipts", get_all_updated_receipts_txn
diff --git a/synapse/storage/data_stores/main/room.py b/synapse/storage/data_stores/main/room.py
index 9a17e336ba..e6c10c6316 100644
--- a/synapse/storage/data_stores/main/room.py
+++ b/synapse/storage/data_stores/main/room.py
@@ -954,6 +954,23 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
 
         self.config = hs.config
 
+    async def upsert_room_on_join(self, room_id: str, room_version: RoomVersion):
+        """Ensure that the room is stored in the table
+
+        Called when we join a room over federation, and overwrites any room version
+        currently in the table.
+        """
+        await self.db.simple_upsert(
+            desc="upsert_room_on_join",
+            table="rooms",
+            keyvalues={"room_id": room_id},
+            values={"room_version": room_version.identifier},
+            insertion_values={"is_public": False, "creator": ""},
+            # rooms has a unique constraint on room_id, so no need to lock when doing an
+            # emulated upsert.
+            lock=False,
+        )
+
     @defer.inlineCallbacks
     def store_room(
         self,
@@ -1003,6 +1020,26 @@ class RoomStore(RoomBackgroundUpdateStore, RoomWorkerStore, SearchStore):
             logger.error("store_room with room_id=%s failed: %s", room_id, e)
             raise StoreError(500, "Problem creating room.")
 
+    async def maybe_store_room_on_invite(self, room_id: str, room_version: RoomVersion):
+        """
+        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(
+            desc="maybe_store_room_on_invite",
+            table="rooms",
+            keyvalues={"room_id": room_id},
+            values={},
+            insertion_values={
+                "room_version": room_version.identifier,
+                "is_public": False,
+                "creator": "",
+            },
+            # rooms has a unique constraint on room_id, so no need to lock when doing an
+            # emulated upsert.
+            lock=False,
+        )
+
     @defer.inlineCallbacks
     def set_room_is_public(self, room_id, is_public):
         def set_room_is_public_txn(txn, next_id):
diff --git a/synapse/storage/data_stores/main/roommember.py b/synapse/storage/data_stores/main/roommember.py
index 042289f0e0..d5bd0cb5cf 100644
--- a/synapse/storage/data_stores/main/roommember.py
+++ b/synapse/storage/data_stores/main/roommember.py
@@ -465,7 +465,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
 
             txn.execute(sql % (clause,), args)
 
-            return set(row[0] for row in txn)
+            return {row[0] for row in txn}
 
         return await self.db.runInteraction(
             "get_users_server_still_shares_room_with",
@@ -826,7 +826,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
                 GROUP BY room_id, user_id;
             """
             txn.execute(sql, (user_id,))
-            return set(row[0] for row in txn if row[1] == 0)
+            return {row[0] for row in txn if row[1] == 0}
 
         return self.db.runInteraction(
             "get_forgotten_rooms_for_user", _get_forgotten_rooms_for_user_txn
@@ -868,6 +868,37 @@ class RoomMemberWorkerStore(EventsWorkerStore):
             desc="get_membership_from_event_ids",
         )
 
+    async def is_local_host_in_room_ignoring_users(
+        self, room_id: str, ignore_users: Collection[str]
+    ) -> bool:
+        """Check if there are any local users, excluding those in the given
+        list, in the room.
+        """
+
+        clause, args = make_in_list_sql_clause(
+            self.database_engine, "user_id", ignore_users
+        )
+
+        sql = """
+            SELECT 1 FROM local_current_membership
+            WHERE
+                room_id = ? AND membership = ?
+                AND NOT (%s)
+                LIMIT 1
+        """ % (
+            clause,
+        )
+
+        def _is_local_host_in_room_ignoring_users_txn(txn):
+            txn.execute(sql, (room_id, Membership.JOIN, *args))
+
+            return bool(txn.fetchone())
+
+        return await self.db.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):
diff --git a/synapse/storage/data_stores/main/schema/delta/57/delete_old_current_state_events.sql b/synapse/storage/data_stores/main/schema/delta/57/delete_old_current_state_events.sql
index a133d87a19..aec06c8261 100644
--- a/synapse/storage/data_stores/main/schema/delta/57/delete_old_current_state_events.sql
+++ b/synapse/storage/data_stores/main/schema/delta/57/delete_old_current_state_events.sql
@@ -15,5 +15,8 @@
 
