Merge branch 'develop' into rav/url_preview_limit_title

143 files changed, 3109 insertions, 1693 deletions

diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 53f3bb0fa8..5d0b7d2801 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -497,7 +497,7 @@ class Auth(object):
         token = self.get_access_token_from_request(request)
         service = self.store.get_app_service_by_token(token)
         if not service:
-            logger.warn("Unrecognised appservice access token.")
+            logger.warning("Unrecognised appservice access token.")
             raise InvalidClientTokenError()
         request.authenticated_entity = service.sender
         return defer.succeed(service)
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 312196675e..49c4b85054 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -138,3 +138,10 @@ class LimitBlockingTypes(object):
 
     MONTHLY_ACTIVE_USER = "monthly_active_user"
     HS_DISABLED = "hs_disabled"
+
+
+class EventContentFields(object):
+    """Fields found in events' content, regardless of type."""
+
+    # Labels for the event, cf https://github.com/matrix-org/matrix-doc/pull/2326
+    LABELS = "org.matrix.labels"
diff --git a/synapse/api/filtering.py b/synapse/api/filtering.py
index 9f06556bd2..bec13f08d8 100644
--- a/synapse/api/filtering.py
+++ b/synapse/api/filtering.py
@@ -20,6 +20,7 @@ from jsonschema import FormatChecker
 
 from twisted.internet import defer
 
+from synapse.api.constants import EventContentFields
 from synapse.api.errors import SynapseError
 from synapse.storage.presence import UserPresenceState
 from synapse.types import RoomID, UserID
@@ -66,6 +67,10 @@ ROOM_EVENT_FILTER_SCHEMA = {
         "contains_url": {"type": "boolean"},
         "lazy_load_members": {"type": "boolean"},
         "include_redundant_members": {"type": "boolean"},
+        # Include or exclude events with the provided labels.
+        # cf https://github.com/matrix-org/matrix-doc/pull/2326
+        "org.matrix.labels": {"type": "array", "items": {"type": "string"}},
+        "org.matrix.not_labels": {"type": "array", "items": {"type": "string"}},
     },
 }
 
@@ -259,6 +264,9 @@ class Filter(object):
 
         self.contains_url = self.filter_json.get("contains_url", None)
 
+        self.labels = self.filter_json.get("org.matrix.labels", None)
+        self.not_labels = self.filter_json.get("org.matrix.not_labels", [])
+
     def filters_all_types(self):
         return "*" in self.not_types
 
@@ -282,6 +290,7 @@ class Filter(object):
             room_id = None
             ev_type = "m.presence"
             contains_url = False
+            labels = []
         else:
             sender = event.get("sender", None)
             if not sender:
@@ -300,10 +309,11 @@ class Filter(object):
             content = event.get("content", {})
             # check if there is a string url field in the content for filtering purposes
             contains_url = isinstance(content.get("url"), text_type)
+            labels = content.get(EventContentFields.LABELS, [])
 
-        return self.check_fields(room_id, sender, ev_type, contains_url)
+        return self.check_fields(room_id, sender, ev_type, labels, contains_url)
 
-    def check_fields(self, room_id, sender, event_type, contains_url):
+    def check_fields(self, room_id, sender, event_type, labels, contains_url):
         """Checks whether the filter matches the given event fields.
 
         Returns:
@@ -313,6 +323,7 @@ class Filter(object):
             "rooms": lambda v: room_id == v,
             "senders": lambda v: sender == v,
             "types": lambda v: _matches_wildcard(event_type, v),
+            "labels": lambda v: v in labels,
         }
 
         for name, match_func in literal_keys.items():
diff --git a/synapse/app/__init__.py b/synapse/app/__init__.py
index d877c77834..a01bac2997 100644
--- a/synapse/app/__init__.py
+++ b/synapse/app/__init__.py
@@ -44,6 +44,8 @@ def check_bind_error(e, address, bind_addresses):
         bind_addresses (list): Addresses on which the service listens.
     """
     if address == "0.0.0.0" and "::" in bind_addresses:
-        logger.warn("Failed to listen on 0.0.0.0, continuing because listening on [::]")
+        logger.warning(
+            "Failed to listen on 0.0.0.0, continuing because listening on [::]"
+        )
     else:
         raise e
diff --git a/synapse/app/appservice.py b/synapse/app/appservice.py
index 767b87d2db..02b900f382 100644
--- a/synapse/app/appservice.py
+++ b/synapse/app/appservice.py
@@ -94,7 +94,7 @@ class AppserviceServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -103,7 +103,7 @@ class AppserviceServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/client_reader.py b/synapse/app/client_reader.py
index dbcc414c42..dadb487d5f 100644
--- a/synapse/app/client_reader.py
+++ b/synapse/app/client_reader.py
@@ -153,7 +153,7 @@ class ClientReaderServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -162,7 +162,7 @@ class ClientReaderServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/event_creator.py b/synapse/app/event_creator.py
index f20d810ece..d110599a35 100644
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@@ -147,7 +147,7 @@ class EventCreatorServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -156,7 +156,7 @@ class EventCreatorServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/federation_reader.py b/synapse/app/federation_reader.py
index 1ef027a88c..418c086254 100644
--- a/synapse/app/federation_reader.py
+++ b/synapse/app/federation_reader.py
@@ -132,7 +132,7 @@ class FederationReaderServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -141,7 +141,7 @@ class FederationReaderServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/federation_sender.py b/synapse/app/federation_sender.py
index 04fbb407af..139221ad34 100644
--- a/synapse/app/federation_sender.py
+++ b/synapse/app/federation_sender.py
@@ -123,7 +123,7 @@ class FederationSenderServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -132,7 +132,7 @@ class FederationSenderServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/frontend_proxy.py b/synapse/app/frontend_proxy.py
index 9504bfbc70..e647459d0e 100644
--- a/synapse/app/frontend_proxy.py
+++ b/synapse/app/frontend_proxy.py
@@ -204,7 +204,7 @@ class FrontendProxyServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -213,7 +213,7 @@ class FrontendProxyServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index eb54f56853..00a7f8330e 100644
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -19,12 +19,13 @@ from __future__ import print_function
 
 import gc
 import logging
+import math
 import os
+import resource
 import sys
 
 from six import iteritems
 
-import psutil
 from prometheus_client import Gauge
 
 from twisted.application import service
@@ -282,7 +283,7 @@ class SynapseHomeServer(HomeServer):
                     reactor.addSystemEventTrigger("before", "shutdown", s.stopListening)
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -291,7 +292,7 @@ class SynapseHomeServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
     def run_startup_checks(self, db_conn, database_engine):
         all_users_native = are_all_users_on_domain(
@@ -471,6 +472,87 @@ class SynapseService(service.Service):
         return self._port.stopListening()
 
 
+# Contains the list of processes we will be monitoring
+# currently either 0 or 1
+_stats_process = []
+
+
+@defer.inlineCallbacks
+def phone_stats_home(hs, stats, stats_process=_stats_process):
+    logger.info("Gathering stats for reporting")
+    now = int(hs.get_clock().time())
+    uptime = int(now - hs.start_time)
+    if uptime < 0:
+        uptime = 0
+
+    stats["homeserver"] = hs.config.server_name
+    stats["server_context"] = hs.config.server_context
+    stats["timestamp"] = now
+    stats["uptime_seconds"] = uptime
+    version = sys.version_info
+    stats["python_version"] = "{}.{}.{}".format(
+        version.major, version.minor, version.micro
+    )
+    stats["total_users"] = yield hs.get_datastore().count_all_users()
+
+    total_nonbridged_users = yield hs.get_datastore().count_nonbridged_users()
+    stats["total_nonbridged_users"] = total_nonbridged_users
+
+    daily_user_type_results = yield hs.get_datastore().count_daily_user_type()
+    for name, count in iteritems(daily_user_type_results):
+        stats["daily_user_type_" + name] = count
+
+    room_count = yield hs.get_datastore().get_room_count()
+    stats["total_room_count"] = room_count
+
+    stats["daily_active_users"] = yield hs.get_datastore().count_daily_users()
+    stats["monthly_active_users"] = yield hs.get_datastore().count_monthly_users()
+    stats["daily_active_rooms"] = yield hs.get_datastore().count_daily_active_rooms()
+    stats["daily_messages"] = yield hs.get_datastore().count_daily_messages()
+
+    r30_results = yield hs.get_datastore().count_r30_users()
+    for name, count in iteritems(r30_results):
+        stats["r30_users_" + name] = count
+
+    daily_sent_messages = yield hs.get_datastore().count_daily_sent_messages()
+    stats["daily_sent_messages"] = daily_sent_messages
+    stats["cache_factor"] = CACHE_SIZE_FACTOR
+    stats["event_cache_size"] = hs.config.event_cache_size
+
+    #
+    # Performance statistics
+    #
+    old = stats_process[0]
+    new = (now, resource.getrusage(resource.RUSAGE_SELF))
+    stats_process[0] = new
+
+    # Get RSS in bytes
+    stats["memory_rss"] = new[1].ru_maxrss
+
+    # Get CPU time in % of a single core, not % of all cores
+    used_cpu_time = (new[1].ru_utime + new[1].ru_stime) - (
+        old[1].ru_utime + old[1].ru_stime
+    )
+    if used_cpu_time == 0 or new[0] == old[0]:
+        stats["cpu_average"] = 0
+    else:
+        stats["cpu_average"] = math.floor(used_cpu_time / (new[0] - old[0]) * 100)
+
+    #
+    # Database version
+    #
+
+    stats["database_engine"] = hs.get_datastore().database_engine_name
+    stats["database_server_version"] = hs.get_datastore().get_server_version()
+    logger.info("Reporting stats to %s: %s" % (hs.config.report_stats_endpoint, stats))
+    try:
+        yield hs.get_proxied_http_client().put_json(
+            hs.config.report_stats_endpoint, stats
+        )
+    except Exception as e:
+        logger.warning("Error reporting stats: %s", e)
+
+
 def run(hs):
     PROFILE_SYNAPSE = False
     if PROFILE_SYNAPSE:
@@ -497,91 +579,19 @@ def run(hs):
         reactor.run = profile(reactor.run)
 
     clock = hs.get_clock()
-    start_time = clock.time()
 
     stats = {}
 
-    # Contains the list of processes we will be monitoring
-    # currently either 0 or 1
-    stats_process = []
+    def performance_stats_init():
+        _stats_process.clear()
+        _stats_process.append(
+            (int(hs.get_clock().time(), resource.getrusage(resource.RUSAGE_SELF)))
+        )
 