 -- Add background update to go and delete current state events for rooms the
 -- server is no longer in.
-INSERT into background_updates (update_name, progress_json)
-    VALUES ('delete_old_current_state_events', '{}');
+--
+-- this relies on the 'membership' column of current_state_events, so make sure
+-- that's populated first!
+INSERT into background_updates (update_name, progress_json, depends_on)
+    VALUES ('delete_old_current_state_events', '{}', 'current_state_events_membership');
diff --git a/synapse/storage/data_stores/main/schema/full_schemas/README.md b/synapse/storage/data_stores/main/schema/full_schemas/README.md
index bbd3f18604..c00f287190 100644
--- a/synapse/storage/data_stores/main/schema/full_schemas/README.md
+++ b/synapse/storage/data_stores/main/schema/full_schemas/README.md
@@ -1,13 +1,21 @@
-# Building full schema dumps
+# Synapse Database Schemas
 
-These schemas need to be made from a database that has had all background updates run.
+These schemas are used as a basis to create brand new Synapse databases, on both
+SQLite3 and Postgres.
 
-To do so, use `scripts-dev/make_full_schema.sh`. This will produce
-`full.sql.postgres ` and `full.sql.sqlite` files.
+## Building full schema dumps
+
+If you want to recreate these schemas, they need to be made from a database that
+has had all background updates run.
+
+To do so, use `scripts-dev/make_full_schema.sh`. This will produce new
+`full.sql.postgres ` and `full.sql.sqlite` files. 
 
 Ensure postgres is installed and your user has the ability to run bash commands
-such as `createdb`.
+such as `createdb`, then call
+
+    ./scripts-dev/make_full_schema.sh -p postgres_username -o output_dir/
 
-```
-./scripts-dev/make_full_schema.sh -p postgres_username -o output_dir/
-```
+There are currently two folders with full-schema snapshots. `16` is a snapshot
+from 2015, for historical reference. The other contains the most recent full
+schema snapshot.
diff --git a/synapse/storage/data_stores/main/state.py b/synapse/storage/data_stores/main/state.py
index 3d34103e67..3a3b9a8e72 100644
--- a/synapse/storage/data_stores/main/state.py
+++ b/synapse/storage/data_stores/main/state.py
@@ -321,7 +321,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             desc="get_referenced_state_groups",
         )
 
-        return set(row["state_group"] for row in rows)
+        return {row["state_group"] for row in rows}
 
 
 class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
@@ -367,7 +367,7 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
             """
 
             txn.execute(sql, (last_room_id, batch_size))
-            room_ids = list(row[0] for row in txn)
+            room_ids = [row[0] for row in txn]
             if not room_ids:
                 return True, set()
 
@@ -384,7 +384,7 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
 
             txn.execute(sql, (last_room_id, room_ids[-1], "%:" + self.server_name))
 
-            joined_room_ids = set(row[0] for row in txn)
+            joined_room_ids = {row[0] for row in txn}
 
             left_rooms = set(room_ids) - joined_room_ids
 
@@ -404,7 +404,7 @@ class MainStateBackgroundUpdateStore(RoomMemberWorkerStore):
                 retcols=("state_key",),
             )
 
-            potentially_left_users = set(row["state_key"] for row in rows)
+            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(
diff --git a/synapse/storage/data_stores/main/stream.py b/synapse/storage/data_stores/main/stream.py
index 056b25b13a..ada5cce6c2 100644
--- a/synapse/storage/data_stores/main/stream.py
+++ b/synapse/storage/data_stores/main/stream.py
@@ -346,11 +346,11 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
             from_key (str): The room_key portion of a StreamToken
         """
         from_key = RoomStreamToken.parse_stream_token(from_key).stream
-        return set(
+        return {
             room_id
             for room_id in room_ids
             if self._events_stream_cache.has_entity_changed(room_id, from_key)
-        )
+        }
 
     @defer.inlineCallbacks
     def get_room_events_stream_for_room(
@@ -679,11 +679,11 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         )
 
         events_before = yield self.get_events_as_list(
-            [e for e in results["before"]["event_ids"]], get_prev_content=True
+            list(results["before"]["event_ids"]), get_prev_content=True
         )
 
         events_after = yield self.get_events_as_list(
-            [e for e in results["after"]["event_ids"]], get_prev_content=True
+            list(results["after"]["event_ids"]), get_prev_content=True
         )
 
         return {
diff --git a/synapse/storage/data_stores/main/user_erasure_store.py b/synapse/storage/data_stores/main/user_erasure_store.py
index af8025bc17..ec6b8a4ffd 100644
--- a/synapse/storage/data_stores/main/user_erasure_store.py
+++ b/synapse/storage/data_stores/main/user_erasure_store.py
@@ -63,9 +63,9 @@ class UserErasureWorkerStore(SQLBaseStore):
             retcols=("user_id",),
             desc="are_users_erased",
         )
-        erased_users = set(row["user_id"] for row in rows)
+        erased_users = {row["user_id"] for row in rows}
 