     def start_phone_stats_home():
-        return run_as_background_process("phone_stats_home", phone_stats_home)
-
-    @defer.inlineCallbacks
-    def phone_stats_home():
-        logger.info("Gathering stats for reporting")
-        now = int(hs.get_clock().time())
-        uptime = int(now - start_time)
-        if uptime < 0:
-            uptime = 0
-
-        stats["homeserver"] = hs.config.server_name
-        stats["server_context"] = hs.config.server_context
-        stats["timestamp"] = now
-        stats["uptime_seconds"] = uptime
-        version = sys.version_info
-        stats["python_version"] = "{}.{}.{}".format(
-            version.major, version.minor, version.micro
-        )
-        stats["total_users"] = yield hs.get_datastore().count_all_users()
-
-        total_nonbridged_users = yield hs.get_datastore().count_nonbridged_users()
-        stats["total_nonbridged_users"] = total_nonbridged_users
-
-        daily_user_type_results = yield hs.get_datastore().count_daily_user_type()
-        for name, count in iteritems(daily_user_type_results):
-            stats["daily_user_type_" + name] = count
-
-        room_count = yield hs.get_datastore().get_room_count()
-        stats["total_room_count"] = room_count
-
-        stats["daily_active_users"] = yield hs.get_datastore().count_daily_users()
-        stats["monthly_active_users"] = yield hs.get_datastore().count_monthly_users()
-        stats[
-            "daily_active_rooms"
-        ] = yield hs.get_datastore().count_daily_active_rooms()
-        stats["daily_messages"] = yield hs.get_datastore().count_daily_messages()
-
-        r30_results = yield hs.get_datastore().count_r30_users()
-        for name, count in iteritems(r30_results):
-            stats["r30_users_" + name] = count
-
-        daily_sent_messages = yield hs.get_datastore().count_daily_sent_messages()
-        stats["daily_sent_messages"] = daily_sent_messages
-        stats["cache_factor"] = CACHE_SIZE_FACTOR
-        stats["event_cache_size"] = hs.config.event_cache_size
-
-        if len(stats_process) > 0:
-            stats["memory_rss"] = 0
-            stats["cpu_average"] = 0
-            for process in stats_process:
-                stats["memory_rss"] += process.memory_info().rss
-                stats["cpu_average"] += int(process.cpu_percent(interval=None))
-
-        stats["database_engine"] = hs.get_datastore().database_engine_name
-        stats["database_server_version"] = hs.get_datastore().get_server_version()
-        logger.info(
-            "Reporting stats to %s: %s" % (hs.config.report_stats_endpoint, stats)
+        return run_as_background_process(
+            "phone_stats_home", phone_stats_home, hs, stats
         )
-        try:
-            yield hs.get_simple_http_client().put_json(
-                hs.config.report_stats_endpoint, stats
-            )
-        except Exception as e:
-            logger.warn("Error reporting stats: %s", e)
-
-    def performance_stats_init():
-        try:
-            process = psutil.Process()
-            # Ensure we can fetch both, and make the initial request for cpu_percent
-            # so the next request will use this as the initial point.
-            process.memory_info().rss
-            process.cpu_percent(interval=None)
-            logger.info("report_stats can use psutil")
-            stats_process.append(process)
-        except (AttributeError):
-            logger.warning("Unable to read memory/cpu stats. Disabling reporting.")
 
     def generate_user_daily_visit_stats():
         return run_as_background_process(
@@ -626,7 +636,7 @@ def run(hs):
 
     if hs.config.report_stats:
         logger.info("Scheduling stats reporting for 3 hour intervals")
-        clock.looping_call(start_phone_stats_home, 3 * 60 * 60 * 1000)
+        clock.looping_call(start_phone_stats_home, 3 * 60 * 60 * 1000, hs, stats)
 
         # We need to defer this init for the cases that we daemonize
         # otherwise the process ID we get is that of the non-daemon process
@@ -634,7 +644,7 @@ def run(hs):
 
         # We wait 5 minutes to send the first set of stats as the server can
         # be quite busy the first few minutes
-        clock.call_later(5 * 60, start_phone_stats_home)
+        clock.call_later(5 * 60, start_phone_stats_home, hs, stats)
 
     _base.start_reactor(
         "synapse-homeserver",
diff --git a/synapse/app/media_repository.py b/synapse/app/media_repository.py
index 6bc7202f33..2c6dd3ef02 100644
--- a/synapse/app/media_repository.py
+++ b/synapse/app/media_repository.py
@@ -120,7 +120,7 @@ class MediaRepositoryServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -129,7 +129,7 @@ class MediaRepositoryServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/pusher.py b/synapse/app/pusher.py
index d84732ee3c..01a5ffc363 100644
--- a/synapse/app/pusher.py
+++ b/synapse/app/pusher.py
@@ -114,7 +114,7 @@ class PusherServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -123,7 +123,7 @@ class PusherServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/synchrotron.py b/synapse/app/synchrotron.py
index 6a7e2fa707..b14da09f47 100644
--- a/synapse/app/synchrotron.py
+++ b/synapse/app/synchrotron.py
@@ -326,7 +326,7 @@ class SynchrotronServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -335,7 +335,7 @@ class SynchrotronServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/app/user_dir.py b/synapse/app/user_dir.py
index a5d6dc7915..6cb100319f 100644
--- a/synapse/app/user_dir.py
+++ b/synapse/app/user_dir.py
@@ -150,7 +150,7 @@ class UserDirectoryServer(HomeServer):
                 )
             elif listener["type"] == "metrics":
                 if not self.get_config().enable_metrics:
-                    logger.warn(
+                    logger.warning(
                         (
                             "Metrics listener configured, but "
                             "enable_metrics is not True!"
@@ -159,7 +159,7 @@ class UserDirectoryServer(HomeServer):
                 else:
                     _base.listen_metrics(listener["bind_addresses"], listener["port"])
             else:
-                logger.warn("Unrecognized listener type: %s", listener["type"])
+                logger.warning("Unrecognized listener type: %s", listener["type"])
 
         self.get_tcp_replication().start_replication(self)
 
diff --git a/synapse/appservice/__init__.py b/synapse/appservice/__init__.py
index 33b3579425..aea3985a5f 100644
--- a/synapse/appservice/__init__.py
+++ b/synapse/appservice/__init__.py
@@ -94,7 +94,9 @@ class ApplicationService(object):
         ip_range_whitelist=None,
     ):
         self.token = token
-        self.url = url
+        self.url = (
+            url.rstrip("/") if isinstance(url, str) else None
+        )  # url must not end with a slash
         self.hs_token = hs_token
         self.sender = sender
         self.server_name = hostname
diff --git a/synapse/config/key.py b/synapse/config/key.py
index ec5d430afb..52ff1b2621 100644
--- a/synapse/config/key.py
+++ b/synapse/config/key.py
@@ -125,7 +125,7 @@ class KeyConfig(Config):
 
         # if neither trusted_key_servers nor perspectives are given, use the default.
         if "perspectives" not in config and "trusted_key_servers" not in config:
-            logger.warn(TRUSTED_KEY_SERVER_NOT_CONFIGURED_WARN)
+            logger.warning(TRUSTED_KEY_SERVER_NOT_CONFIGURED_WARN)
             key_servers = [{"server_name": "matrix.org"}]
         else:
             key_servers = config.get("trusted_key_servers", [])
@@ -156,7 +156,7 @@ class KeyConfig(Config):
         if not self.macaroon_secret_key:
             # Unfortunately, there are people out there that don't have this
             # set. Lets just be "nice" and derive one from their secret key.
-            logger.warn("Config is missing macaroon_secret_key")
+            logger.warning("Config is missing macaroon_secret_key")
             seed = bytes(self.signing_key[0])
             self.macaroon_secret_key = hashlib.sha256(seed).digest()
 
diff --git a/synapse/config/logger.py b/synapse/config/logger.py
index be92e33f93..75bb904718 100644
--- a/synapse/config/logger.py
+++ b/synapse/config/logger.py
@@ -182,7 +182,7 @@ def _reload_stdlib_logging(*args, log_config=None):
     logger = logging.getLogger("")
 
     if not log_config:
-        logger.warn("Reloaded a blank config?")
+        logger.warning("Reloaded a blank config?")
 
     logging.config.dictConfig(log_config)
 
@@ -234,8 +234,8 @@ def setup_logging(
 
     # make sure that the first thing we log is a thing we can grep backwards
     # for
-    logging.warn("***** STARTING SERVER *****")
-    logging.warn("Server %s version %s", sys.argv[0], get_version_string(synapse))
+    logging.warning("***** STARTING SERVER *****")
+    logging.warning("Server %s version %s", sys.argv[0], get_version_string(synapse))
     logging.info("Server hostname: %s", config.server_name)
 
     return logger
diff --git a/synapse/config/registration.py b/synapse/config/registration.py
index ab41623b2b..1f6dac69da 100644
--- a/synapse/config/registration.py
+++ b/synapse/config/registration.py
@@ -300,7 +300,7 @@ class RegistrationConfig(Config):
         # If a delegate is specified, the config option public_baseurl must also be filled out.
         #
         account_threepid_delegates:
-            #email: https://example.com     # Delegate email sending to example.org
+            #email: https://example.com     # Delegate email sending to example.com
             #msisdn: http://localhost:8090  # Delegate SMS sending to this local process
 
         # Users who register on this homeserver will automatically be joined
diff --git a/synapse/crypto/event_signing.py b/synapse/crypto/event_signing.py
index 694fb2c816..ccaa8a9920 100644
--- a/synapse/crypto/event_signing.py
+++ b/synapse/crypto/event_signing.py
@@ -125,9 +125,11 @@ def compute_event_signature(event_dict, signature_name, signing_key):
     redact_json = prune_event_dict(event_dict)
     redact_json.pop("age_ts", None)
     redact_json.pop("unsigned", None)
-    logger.debug("Signing event: %s", encode_canonical_json(redact_json))
+    if logger.isEnabledFor(logging.DEBUG):
+        logger.debug("Signing event: %s", encode_canonical_json(redact_json))
     redact_json = sign_json(redact_json, signature_name, signing_key)
-    logger.debug("Signed event: %s", encode_canonical_json(redact_json))
+    if logger.isEnabledFor(logging.DEBUG):
+        logger.debug("Signed event: %s", encode_canonical_json(redact_json))
     return redact_json["signatures"]
 
 
diff --git a/synapse/event_auth.py b/synapse/event_auth.py
index e7b722547b..ec3243b27b 100644
--- a/synapse/event_auth.py
+++ b/synapse/event_auth.py
@@ -77,7 +77,7 @@ def check(room_version, event, auth_events, do_sig_check=True, do_size_check=Tru
     if auth_events is None:
         # Oh, we don't know what the state of the room was, so we
         # are trusting that this is allowed (at least for now)
-        logger.warn("Trusting event: %s", event.event_id)
+        logger.warning("Trusting event: %s", event.event_id)
         return
 
     if event.type == EventTypes.Create:
diff --git a/synapse/events/snapshot.py b/synapse/events/snapshot.py
index acbcbeeced..5f07f6fe4b 100644
--- a/synapse/events/snapshot.py
+++ b/synapse/events/snapshot.py
@@ -12,104 +12,103 @@
 # 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.
+from typing import Dict, Optional, Tuple, Union
 
 from six import iteritems
 
+import attr
 from frozendict import frozendict
 
 from twisted.internet import defer
 
+from synapse.appservice import ApplicationService
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 
 
-class EventContext(object):
+@attr.s(slots=True)
+class EventContext:
     """
+    Holds information relevant to persisting an event
+
     Attributes:
-        state_group (int|None): state group id, if the state has been stored
-            as a state group. This is usually only None if e.g. the event is
-            an outlier.
-        rejected (bool|str): A rejection reason if the event was rejected, else
-            False
-
-        push_actions (list[(str, list[object])]): list of (user_id, actions)
-            tuples
-
-        prev_group (int): Previously persisted state group. ``None`` for an
-            outlier.
-        delta_ids (dict[(str, str), str]): Delta from ``prev_group``.
-            (type, state_key) -> event_id. ``None`` for an outlier.
-
-        prev_state_events (?): XXX: is this ever set to anything other than
-            the empty list?
-
-        _current_state_ids (dict[(str, str), str]|None):
-            The current state map including the current event. None if outlier
-            or we haven't fetched the state from DB yet.
-            (type, state_key) -> event_id
+        rejected: A rejection reason if the event was rejected, else False
+
+        state_group: The ID of the state group for this event. Note that state events
+            are persisted with a state group which includes the new event, so this is
+            effectively the state *after* the event in question.
+
+            For a *rejected* state event, where the state of the rejected event is
+            ignored, this state_group should never make it into the
+            event_to_state_groups table. Indeed, inspecting this value for a rejected
+            state event is almost certainly incorrect.
+
+            For an outlier, where we don't have the state at the event, this will be
+            None.
+
+        prev_group: If it is known, ``state_group``'s prev_group. Note that this being
+            None does not necessarily mean that ``state_group`` does not have
+            a prev_group!
+
+            If ``state_group`` is None (ie, the event is an outlier), ``prev_group``
+            will always also be ``None``.
+
+            Note that this *not* (necessarily) the state group associated with
+            ``_prev_state_ids``.
+
+        delta_ids: If ``prev_group`` is not None, the state delta between ``prev_group``
+            and ``state_group``.
+
+        app_service: If this event is being sent by a (local) application service, that
+            app service.
+
+        _current_state_ids: The room state map, including this event - ie, the state
+            in ``state_group``.
 
-        _prev_state_ids (dict[(str, str), str]|None):
-            The current state map excluding the current event. None if outlier
-            or we haven't fetched the state from DB yet.
             (type, state_key) -> event_id
 
-        _fetching_state_deferred (Deferred|None): Resolves when *_state_ids have
-            been calculated. None if we haven't started calculating yet
+            FIXME: what is this for an outlier? it seems ill-defined. It seems like
+            it could be either {}, or the state we were given by the remote
+            server, depending on $THINGS
 
-        _event_type (str): The type of the event the context is associated with.
-            Only set when state has not been fetched yet.
+            Note that this is a private attribute: it should be accessed via
+            ``get_current_state_ids``. _AsyncEventContext impl calculates this
+            on-demand: it will be None until that happens.
 
-        _event_state_key (str|None): The state_key of the event the context is
-            associated with. Only set when state has not been fetched yet.
+        _prev_state_ids: The room state map, excluding this event. For a non-state
+            event, this will be the same as _current_state_events.
 
-        _prev_state_id (str|None): If the event associated with the context is
-            a state event, then `_prev_state_id` is the event_id of the state
-            that was replaced.
-            Only set when state has not been fetched yet.
+            Note that it is a completely different thing to prev_group!
+
+            (type, state_key) -> event_id
+
+            FIXME: again, what is this for an outlier?
+
+            As with _current_state_ids, this is a private attribute. It should be
+            accessed via get_prev_state_ids.
     """
 
-    __slots__ = [
-        "state_group",
-        "rejected",
-        "prev_group",
-        "delta_ids",
-        "prev_state_events",
-        "app_service",
-        "_current_state_ids",
-        "_prev_state_ids",
-        "_prev_state_id",
-        "_event_type",
-        "_event_state_key",
-        "_fetching_state_deferred",
-    ]
-
-    def __init__(self):
-        self.prev_state_events = []
-        self.rejected = False
-        self.app_service = None
+    rejected = attr.ib(default=False, type=Union[bool, str])
+    state_group = attr.ib(default=None, type=Optional[int])
+    prev_group = attr.ib(default=None, type=Optional[int])
+    delta_ids = attr.ib(default=None, type=Optional[Dict[Tuple[str, str], str]])
+    app_service = attr.ib(default=None, type=Optional[ApplicationService])
+
+    _current_state_ids = attr.ib(
+        default=None, type=Optional[Dict[Tuple[str, str], str]]
+    )
+    _prev_state_ids = attr.ib(default=None, type=Optional[Dict[Tuple[str, str], str]])
 
     @staticmethod
     def with_state(
         state_group, current_state_ids, prev_state_ids, prev_group=None, delta_ids=None
     ):
-        context = EventContext()
-
-        # The current state including the current event
-        context._current_state_ids = current_state_ids
-        # The current state excluding the current event
-        context._prev_state_ids = prev_state_ids
-        context.state_group = state_group
-
-        context._prev_state_id = None
-        context._event_type = None
-        context._event_state_key = None
-        context._fetching_state_deferred = defer.succeed(None)
-
-        # A previously persisted state group and a delta between that
-        # and this state.
-        context.prev_group = prev_group
-        context.delta_ids = delta_ids
-
-        return context
+        return EventContext(
+            current_state_ids=current_state_ids,
+            prev_state_ids=prev_state_ids,
+            state_group=state_group,
+            prev_group=prev_group,
+            delta_ids=delta_ids,
+        )
 
     @defer.inlineCallbacks
     def serialize(self, event, store):
@@ -141,7 +140,6 @@ class EventContext(object):
             "rejected": self.rejected,
             "prev_group": self.prev_group,
             "delta_ids": _encode_state_dict(self.delta_ids),
-            "prev_state_events": self.prev_state_events,
             "app_service_id": self.app_service.id if self.app_service else None,
         }
 
@@ -157,24 +155,17 @@ class EventContext(object):
         Returns:
             EventContext
         """
-        context = EventContext()
-
-        # We use the state_group and prev_state_id stuff to pull the
-        # current_state_ids out of the DB and construct prev_state_ids.
-        context._prev_state_id = input["prev_state_id"]
-        context._event_type = input["event_type"]
-        context._event_state_key = input["event_state_key"]
-
-        context._current_state_ids = None
-        context._prev_state_ids = None
-        context._fetching_state_deferred = None
-
-        context.state_group = input["state_group"]
-        context.prev_group = input["prev_group"]
-        context.delta_ids = _decode_state_dict(input["delta_ids"])
-
-        context.rejected = input["rejected"]
-        context.prev_state_events = input["prev_state_events"]
+        context = _AsyncEventContextImpl(
+            # We use the state_group and prev_state_id stuff to pull the
+            # current_state_ids out of the DB and construct prev_state_ids.
+            prev_state_id=input["prev_state_id"],
+            event_type=input["event_type"],
+            event_state_key=input["event_state_key"],
+            state_group=input["state_group"],
+            prev_group=input["prev_group"],
+            delta_ids=_decode_state_dict(input["delta_ids"]),
+            rejected=input["rejected"],
+        )
 
         app_service_id = input["app_service_id"]
         if app_service_id:
@@ -192,14 +183,7 @@ class EventContext(object):
                 Maps a (type, state_key) to the event ID of the state event matching
                 this tuple.
         """
-
-        if not self._fetching_state_deferred:
-            self._fetching_state_deferred = run_in_background(
-                self._fill_out_state, store
-            )
-
-        yield make_deferred_yieldable(self._fetching_state_deferred)
-
+        yield self._ensure_fetched(store)
         return self._current_state_ids
 
     @defer.inlineCallbacks
@@ -212,14 +196,7 @@ class EventContext(object):
                 Maps a (type, state_key) to the event ID of the state event matching
                 this tuple.
         """
-
-        if not self._fetching_state_deferred:
-            self._fetching_state_deferred = run_in_background(
-                self._fill_out_state, store
-            )
-
-        yield make_deferred_yieldable(self._fetching_state_deferred)
-
+        yield self._ensure_fetched(store)
         return self._prev_state_ids
 
     def get_cached_current_state_ids(self):
@@ -233,6 +210,44 @@ class EventContext(object):
 
         return self._current_state_ids
 
+    def _ensure_fetched(self, store):
+        return defer.succeed(None)
+
+
+@attr.s(slots=True)
+class _AsyncEventContextImpl(EventContext):
+    """
+    An implementation of EventContext which fetches _current_state_ids and
+    _prev_state_ids from the database on demand.
+
+    Attributes:
+
+        _fetching_state_deferred (Deferred|None): Resolves when *_state_ids have
+            been calculated. None if we haven't started calculating yet
+
+        _event_type (str): The type of the event the context is associated with.
+
+        _event_state_key (str): The state_key of the event the context is
+            associated with.
+
+        _prev_state_id (str|None): If the event associated with the context is
+            a state event, then `_prev_state_id` is the event_id of the state
+            that was replaced.
+    """
+
+    _prev_state_id = attr.ib(default=None)
+    _event_type = attr.ib(default=None)
+    _event_state_key = attr.ib(default=None)
+    _fetching_state_deferred = attr.ib(default=None)
+
+    def _ensure_fetched(self, store):
+        if not self._fetching_state_deferred:
+            self._fetching_state_deferred = run_in_background(
+                self._fill_out_state, store
+            )
+
+        return make_deferred_yieldable(self._fetching_state_deferred)
+
     @defer.inlineCallbacks
     def _fill_out_state(self, store):
         """Called to populate the _current_state_ids and _prev_state_ids
@@ -250,27 +265,6 @@ class EventContext(object):
         else:
             self._prev_state_ids = self._current_state_ids
 
-    @defer.inlineCallbacks
-    def update_state(
-        self, state_group, prev_state_ids, current_state_ids, prev_group, delta_ids
-    ):
-        """Replace the state in the context
-        """
-
-        # We need to make sure we wait for any ongoing fetching of state
-        # to complete so that the updated state doesn't get clobbered
-        if self._fetching_state_deferred:
-            yield make_deferred_yieldable(self._fetching_state_deferred)
-
-        self.state_group = state_group
-        self._prev_state_ids = prev_state_ids
-        self.prev_group = prev_group
-        self._current_state_ids = current_state_ids
-        self.delta_ids = delta_ids
-
-        # We need to ensure that that we've marked as having fetched the state
-        self._fetching_state_deferred = defer.succeed(None)
-
 
 def _encode_state_dict(state_dict):
     """Since dicts of (type, state_key) -> event_id cannot be serialized in
diff --git a/synapse/events/spamcheck.py b/synapse/events/spamcheck.py
index 129771f183..5a907718d6 100644
--- a/synapse/events/spamcheck.py
+++ b/synapse/events/spamcheck.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2017 New Vector Ltd
+# Copyright 2019 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.
@@ -13,6 +14,10 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import inspect
+
+from synapse.spam_checker_api import SpamCheckerApi
+
 
 class SpamChecker(object):
     def __init__(self, hs):
@@ -26,7 +31,14 @@ class SpamChecker(object):
             pass
 
         if module is not None:
-            self.spam_checker = module(config=config)
+            # Older spam checkers don't accept the `api` argument, so we
+            # try and detect support.
+            spam_args = inspect.getfullargspec(module)
+            if "api" in spam_args.args:
+                api = SpamCheckerApi(hs)
+                self.spam_checker = module(config=config, api=api)
+            else:
+                self.spam_checker = module(config=config)
 
     def check_event_for_spam(self, event):
         """Checks if a given event is considered "spammy" by this server.
diff --git a/synapse/federation/federation_base.py b/synapse/federation/federation_base.py
index 223aace0d9..0e22183280 100644
--- a/synapse/federation/federation_base.py
+++ b/synapse/federation/federation_base.py
@@ -102,7 +102,7 @@ class FederationBase(object):
                     pass
 
             if not res:
-                logger.warn(
+                logger.warning(
                     "Failed to find copy of %s with valid signature", pdu.event_id
                 )
 
@@ -173,7 +173,7 @@ class FederationBase(object):
                     return redacted_event
 
                 if self.spam_checker.check_event_for_spam(pdu):
-                    logger.warn(
+                    logger.warning(
                         "Event contains spam, redacting %s: %s",
                         pdu.event_id,
                         pdu.get_pdu_json(),
@@ -185,7 +185,7 @@ class FederationBase(object):
         def errback(failure, pdu):
             failure.trap(SynapseError)
             with PreserveLoggingContext(ctx):
-                logger.warn(
+                logger.warning(
                     "Signature check failed for %s: %s",
                     pdu.event_id,
                     failure.getErrorMessage(),
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index 5b22a39b7f..545d719652 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -196,7 +196,7 @@ class FederationClient(FederationBase):
             dest, room_id, extremities, limit
         )
 
-        logger.debug("backfill transaction_data=%s", repr(transaction_data))
+        logger.debug("backfill transaction_data=%r", transaction_data)
 
         room_version = yield self.store.get_room_version(room_id)
         format_ver = room_version_to_event_format(room_version)
@@ -522,12 +522,12 @@ class FederationClient(FederationBase):
                 res = yield callback(destination)
                 return res
             except InvalidResponseError as e:
-                logger.warn("Failed to %s via %s: %s", description, destination, e)
+                logger.warning("Failed to %s via %s: %s", description, destination, e)
             except HttpResponseException as e:
                 if not 500 <= e.code < 600:
                     raise e.to_synapse_error()
                 else:
-                    logger.warn(
+                    logger.warning(
                         "Failed to %s via %s: %i %s",
                         description,
                         destination,
@@ -535,7 +535,9 @@ class FederationClient(FederationBase):
                         e.args[0],
                     )
             except Exception:
-                logger.warn("Failed to %s via %s", description, destination, exc_info=1)
+                logger.warning(
+                    "Failed to %s via %s", description, destination, exc_info=1
+                )
 
         raise SynapseError(502, "Failed to %s via any server" % (description,))
 
@@ -553,7 +555,7 @@ class FederationClient(FederationBase):
         Note that this does not append any events to any graphs.
 
         Args:
-            destinations (str): Candidate homeservers which are probably
+            destinations (Iterable[str]): Candidate homeservers which are probably
                 participating in the room.
             room_id (str): The room in which the event will happen.
             user_id (str): The user whose membership is being evented.
diff --git a/synapse/federation/federation_server.py b/synapse/federation/federation_server.py
index 5fc7c1d67b..d942d77a72 100644
--- a/synapse/federation/federation_server.py
+++ b/synapse/federation/federation_server.py
@@ -21,7 +21,6 @@ from six import iteritems
 from canonicaljson import json
 from prometheus_client import Counter
 
-from twisted.internet import defer
 from twisted.internet.abstract import isIPAddress
 from twisted.python import failure
 
@@ -86,14 +85,12 @@ class FederationServer(FederationBase):
         # come in waves.
         self._state_resp_cache = ResponseCache(hs, "state_resp", timeout_ms=30000)
 
-    @defer.inlineCallbacks
-    @log_function
-    def on_backfill_request(self, origin, room_id, versions, limit):
-        with (yield self._server_linearizer.queue((origin, room_id))):
+    async def on_backfill_request(self, origin, room_id, versions, limit):
+        with (await self._server_linearizer.queue((origin, room_id))):
             origin_host, _ = parse_server_name(origin)
-            yield self.check_server_matches_acl(origin_host, room_id)
+            await self.check_server_matches_acl(origin_host, room_id)
 
-            pdus = yield self.handler.on_backfill_request(
+            pdus = await self.handler.on_backfill_request(
                 origin, room_id, versions, limit
             )
 
@@ -101,9 +98,7 @@ class FederationServer(FederationBase):
 
         return 200, res
 
-    @defer.inlineCallbacks
-    @log_function
-    def on_incoming_transaction(self, origin, transaction_data):
+    async def on_incoming_transaction(self, origin, transaction_data):
         # keep this as early as possible to make the calculated origin ts as
         # accurate as possible.
         request_time = self._clock.time_msec()
@@ -118,18 +113,17 @@ class FederationServer(FederationBase):
         # use a linearizer to ensure that we don't process the same transaction
         # multiple times in parallel.
         with (
-            yield self._transaction_linearizer.queue(
+            await self._transaction_linearizer.queue(
                 (origin, transaction.transaction_id)
             )
         ):
-            result = yield self._handle_incoming_transaction(
+            result = await self._handle_incoming_transaction(
                 origin, transaction, request_time
             )
 
         return result
 
-    @defer.inlineCallbacks
-    def _handle_incoming_transaction(self, origin, transaction, request_time):
+    async def _handle_incoming_transaction(self, origin, transaction, request_time):
         """ Process an incoming transaction and return the HTTP response
 
         Args:
@@ -140,7 +134,7 @@ class FederationServer(FederationBase):
         Returns:
             Deferred[(int, object)]: http response code and body
         """
-        response = yield self.transaction_actions.have_responded(origin, transaction)
+        response = await self.transaction_actions.have_responded(origin, transaction)
 
         if response:
             logger.debug(
@@ -151,7 +145,7 @@ class FederationServer(FederationBase):
 
         logger.debug("[%s] Transaction is new", transaction.transaction_id)
 
-        # Reject if PDU count > 50 and EDU count > 100
+        # Reject if PDU count > 50 or EDU count > 100
         if len(transaction.pdus) > 50 or (
             hasattr(transaction, "edus") and len(transaction.edus) > 100
         ):
@@ -159,7 +153,7 @@ class FederationServer(FederationBase):
             logger.info("Transaction PDU or EDU count too large. Returning 400")
 
             response = {}
-            yield self.transaction_actions.set_response(
+            await self.transaction_actions.set_response(
                 origin, transaction, 400, response
             )
             return 400, response
@@ -195,7 +189,7 @@ class FederationServer(FederationBase):
                 continue
 
             try:
-                room_version = yield self.store.get_room_version(room_id)
+                room_version = await self.store.get_room_version(room_id)
             except NotFoundError:
                 logger.info("Ignoring PDU for unknown room_id: %s", room_id)
                 continue
@@ -221,13 +215,12 @@ class FederationServer(FederationBase):
         # require callouts to other servers to fetch missing events), but
         # impose a limit to avoid going too crazy with ram/cpu.
 
-        @defer.inlineCallbacks
-        def process_pdus_for_room(room_id):
+        async def process_pdus_for_room(room_id):
             logger.debug("Processing PDUs for %s", room_id)
             try:
-                yield self.check_server_matches_acl(origin_host, room_id)
+                await self.check_server_matches_acl(origin_host, room_id)
             except AuthError as e:
-                logger.warn("Ignoring PDUs for room %s from banned server", room_id)
+                logger.warning("Ignoring PDUs for room %s from banned server", room_id)
                 for pdu in pdus_by_room[room_id]:
                     event_id = pdu.event_id
                     pdu_results[event_id] = e.error_dict()
@@ -237,10 +230,10 @@ class FederationServer(FederationBase):
                 event_id = pdu.event_id
                 with nested_logging_context(event_id):
                     try:
-                        yield self._handle_received_pdu(origin, pdu)
+                        await self._handle_received_pdu(origin, pdu)
                         pdu_results[event_id] = {}
                     except FederationError as e:
-                        logger.warn("Error handling PDU %s: %s", event_id, e)
+                        logger.warning("Error handling PDU %s: %s", event_id, e)
                         pdu_results[event_id] = {"error": str(e)}
                     except Exception as e:
                         f = failure.Failure()
@@ -251,36 +244,33 @@ class FederationServer(FederationBase):
                             exc_info=(f.type, f.value, f.getTracebackObject()),
                         )
 
-        yield concurrently_execute(
+        await concurrently_execute(
             process_pdus_for_room, pdus_by_room.keys(), TRANSACTION_CONCURRENCY_LIMIT
         )
 
         if hasattr(transaction, "edus"):
             for edu in (Edu(**x) for x in transaction.edus):
-                yield self.received_edu(origin, edu.edu_type, edu.content)
+                await self.received_edu(origin, edu.edu_type, edu.content)
 
         response = {"pdus": pdu_results}
 
         logger.debug("Returning: %s", str(response))
 
-        yield self.transaction_actions.set_response(origin, transaction, 200, response)
+        await self.transaction_actions.set_response(origin, transaction, 200, response)
         return 200, response
 
-    @defer.inlineCallbacks
-    def received_edu(self, origin, edu_type, content):
+    async def received_edu(self, origin, edu_type, content):
         received_edus_counter.inc()
-        yield self.registry.on_edu(edu_type, origin, content)
+        await self.registry.on_edu(edu_type, origin, content)
 
-    @defer.inlineCallbacks
-    @log_function
-    def on_context_state_request(self, origin, room_id, event_id):
+    async def on_context_state_request(self, origin, room_id, event_id):
         if not event_id:
             raise NotImplementedError("Specify an event")
 
         origin_host, _ = parse_server_name(origin)
-        yield self.check_server_matches_acl(origin_host, room_id)
+        await self.check_server_matches_acl(origin_host, room_id)
 
-        in_room = yield self.auth.check_host_in_room(room_id, origin)
+        in_room = await self.auth.check_host_in_room(room_id, origin)
         if not in_room:
             raise AuthError(403, "Host not in room.")
 
@@ -289,8 +279,8 @@ class FederationServer(FederationBase):
         # in the cache so we could return it without waiting for the linearizer
         # - but that's non-trivial to get right, and anyway somewhat defeats
         # the point of the linearizer.
-        with (yield self._server_linearizer.queue((origin, room_id))):
-            resp = yield self._state_resp_cache.wrap(
+        with (await self._server_linearizer.queue((origin, room_id))):
+            resp = await self._state_resp_cache.wrap(
                 (room_id, event_id),
                 self._on_context_state_request_compute,
                 room_id,
@@ -299,65 +289,60 @@ class FederationServer(FederationBase):
 
         return 200, resp
 
-    @defer.inlineCallbacks
-    def on_state_ids_request(self, origin, room_id, event_id):
+    async def on_state_ids_request(self, origin, room_id, event_id):
         if not event_id:
             raise NotImplementedError("Specify an event")
 
         origin_host, _ = parse_server_name(origin)
-        yield self.check_server_matches_acl(origin_host, room_id)
+        await self.check_server_matches_acl(origin_host, room_id)
 
-        in_room = yield self.auth.check_host_in_room(room_id, origin)
+        in_room = await self.auth.check_host_in_room(room_id, origin)
         if not in_room:
             raise AuthError(403, "Host not in room.")
 
-        state_ids = yield self.handler.get_state_ids_for_pdu(room_id, event_id)
-        auth_chain_ids = yield self.store.get_auth_chain_ids(state_ids)
+        state_ids = await self.handler.get_state_ids_for_pdu(room_id, event_id)
+        auth_chain_ids = await self.store.get_auth_chain_ids(state_ids)
 
         return 200, {"pdu_ids": state_ids, "auth_chain_ids": auth_chain_ids}
 
-    @defer.inlineCallbacks
-    def _on_context_state_request_compute(self, room_id, event_id):
-        pdus = yield self.handler.get_state_for_pdu(room_id, event_id)
-        auth_chain = yield self.store.get_auth_chain([pdu.event_id for pdu in pdus])
+    async def _on_context_state_request_compute(self, room_id, event_id):
+        pdus = await self.handler.get_state_for_pdu(room_id, event_id)
+        auth_chain = await self.store.get_auth_chain([pdu.event_id for pdu in pdus])
 
         return {
             "pdus": [pdu.get_pdu_json() for pdu in pdus],
             "auth_chain": [pdu.get_pdu_json() for pdu in auth_chain],
         }
 
-    @defer.inlineCallbacks
-    @log_function
-    def on_pdu_request(self, origin, event_id):
-        pdu = yield self.handler.get_persisted_pdu(origin, event_id)
+    async def on_pdu_request(self, origin, event_id):
+        pdu = await self.handler.get_persisted_pdu(origin, event_id)
 
         if pdu:
             return 200, self._transaction_from_pdus([pdu]).get_dict()
         else:
             return 404, ""
 
-    @defer.inlineCallbacks
-    def on_query_request(self, query_type, args):
+    async def on_query_request(self, query_type, args):
         received_queries_counter.labels(query_type).inc()
-        resp = yield self.registry.on_query(query_type, args)
+        resp = await self.registry.on_query(query_type, args)
         return 200, resp
 
-    @defer.inlineCallbacks
-    def on_make_join_request(self, origin, room_id, user_id, supported_versions):
+    async def on_make_join_request(self, origin, room_id, user_id, supported_versions):
         origin_host, _ = parse_server_name(origin)
-        yield self.check_server_matches_acl(origin_host, room_id)
+        await self.check_server_matches_acl(origin_host, room_id)
 
-        room_version = yield self.store.get_room_version(room_id)
+        room_version = await self.store.get_room_version(room_id)
         if room_version not in supported_versions:
-            logger.warn("Room version %s not in %s", room_version, supported_versions)
+            logger.warning(
+                "Room version %s not in %s", room_version, supported_versions
+            )
             raise IncompatibleRoomVersionError(room_version=room_version)
 
-        pdu = yield self.handler.on_make_join_request(origin, room_id, user_id)
+        pdu = await self.handler.on_make_join_request(origin, room_id, user_id)
         time_now = self._clock.time_msec()
         return {"event": pdu.get_pdu_json(time_now), "room_version": room_version}
 
-    @defer.inlineCallbacks
-    def on_invite_request(self, origin, content, room_version):
+    async def on_invite_request(self, origin, content, room_version):
         if room_version not in KNOWN_ROOM_VERSIONS:
             raise SynapseError(
                 400,
@@ -369,28 +354,27 @@ class FederationServer(FederationBase):
 
         pdu = event_from_pdu_json(content, format_ver)
         origin_host, _ = parse_server_name(origin)
-        yield self.check_server_matches_acl(origin_host, pdu.room_id)
-        pdu = yield self._check_sigs_and_hash(room_version, pdu)
-        ret_pdu = yield self.handler.on_invite_request(origin, pdu)
+        await self.check_server_matches_acl(origin_host, pdu.room_id)
+        pdu = await self._check_sigs_and_hash(room_version, pdu)
+        ret_pdu = await self.handler.on_invite_request(origin, pdu)
         time_now = self._clock.time_msec()
         return {"event": ret_pdu.get_pdu_json(time_now)}
 
-    @defer.inlineCallbacks
-    def on_send_join_request(self, origin, content, room_id):
+    async def on_send_join_request(self, origin, content, room_id):
         logger.debug("on_send_join_request: content: %s", content)
 
-        room_version = yield self.store.get_room_version(room_id)
+        room_version = await self.store.get_room_version(room_id)
         format_ver = room_version_to_event_format(room_version)
         pdu = event_from_pdu_json(content, format_ver)
 
         origin_host, _ = parse_server_name(origin)
-        yield self.check_server_matches_acl(origin_host, pdu.room_id)
+        await self.check_server_matches_acl(origin_host, pdu.room_id)
 
         logger.debug("on_send_join_request: pdu sigs: %s", pdu.signatures)
 
-        pdu = yield self._check_sigs_and_hash(room_version, pdu)
+        pdu = await self._check_sigs_and_hash(room_version, pdu)
 
-        res_pdus = yield self.handler.on_send_join_request(origin, pdu)
+        res_pdus = await self.handler.on_send_join_request(origin, pdu)
         time_now = self._clock.time_msec()
         return (
             200,
@@ -402,48 +386,44 @@ class FederationServer(FederationBase):
             },
         )
 
-    @defer.inlineCallbacks
-    def on_make_leave_request(self, origin, room_id, user_id):
+    async def on_make_leave_request(self, origin, room_id, user_id):
         origin_host, _ = parse_server_name(origin)
-        yield self.check_server_matches_acl(origin_host, room_id)
-        pdu = yield self.handler.on_make_leave_request(origin, room_id, user_id)
+        await self.check_server_matches_acl(origin_host, room_id)
+        pdu = await self.handler.on_make_leave_request(origin, room_id, user_id)
 
-        room_version = yield self.store.get_room_version(room_id)
+        room_version = await self.store.get_room_version(room_id)
 
         time_now = self._clock.time_msec()
         return {"event": pdu.get_pdu_json(time_now), "room_version": room_version}
 
-    @defer.inlineCallbacks
-    def on_send_leave_request(self, origin, content, room_id):
+    async def on_send_leave_request(self, origin, content, room_id):
         logger.debug("on_send_leave_request: content: %s", content)
 
-        room_version = yield self.store.get_room_version(room_id)
+        room_version = await self.store.get_room_version(room_id)
         format_ver = room_version_to_event_format(room_version)
         pdu = event_from_pdu_json(content, format_ver)
 
         origin_host, _ = parse_server_name(origin)
-        yield self.check_server_matches_acl(origin_host, pdu.room_id)
+        await self.check_server_matches_acl(origin_host, pdu.room_id)
 
         logger.debug("on_send_leave_request: pdu sigs: %s", pdu.signatures)
 
-        pdu = yield self._check_sigs_and_hash(room_version, pdu)
+        pdu = await self._check_sigs_and_hash(room_version, pdu)
 
-        yield self.handler.on_send_leave_request(origin, pdu)
+        await self.handler.on_send_leave_request(origin, pdu)
         return 200, {}
 
-    @defer.inlineCallbacks
-    def on_event_auth(self, origin, room_id, event_id):
-        with (yield self._server_linearizer.queue((origin, room_id))):
+    async def on_event_auth(self, origin, room_id, event_id):
+        with (await self._server_linearizer.queue((origin, room_id))):
             origin_host, _ = parse_server_name(origin)
-            yield self.check_server_matches_acl(origin_host, room_id)
+            await self.check_server_matches_acl(origin_host, room_id)
 
             time_now = self._clock.time_msec()
-            auth_pdus = yield self.handler.on_event_auth(event_id)
+            auth_pdus = await self.handler.on_event_auth(event_id)
             res = {"auth_chain": [a.get_pdu_json(time_now) for a in auth_pdus]}
         return 200, res
 
-    @defer.inlineCallbacks
-    def on_query_auth_request(self, origin, content, room_id, event_id):
+    async def on_query_auth_request(self, origin, content, room_id, event_id):
         """
         Content is a dict with keys::
             auth_chain (list): A list of events that give the auth chain.
@@ -462,22 +442,22 @@ class FederationServer(FederationBase):
         Returns:
             Deferred: Results in `dict` with the same format as `content`
         """
-        with (yield self._server_linearizer.queue((origin, room_id))):
+        with (await self._server_linearizer.queue((origin, room_id))):
             origin_host, _ = parse_server_name(origin)
-            yield self.check_server_matches_acl(origin_host, room_id)
+            await self.check_server_matches_acl(origin_host, room_id)
 
-            room_version = yield self.store.get_room_version(room_id)
+            room_version = await self.store.get_room_version(room_id)
             format_ver = room_version_to_event_format(room_version)
 
             auth_chain = [
                 event_from_pdu_json(e, format_ver) for e in content["auth_chain"]
             ]
 
-            signed_auth = yield self._check_sigs_and_hash_and_fetch(
+            signed_auth = await self._check_sigs_and_hash_and_fetch(
                 origin, auth_chain, outlier=True, room_version=room_version
             )
 
-            ret = yield self.handler.on_query_auth(
+            ret = await self.handler.on_query_auth(
                 origin,
                 event_id,
                 room_id,
@@ -503,16 +483,14 @@ class FederationServer(FederationBase):
         return self.on_query_request("user_devices", user_id)
 
     @trace
-    @defer.inlineCallbacks
-    @log_function
-    def on_claim_client_keys(self, origin, content):
+    async def on_claim_client_keys(self, origin, content):
         query = []
         for user_id, device_keys in content.get("one_time_keys", {}).items():
             for device_id, algorithm in device_keys.items():
                 query.append((user_id, device_id, algorithm))
 
         log_kv({"message": "Claiming one time keys.", "user, device pairs": query})
-        results = yield self.store.claim_e2e_one_time_keys(query)
+        results = await self.store.claim_e2e_one_time_keys(query)
 
         json_result = {}
         for user_id, device_keys in results.items():
@@ -536,14 +514,12 @@ class FederationServer(FederationBase):
 
         return {"one_time_keys": json_result}
 
-    @defer.inlineCallbacks
-    @log_function
-    def on_get_missing_events(
+    async def on_get_missing_events(
         self, origin, room_id, earliest_events, latest_events, limit
     ):
-        with (yield self._server_linearizer.queue((origin, room_id))):
+        with (await self._server_linearizer.queue((origin, room_id))):
             origin_host, _ = parse_server_name(origin)
-            yield self.check_server_matches_acl(origin_host, room_id)
+            await self.check_server_matches_acl(origin_host, room_id)
 
             logger.info(
                 "on_get_missing_events: earliest_events: %r, latest_events: %r,"
@@ -553,7 +529,7 @@ class FederationServer(FederationBase):
                 limit,
             )
 
-            missing_events = yield self.handler.on_get_missing_events(
+            missing_events = await self.handler.on_get_missing_events(
                 origin, room_id, earliest_events, latest_events, limit
             )
 
@@ -586,8 +562,7 @@ class FederationServer(FederationBase):
             destination=None,
         )
 
-    @defer.inlineCallbacks
-    def _handle_received_pdu(self, origin, pdu):
+    async def _handle_received_pdu(self, origin, pdu):
         """ Process a PDU received in a federation /send/ transaction.
 
         If the event is invalid, then this method throws a FederationError.
@@ -640,37 +615,34 @@ class FederationServer(FederationBase):
                 logger.info("Accepting join PDU %s from %s", pdu.event_id, origin)
 
         # We've already checked that we know the room version by this point
-        room_version = yield self.store.get_room_version(pdu.room_id)
+        room_version = await self.store.get_room_version(pdu.room_id)
 
         # Check signature.
         try:
-            pdu = yield self._check_sigs_and_hash(room_version, pdu)
+            pdu = await self._check_sigs_and_hash(room_version, pdu)
         except SynapseError as e:
             raise FederationError("ERROR", e.code, e.msg, affected=pdu.event_id)
 
-        yield self.handler.on_receive_pdu(origin, pdu, sent_to_us_directly=True)
+        await self.handler.on_receive_pdu(origin, pdu, sent_to_us_directly=True)
 
     def __str__(self):
         return "<ReplicationLayer(%s)>" % self.server_name
 
-    @defer.inlineCallbacks
-    def exchange_third_party_invite(
+    async def exchange_third_party_invite(
         self, sender_user_id, target_user_id, room_id, signed
     ):
-        ret = yield self.handler.exchange_third_party_invite(
+        ret = await self.handler.exchange_third_party_invite(
             sender_user_id, target_user_id, room_id, signed
         )
         return ret
 
-    @defer.inlineCallbacks
-    def on_exchange_third_party_invite_request(self, room_id, event_dict):
-        ret = yield self.handler.on_exchange_third_party_invite_request(
+    async def on_exchange_third_party_invite_request(self, room_id, event_dict):
+        ret = await self.handler.on_exchange_third_party_invite_request(
             room_id, event_dict
         )
         return ret
 
-    @defer.inlineCallbacks
-    def check_server_matches_acl(self, server_name, room_id):
+    async def check_server_matches_acl(self, server_name, room_id):
         """Check if the given server is allowed by the server ACLs in the room
 
         Args:
@@ -680,13 +652,13 @@ class FederationServer(FederationBase):
         Raises:
             AuthError if the server does not match the ACL
         """
-        state_ids = yield self.store.get_current_state_ids(room_id)
+        state_ids = await self.store.get_current_state_ids(room_id)
         acl_event_id = state_ids.get((EventTypes.ServerACL, ""))
 
         if not acl_event_id:
             return
 
-        acl_event = yield self.store.get_event(acl_event_id)
+        acl_event = await self.store.get_event(acl_event_id)
         if server_matches_acl_event(server_name, acl_event):
             return
 
@@ -709,7 +681,7 @@ def server_matches_acl_event(server_name, acl_event):
     # server name is a literal IP
     allow_ip_literals = acl_event.content.get("allow_ip_literals", True)
     if not isinstance(allow_ip_literals, bool):
-        logger.warn("Ignorning non-bool allow_ip_literals flag")
+        logger.warning("Ignorning non-bool allow_ip_literals flag")
         allow_ip_literals = True
     if not allow_ip_literals:
         # check for ipv6 literals. These start with '['.
@@ -723,7 +695,7 @@ def server_matches_acl_event(server_name, acl_event):
     # next,  check the deny list
     deny = acl_event.content.get("deny", [])
     if not isinstance(deny, (list, tuple)):
-        logger.warn("Ignorning non-list deny ACL %s", deny)
+        logger.warning("Ignorning non-list deny ACL %s", deny)
         deny = []
     for e in deny:
         if _acl_entry_matches(server_name, e):
@@ -733,7 +705,7 @@ def server_matches_acl_event(server_name, acl_event):
     # then the allow list.
     allow = acl_event.content.get("allow", [])
     if not isinstance(allow, (list, tuple)):
-        logger.warn("Ignorning non-list allow ACL %s", allow)
+        logger.warning("Ignorning non-list allow ACL %s", allow)
         allow = []
     for e in allow:
         if _acl_entry_matches(server_name, e):
@@ -747,7 +719,7 @@ def server_matches_acl_event(server_name, acl_event):
 
 def _acl_entry_matches(server_name, acl_entry):
     if not isinstance(acl_entry, six.string_types):
-        logger.warn(
+        logger.warning(
             "Ignoring non-str ACL entry '%s' (is %s)", acl_entry, type(acl_entry)
         )
         return False
@@ -799,15 +771,14 @@ class FederationHandlerRegistry(object):
 
         self.query_handlers[query_type] = handler
 
-    @defer.inlineCallbacks
-    def on_edu(self, edu_type, origin, content):
+    async def on_edu(self, edu_type, origin, content):
         handler = self.edu_handlers.get(edu_type)
         if not handler:
-            logger.warn("No handler registered for EDU type %s", edu_type)
+            logger.warning("No handler registered for EDU type %s", edu_type)
 
         with start_active_span_from_edu(content, "handle_edu"):
             try:
-                yield handler(origin, content)
+                await handler(origin, content)
             except SynapseError as e:
                 logger.info("Failed to handle edu %r: %r", edu_type, e)
             except Exception:
@@ -816,7 +787,7 @@ class FederationHandlerRegistry(object):
     def on_query(self, query_type, args):
         handler = self.query_handlers.get(query_type)
         if not handler:
-            logger.warn("No handler registered for query type %s", query_type)
+            logger.warning("No handler registered for query type %s", query_type)
             raise NotFoundError("No handler for Query type '%s'" % (query_type,))
 
         return handler(args)
@@ -840,7 +811,7 @@ class ReplicationFederationHandlerRegistry(FederationHandlerRegistry):
 
         super(ReplicationFederationHandlerRegistry, self).__init__()
 
-    def on_edu(self, edu_type, origin, content):
+    async def on_edu(self, edu_type, origin, content):
         """Overrides FederationHandlerRegistry
         """
         if not self.config.use_presence and edu_type == "m.presence":
@@ -848,17 +819,17 @@ class ReplicationFederationHandlerRegistry(FederationHandlerRegistry):
 
         handler = self.edu_handlers.get(edu_type)
         if handler:
-            return super(ReplicationFederationHandlerRegistry, self).on_edu(
+            return await super(ReplicationFederationHandlerRegistry, self).on_edu(
                 edu_type, origin, content
             )
 
-        return self._send_edu(edu_type=edu_type, origin=origin, content=content)
+        return await self._send_edu(edu_type=edu_type, origin=origin, content=content)
 
-    def on_query(self, query_type, args):
+    async def on_query(self, query_type, args):
         """Overrides FederationHandlerRegistry
         """
         handler = self.query_handlers.get(query_type)
         if handler:
-            return handler(args)
+            return await handler(args)
 
-        return self._get_query_client(query_type=query_type, args=args)
+        return await self._get_query_client(query_type=query_type, args=args)
diff --git a/synapse/federation/send_queue.py b/synapse/federation/send_queue.py
index 454456a52d..ced4925a98 100644
--- a/synapse/federation/send_queue.py
+++ b/synapse/federation/send_queue.py
@@ -36,6 +36,8 @@ from six import iteritems
 
 from sortedcontainers import SortedDict
 
+from twisted.internet import defer
+
 from synapse.metrics import LaterGauge
 from synapse.storage.presence import UserPresenceState
 from synapse.util.metrics import Measure
@@ -212,7 +214,7 @@ class FederationRemoteSendQueue(object):
             receipt (synapse.types.ReadReceipt):
         """
         # nothing to do here: the replication listener will handle it.
-        pass
+        return defer.succeed(None)
 
     def send_presence(self, states):
         """As per FederationSender
diff --git a/synapse/federation/sender/per_destination_queue.py b/synapse/federation/sender/per_destination_queue.py
index cc75c39476..a5b36b1827 100644
--- a/synapse/federation/sender/per_destination_queue.py
+++ b/synapse/federation/sender/per_destination_queue.py
@@ -192,15 +192,16 @@ class PerDestinationQueue(object):
                 # We have to keep 2 free slots for presence and rr_edus
                 limit = MAX_EDUS_PER_TRANSACTION - 2
 