-        res = dict((u, u in erased_users) for u in user_ids)
+        res = {u: u in erased_users for u in user_ids}
         return res
 
 
diff --git a/synapse/storage/data_stores/state/store.py b/synapse/storage/data_stores/state/store.py
index e4c5b904e1..f3ad1e4369 100644
--- a/synapse/storage/data_stores/state/store.py
+++ b/synapse/storage/data_stores/state/store.py
@@ -518,11 +518,11 @@ class StateGroupDataStore(StateBackgroundUpdateStore, SQLBaseStore):
             retcols=("state_group",),
         )
 
-        remaining_state_groups = set(
+        remaining_state_groups = {
             row["state_group"]
             for row in rows
             if row["state_group"] not in state_groups_to_delete
-        )
+        }
 
         logger.info(
             "[purge] de-delta-ing %i remaining state groups",
diff --git a/synapse/storage/database.py b/synapse/storage/database.py
index 3eeb2f7c04..1953614401 100644
--- a/synapse/storage/database.py
+++ b/synapse/storage/database.py
@@ -554,8 +554,8 @@ class Database(object):
         Returns:
             A list of dicts where the key is the column header.
         """
-        col_headers = list(intern(str(column[0])) for column in cursor.description)
-        results = list(dict(zip(col_headers, row)) for row in cursor)
+        col_headers = [intern(str(column[0])) for column in cursor.description]
+        results = [dict(zip(col_headers, row)) for row in cursor]
         return results
 
     def execute(self, desc, decoder, query, *args):
@@ -1504,7 +1504,7 @@ class Database(object):
 
 def make_in_list_sql_clause(
     database_engine, column: str, iterable: Iterable
-) -> Tuple[str, Iterable]:
+) -> Tuple[str, list]:
     """Returns an SQL clause that checks the given column is in the iterable.
 
     On SQLite this expands to `column IN (?, ?, ...)`, whereas on Postgres
diff --git a/synapse/storage/engines/postgres.py b/synapse/storage/engines/postgres.py
index a077345960..53b3f372b0 100644
--- a/synapse/storage/engines/postgres.py
+++ b/synapse/storage/engines/postgres.py
@@ -53,7 +53,7 @@ class PostgresEngine(object):
             if rows and rows[0][0] != "UTF8":
                 raise IncorrectDatabaseSetup(
                     "Database has incorrect encoding: '%s' instead of 'UTF8'\n"
-                    "See docs/postgres.rst for more information." % (rows[0][0],)
+                    "See docs/postgres.md for more information." % (rows[0][0],)
                 )
 
             txn.execute(
@@ -62,12 +62,16 @@ class PostgresEngine(object):
             collation, ctype = txn.fetchone()
             if collation != "C":
                 logger.warning(
-                    "Database has incorrect collation of %r. Should be 'C'", collation
+                    "Database has incorrect collation of %r. Should be 'C'\n"
+                    "See docs/postgres.md for more information.",
+                    collation,
                 )
 
             if ctype != "C":
                 logger.warning(
-                    "Database has incorrect ctype of %r. Should be 'C'", ctype
+                    "Database has incorrect ctype of %r. Should be 'C'\n"
+                    "See docs/postgres.md for more information.",
+                    ctype,
                 )
 
     def check_new_database(self, txn):
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
index a5370ed527..0f9ac1cf09 100644
--- a/synapse/storage/persist_events.py
+++ b/synapse/storage/persist_events.py
@@ -602,14 +602,14 @@ class EventsPersistenceStorage(object):
             event_id_to_state_group.update(event_to_groups)
 
         # State groups of old_latest_event_ids
-        old_state_groups = set(
+        old_state_groups = {
             event_id_to_state_group[evid] for evid in old_latest_event_ids
-        )
+        }
 
         # State groups of new_latest_event_ids
-        new_state_groups = set(
+        new_state_groups = {
             event_id_to_state_group[evid] for evid in new_latest_event_ids
-        )
+        }
 
         # If they old and new groups are the same then we don't need to do
         # anything.
@@ -727,6 +727,7 @@ class EventsPersistenceStorage(object):
 
         # Check if any of the given events are a local join that appear in the
         # current state
+        events_to_check = []  # Event IDs that aren't an event we're persisting
         for (typ, state_key), event_id in delta.to_insert.items():
             if typ != EventTypes.Member or not self.is_mine_id(state_key):
                 continue
@@ -736,8 +737,33 @@ class EventsPersistenceStorage(object):
                     if event.membership == Membership.JOIN:
                         return True
 