-                device_update_edus, dev_list_id = (
-                    yield self._get_device_update_edus(limit)
+                device_update_edus, dev_list_id = yield self._get_device_update_edus(
+                    limit
                 )
 
                 limit -= len(device_update_edus)
 
-                to_device_edus, device_stream_id = (
-                    yield self._get_to_device_message_edus(limit)
-                )
+                (
+                    to_device_edus,
+                    device_stream_id,
+                ) = yield self._get_to_device_message_edus(limit)
 
                 pending_edus = device_update_edus + to_device_edus
 
@@ -359,20 +360,20 @@ class PerDestinationQueue(object):
         last_device_list = self._last_device_list_stream_id
 
         # Retrieve list of new device updates to send to the destination
-        now_stream_id, results = yield self._store.get_devices_by_remote(
+        now_stream_id, results = yield self._store.get_device_updates_by_remote(
             self._destination, last_device_list, limit=limit
         )
         edus = [
             Edu(
                 origin=self._server_name,
                 destination=self._destination,
-                edu_type="m.device_list_update",
+                edu_type=edu_type,
                 content=content,
             )
-            for content in results
+            for (edu_type, content) in results
         ]
 
-        assert len(edus) <= limit, "get_devices_by_remote returned too many EDUs"
+        assert len(edus) <= limit, "get_device_updates_by_remote returned too many EDUs"
 
         return (edus, now_stream_id)
 
diff --git a/synapse/federation/sender/transaction_manager.py b/synapse/federation/sender/transaction_manager.py
index 5b6c79c51a..67b3e1ab6e 100644
--- a/synapse/federation/sender/transaction_manager.py
+++ b/synapse/federation/sender/transaction_manager.py
@@ -146,7 +146,7 @@ class TransactionManager(object):
             if code == 200:
                 for e_id, r in response.get("pdus", {}).items():
                     if "error" in r:
-                        logger.warn(
+                        logger.warning(
                             "TX [%s] {%s} Remote returned error for %s: %s",
                             destination,
                             txn_id,
@@ -155,7 +155,7 @@ class TransactionManager(object):
                         )
             else:
                 for p in pdus:
-                    logger.warn(
+                    logger.warning(
                         "TX [%s] {%s} Failed to send event %s",
                         destination,
                         txn_id,
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index 7b18408144..920fa86853 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -122,10 +122,10 @@ class TransportLayerClient(object):
             Deferred: Results in a dict received from the remote homeserver.
         """
         logger.debug(
-            "backfill dest=%s, room_id=%s, event_tuples=%s, limit=%s",
+            "backfill dest=%s, room_id=%s, event_tuples=%r, limit=%s",
             destination,
             room_id,
-            repr(event_tuples),
+            event_tuples,
             str(limit),
         )
 
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 0f16f21c2d..d6c23f22bd 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -202,7 +202,7 @@ def _parse_auth_header(header_bytes):
         sig = strip_quotes(param_dict["sig"])
         return origin, key, sig
     except Exception as e:
-        logger.warn(
+        logger.warning(
             "Error parsing auth header '%s': %s",
             header_bytes.decode("ascii", "replace"),
             e,
@@ -287,10 +287,12 @@ class BaseFederationServlet(object):
             except NoAuthenticationError:
                 origin = None
                 if self.REQUIRE_AUTH:
-                    logger.warn("authenticate_request failed: missing authentication")
+                    logger.warning(
+                        "authenticate_request failed: missing authentication"
+                    )
                     raise
             except Exception as e:
-                logger.warn("authenticate_request failed: %s", e)
+                logger.warning("authenticate_request failed: %s", e)
                 raise
 
             request_tags = {
diff --git a/synapse/groups/attestations.py b/synapse/groups/attestations.py
index dfd7ae041b..d950a8b246 100644
--- a/synapse/groups/attestations.py
+++ b/synapse/groups/attestations.py
@@ -181,7 +181,7 @@ class GroupAttestionRenewer(object):
                 elif not self.is_mine_id(user_id):
                     destination = get_domain_from_id(user_id)
                 else:
-                    logger.warn(
+                    logger.warning(
                         "Incorrectly trying to do attestations for user: %r in %r",
                         user_id,
                         group_id,
diff --git a/synapse/groups/groups_server.py b/synapse/groups/groups_server.py
index 8f10b6adbb..29e8ffc295 100644
--- a/synapse/groups/groups_server.py
+++ b/synapse/groups/groups_server.py
@@ -488,7 +488,7 @@ class GroupsServerHandler(object):
                 profile = yield self.profile_handler.get_profile_from_cache(user_id)
                 user_profile.update(profile)
             except Exception as e:
-                logger.warn("Error getting profile for %s: %s", user_id, e)
+                logger.warning("Error getting profile for %s: %s", user_id, e)
             user_profiles.append(user_profile)
 
         return {"chunk": user_profiles, "total_user_count_estimate": len(invited_users)}
diff --git a/synapse/handlers/account_data.py b/synapse/handlers/account_data.py
index 38bc67191c..2d7e6df6e4 100644
--- a/synapse/handlers/account_data.py
+++ b/synapse/handlers/account_data.py
@@ -38,9 +38,10 @@ class AccountDataEventSource(object):
                 {"type": "m.tag", "content": {"tags": room_tags}, "room_id": room_id}
             )
 
-        account_data, room_account_data = (
-            yield self.store.get_updated_account_data_for_user(user_id, last_stream_id)
-        )
+        (
+            account_data,
+            room_account_data,
+        ) = yield self.store.get_updated_account_data_for_user(user_id, last_stream_id)
 
         for account_data_type, content in account_data.items():
             results.append({"type": account_data_type, "content": content})
diff --git a/synapse/handlers/admin.py b/synapse/handlers/admin.py
index 1a87b58838..6407d56f8e 100644
--- a/synapse/handlers/admin.py
+++ b/synapse/handlers/admin.py
@@ -30,6 +30,9 @@ class AdminHandler(BaseHandler):
     def __init__(self, hs):
         super(AdminHandler, self).__init__(hs)
 
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
+
     @defer.inlineCallbacks
     def get_whois(self, user):
         connections = []
@@ -205,7 +208,7 @@ class AdminHandler(BaseHandler):
 
                 from_key = events[-1].internal_metadata.after
 
-                events = yield filter_events_for_client(self.store, user_id, events)
+                events = yield filter_events_for_client(self.storage, user_id, events)
 
                 writer.write_events(room_id, events)
 
@@ -241,7 +244,7 @@ class AdminHandler(BaseHandler):
             for event_id in extremities:
                 if not event_to_unseen_prevs[event_id]:
                     continue
-                state = yield self.store.get_state_for_event(event_id)
+                state = yield self.state_store.get_state_for_event(event_id)
                 writer.write_state(room_id, event_id, state)
 
         return writer.finished()
diff --git a/synapse/handlers/appservice.py b/synapse/handlers/appservice.py
index 3e9b298154..fe62f78e67 100644
--- a/synapse/handlers/appservice.py
+++ b/synapse/handlers/appservice.py
@@ -73,7 +73,10 @@ class ApplicationServicesHandler(object):
             try:
                 limit = 100
                 while True:
-                    upper_bound, events = yield self.store.get_new_events_for_appservice(
+                    (
+                        upper_bound,
+                        events,
+                    ) = yield self.store.get_new_events_for_appservice(
                         self.current_max, limit
                     )
 
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 333eb30625..7a0f54ca24 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -525,7 +525,7 @@ class AuthHandler(BaseHandler):
 
         result = None
         if not user_infos:
-            logger.warn("Attempted to login as %s but they do not exist", user_id)
+            logger.warning("Attempted to login as %s but they do not exist", user_id)
         elif len(user_infos) == 1:
             # a single match (possibly not exact)
             result = user_infos.popitem()
@@ -534,7 +534,7 @@ class AuthHandler(BaseHandler):
             result = (user_id, user_infos[user_id])
         else:
             # multiple matches, none of them exact
-            logger.warn(
+            logger.warning(
                 "Attempted to login as %s but it matches more than one user "
                 "inexactly: %r",
                 user_id,
@@ -728,7 +728,7 @@ class AuthHandler(BaseHandler):
 
         result = yield self.validate_hash(password, password_hash)
         if not result:
-            logger.warn("Failed password login for user %s", user_id)
+            logger.warning("Failed password login for user %s", user_id)
             return None
         return user_id
 
diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py
index 5f23ee4488..26ef5e150c 100644
--- a/synapse/handlers/device.py
+++ b/synapse/handlers/device.py
@@ -46,6 +46,7 @@ class DeviceWorkerHandler(BaseHandler):
 
         self.hs = hs
         self.state = hs.get_state_handler()
+        self.state_store = hs.get_storage().state
         self._auth_handler = hs.get_auth_handler()
 
     @trace
@@ -178,7 +179,7 @@ class DeviceWorkerHandler(BaseHandler):
                 continue
 
             # mapping from event_id -> state_dict
-            prev_state_ids = yield self.store.get_state_ids_for_events(event_ids)
+            prev_state_ids = yield self.state_store.get_state_ids_for_events(event_ids)
 
             # Check if we've joined the room? If so we just blindly add all the users to
             # the "possibly changed" users.
@@ -458,7 +459,18 @@ class DeviceHandler(DeviceWorkerHandler):
     @defer.inlineCallbacks
     def on_federation_query_user_devices(self, user_id):
         stream_id, devices = yield self.store.get_devices_with_keys_by_user(user_id)
-        return {"user_id": user_id, "stream_id": stream_id, "devices": devices}
+        master_key = yield self.store.get_e2e_cross_signing_key(user_id, "master")
+        self_signing_key = yield self.store.get_e2e_cross_signing_key(
+            user_id, "self_signing"
+        )
+
+        return {
+            "user_id": user_id,
+            "stream_id": stream_id,
+            "devices": devices,
+            "master_key": master_key,
+            "self_signing_key": self_signing_key,
+        }
 
     @defer.inlineCallbacks
     def user_left_room(self, user, room_id):
@@ -656,7 +668,7 @@ class DeviceListUpdater(object):
         except (NotRetryingDestination, RequestSendFailed, HttpResponseException):
             # TODO: Remember that we are now out of sync and try again
             # later
-            logger.warn("Failed to handle device list update for %s", user_id)
+            logger.warning("Failed to handle device list update for %s", user_id)
             # We abort on exceptions rather than accepting the update
             # as otherwise synapse will 'forget' that its device list
             # is out of date. If we bail then we will retry the resync
@@ -694,7 +706,7 @@ class DeviceListUpdater(object):
         # up on storing the total list of devices and only handle the
         # delta instead.
         if len(devices) > 1000:
-            logger.warn(
+            logger.warning(
                 "Ignoring device list snapshot for %s as it has >1K devs (%d)",
                 user_id,
                 len(devices),
diff --git a/synapse/handlers/devicemessage.py b/synapse/handlers/devicemessage.py
index 0043cbea17..73b9e120f5 100644
--- a/synapse/handlers/devicemessage.py
+++ b/synapse/handlers/devicemessage.py
@@ -52,7 +52,7 @@ class DeviceMessageHandler(object):
         local_messages = {}
         sender_user_id = content["sender"]
         if origin != get_domain_from_id(sender_user_id):
-            logger.warn(
+            logger.warning(
                 "Dropping device message from %r with spoofed sender %r",
                 origin,
                 sender_user_id,
diff --git a/synapse/handlers/directory.py b/synapse/handlers/directory.py
index 526379c6f7..c4632f8984 100644
--- a/synapse/handlers/directory.py
+++ b/synapse/handlers/directory.py
@@ -250,7 +250,7 @@ class DirectoryHandler(BaseHandler):
                     ignore_backoff=True,
                 )
             except CodeMessageException as e:
-                logging.warn("Error retrieving alias")
+                logging.warning("Error retrieving alias")
                 if e.code == 404:
                     result = None
                 else:
diff --git a/synapse/handlers/e2e_keys.py b/synapse/handlers/e2e_keys.py
index 5ea54f60be..f09a0b73c8 100644
--- a/synapse/handlers/e2e_keys.py
+++ b/synapse/handlers/e2e_keys.py
@@ -36,6 +36,8 @@ from synapse.types import (
     get_verify_key_from_cross_signing_key,
 )
 from synapse.util import unwrapFirstError
+from synapse.util.async_helpers import Linearizer
+from synapse.util.caches.expiringcache import ExpiringCache
 from synapse.util.retryutils import NotRetryingDestination
 
 logger = logging.getLogger(__name__)
@@ -49,10 +51,19 @@ class E2eKeysHandler(object):
         self.is_mine = hs.is_mine
         self.clock = hs.get_clock()
 
+        self._edu_updater = SigningKeyEduUpdater(hs, self)
+
+        federation_registry = hs.get_federation_registry()
+
+        # FIXME: switch to m.signing_key_update when MSC1756 is merged into the spec
+        federation_registry.register_edu_handler(
+            "org.matrix.signing_key_update",
+            self._edu_updater.incoming_signing_key_update,
+        )
         # doesn't really work as part of the generic query API, because the
         # query request requires an object POST, but we abuse the
         # "query handler" interface.
-        hs.get_federation_registry().register_query_handler(
+        federation_registry.register_query_handler(
             "client_keys", self.on_federation_query_client_keys
         )
 
@@ -119,9 +130,10 @@ class E2eKeysHandler(object):
                 else:
                     query_list.append((user_id, None))
 
-            user_ids_not_in_cache, remote_results = (
-                yield self.store.get_user_devices_from_cache(query_list)
-            )
+            (
+                user_ids_not_in_cache,
+                remote_results,
+            ) = yield self.store.get_user_devices_from_cache(query_list)
             for user_id, devices in iteritems(remote_results):
                 user_devices = results.setdefault(user_id, {})
                 for device_id, device in iteritems(devices):
@@ -207,13 +219,15 @@ class E2eKeysHandler(object):
                     if user_id in destination_query:
                         results[user_id] = keys
 
-                for user_id, key in remote_result["master_keys"].items():
-                    if user_id in destination_query:
-                        cross_signing_keys["master_keys"][user_id] = key
+                if "master_keys" in remote_result:
+                    for user_id, key in remote_result["master_keys"].items():
+                        if user_id in destination_query:
+                            cross_signing_keys["master_keys"][user_id] = key
 
-                for user_id, key in remote_result["self_signing_keys"].items():
-                    if user_id in destination_query:
-                        cross_signing_keys["self_signing_keys"][user_id] = key
+                if "self_signing_keys" in remote_result:
+                    for user_id, key in remote_result["self_signing_keys"].items():
+                        if user_id in destination_query:
+                            cross_signing_keys["self_signing_keys"][user_id] = key
 
             except Exception as e:
                 failure = _exception_to_failure(e)
@@ -251,7 +265,7 @@ class E2eKeysHandler(object):
 
         Returns:
             defer.Deferred[dict[str, dict[str, dict]]]: map from
-                (master|self_signing|user_signing) -> user_id -> key
+                (master_keys|self_signing_keys|user_signing_keys) -> user_id -> key
         """
         master_keys = {}
         self_signing_keys = {}
@@ -343,7 +357,16 @@ class E2eKeysHandler(object):
         """
         device_keys_query = query_body.get("device_keys", {})
         res = yield self.query_local_devices(device_keys_query)
-        return {"device_keys": res}
+        ret = {"device_keys": res}
+
+        # add in the cross-signing keys
+        cross_signing_keys = yield self.get_cross_signing_keys_from_cache(
+            device_keys_query, None
+        )
+
+        ret.update(cross_signing_keys)
+
+        return ret
 
     @trace
     @defer.inlineCallbacks
@@ -688,17 +711,21 @@ class E2eKeysHandler(object):
 
         try:
             # get our self-signing key to verify the signatures
-            _, self_signing_key_id, self_signing_verify_key = yield self._get_e2e_cross_signing_verify_key(
-                user_id, "self_signing"
-            )
+            (
+                _,
+                self_signing_key_id,
+                self_signing_verify_key,
+            ) = yield self._get_e2e_cross_signing_verify_key(user_id, "self_signing")
 
             # get our master key, since we may have received a signature of it.
             # We need to fetch it here so that we know what its key ID is, so
             # that we can check if a signature that was sent is a signature of
             # the master key or of a device
-            master_key, _, master_verify_key = yield self._get_e2e_cross_signing_verify_key(
-                user_id, "master"
-            )
+            (
+                master_key,
+                _,
+                master_verify_key,
+            ) = yield self._get_e2e_cross_signing_verify_key(user_id, "master")
 
             # fetch our stored devices.  This is used to 1. verify
             # signatures on the master key, and 2. to compare with what
@@ -838,9 +865,11 @@ class E2eKeysHandler(object):
 
         try:
             # get our user-signing key to verify the signatures
-            user_signing_key, user_signing_key_id, user_signing_verify_key = yield self._get_e2e_cross_signing_verify_key(
-                user_id, "user_signing"
-            )
+            (
+                user_signing_key,
+                user_signing_key_id,
+                user_signing_verify_key,
+            ) = yield self._get_e2e_cross_signing_verify_key(user_id, "user_signing")
         except SynapseError as e:
             failure = _exception_to_failure(e)
             for user, devicemap in signatures.items():
@@ -859,7 +888,11 @@ class E2eKeysHandler(object):
             try:
                 # get the target user's master key, to make sure it matches
                 # what was sent
-                master_key, master_key_id, _ = yield self._get_e2e_cross_signing_verify_key(
+                (
+                    master_key,
+                    master_key_id,
+                    _,
+                ) = yield self._get_e2e_cross_signing_verify_key(
                     target_user, "master", user_id
                 )
 
@@ -1047,3 +1080,100 @@ class SignatureListItem:
     target_user_id = attr.ib()
     target_device_id = attr.ib()
     signature = attr.ib()
+
+
+class SigningKeyEduUpdater(object):
+    """Handles incoming signing key updates from federation and updates the DB"""
+
+    def __init__(self, hs, e2e_keys_handler):
+        self.store = hs.get_datastore()
+        self.federation = hs.get_federation_client()
+        self.clock = hs.get_clock()
+        self.e2e_keys_handler = e2e_keys_handler
+
+        self._remote_edu_linearizer = Linearizer(name="remote_signing_key")
+
+        # user_id -> list of updates waiting to be handled.
+        self._pending_updates = {}
+
+        # Recently seen stream ids. We don't bother keeping these in the DB,
+        # but they're useful to have them about to reduce the number of spurious
+        # resyncs.
+        self._seen_updates = ExpiringCache(
+            cache_name="signing_key_update_edu",
+            clock=self.clock,
+            max_len=10000,
+            expiry_ms=30 * 60 * 1000,
+            iterable=True,
+        )
+
+    @defer.inlineCallbacks
+    def incoming_signing_key_update(self, origin, edu_content):
+        """Called on incoming signing key update from federation. Responsible for
+        parsing the EDU and adding to pending updates list.
+
+        Args:
+            origin (string): the server that sent the EDU
+            edu_content (dict): the contents of the EDU
+        """
+
+        user_id = edu_content.pop("user_id")
+        master_key = edu_content.pop("master_key", None)
+        self_signing_key = edu_content.pop("self_signing_key", None)
+
+        if get_domain_from_id(user_id) != origin:
+            logger.warning("Got signing key update edu for %r from %r", user_id, origin)
+            return
+
+        room_ids = yield self.store.get_rooms_for_user(user_id)
+        if not room_ids:
+            # We don't share any rooms with this user. Ignore update, as we
+            # probably won't get any further updates.
+            return
+
+        self._pending_updates.setdefault(user_id, []).append(
+            (master_key, self_signing_key)
+        )
+
+        yield self._handle_signing_key_updates(user_id)
+
+    @defer.inlineCallbacks
+    def _handle_signing_key_updates(self, user_id):
+        """Actually handle pending updates.
+
+        Args:
+            user_id (string): the user whose updates we are processing
+        """
+
+        device_handler = self.e2e_keys_handler.device_handler
+
+        with (yield self._remote_edu_linearizer.queue(user_id)):
+            pending_updates = self._pending_updates.pop(user_id, [])
+            if not pending_updates:
+                # This can happen since we batch updates
+                return
+
+            device_ids = []
+
+            logger.info("pending updates: %r", pending_updates)
+
+            for master_key, self_signing_key in pending_updates:
+                if master_key:
+                    yield self.store.set_e2e_cross_signing_key(
+                        user_id, "master", master_key
+                    )
+                    _, verify_key = get_verify_key_from_cross_signing_key(master_key)
+                    # verify_key is a VerifyKey from signedjson, which uses
+                    # .version to denote the portion of the key ID after the
+                    # algorithm and colon, which is the device ID
+                    device_ids.append(verify_key.version)
+                if self_signing_key:
+                    yield self.store.set_e2e_cross_signing_key(
+                        user_id, "self_signing", self_signing_key
+                    )
+                    _, verify_key = get_verify_key_from_cross_signing_key(
+                        self_signing_key
+                    )
+                    device_ids.append(verify_key.version)