-        # There's been a change of membership but we don't have a local join
-        # event in the new events, so we need to check the full state.
+            # The event is not in `ev_ctx_rm`, so we need to pull it out of
+            # the DB.
+            events_to_check.append(event_id)
+
+        # Check if any of the changes that we don't have events for are joins.
+        if events_to_check:
+            rows = await self.main_store.get_membership_from_event_ids(events_to_check)
+            is_still_joined = any(row["membership"] == Membership.JOIN for row in rows)
+            if is_still_joined:
+                return True
+
+        # None of the new state events are local joins, so we check the database
+        # to see if there are any other local users in the room. We ignore users
+        # whose state has changed as we've already their new state above.
+        users_to_ignore = [
+            state_key
+            for _, state_key in itertools.chain(delta.to_insert, delta.to_delete)
+            if self.is_mine_id(state_key)
+        ]
+
+        if await self.main_store.is_local_host_in_room_ignoring_users(
+            room_id, users_to_ignore
+        ):
+            return True
+
+        # The server will leave the room, so we go and find out which remote
+        # users will still be joined when we leave.
         if current_state is None:
             current_state = await self.main_store.get_current_state_ids(room_id)
             current_state = dict(current_state)
@@ -746,19 +772,6 @@ class EventsPersistenceStorage(object):
 
             current_state.update(delta.to_insert)
 
-        event_ids = [
-            event_id
-            for (typ, state_key,), event_id in current_state.items()
-            if typ == EventTypes.Member and self.is_mine_id(state_key)
-        ]
-
-        rows = await self.main_store.get_membership_from_event_ids(event_ids)
-        is_still_joined = any(row["membership"] == Membership.JOIN for row in rows)
-        if is_still_joined:
-            return True
-
-        # The server will leave the room, so we go and find out which remote
-        # users will still be joined when we leave.
         remote_event_ids = [
             event_id
             for (typ, state_key,), event_id in current_state.items()
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index c285ef52a0..6cb7d4b922 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -278,13 +278,17 @@ def _upgrade_existing_database(
             the current_version wasn't generated by applying those delta files.
         database_engine (DatabaseEngine)
         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
+            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.
         is_empty (bool): Is this a blank database? I.e. do we need to run the
             upgrade portions of the delta scripts.
     """
+    if is_empty:
+        assert not applied_delta_files
+    else:
+        assert config
 
     if current_version > SCHEMA_VERSION:
         raise ValueError(
@@ -292,6 +296,13 @@ def _upgrade_existing_database(
             + "new for the server to understand"
         )
 
+    # 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
+
+        check_database_before_upgrade(cur, database_engine, config)
+
     start_ver = current_version
     if not upgraded:
         start_ver += 1
@@ -345,9 +356,9 @@ def _upgrade_existing_database(
                     "Could not open delta dir for version %d: %s" % (v, directory)
                 )
 
-        duplicates = set(
+        duplicates = {
             file_name for file_name, count in file_name_counter.items() if count > 1
-        )
+        }
         if duplicates:
             # We don't support using the same file name in the same delta version.
             raise PrepareDatabaseException(
@@ -454,7 +465,7 @@ def _apply_module_schema_files(cur, database_engine, modname, names_and_streams)
         ),
         (modname,),
     )
-    applied_deltas = set(d for d, in cur)
+    applied_deltas = {d for d, in cur}
     for (name, stream) in names_and_streams:
         if name in applied_deltas:
             continue
diff --git a/synapse/util/frozenutils.py b/synapse/util/frozenutils.py
index 635b897d6c..f2ccd5e7c6 100644
--- a/synapse/util/frozenutils.py
+++ b/synapse/util/frozenutils.py
@@ -30,7 +30,7 @@ def freeze(o):
         return o
 
     try:
-        return tuple([freeze(i) for i in o])
+        return tuple(freeze(i) for i in o)
     except TypeError:
         pass
 
diff --git a/synapse/visibility.py b/synapse/visibility.py
index d0abd8f04f..e60d9756b7 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -75,7 +75,7 @@ def filter_events_for_client(
     """
     # Filter out events that have been soft failed so that we don't relay them
     # to clients.
-    events = list(e for e in events if not e.internal_metadata.is_soft_failed())
+    events = [e for e in events if not e.internal_metadata.is_soft_failed()]
 
     types = ((EventTypes.RoomHistoryVisibility, ""), (EventTypes.Member, user_id))
     event_id_to_state = yield storage.state.get_state_for_events(
@@ -97,7 +97,7 @@ def filter_events_for_client(
     erased_senders = yield storage.main.are_users_erased((e.sender for e in events))
 
     if apply_retention_policies:
-        room_ids = set(e.room_id for e in events)
+        room_ids = {e.room_id for e in events}
         retention_policies = {}
 
         for room_id in room_ids: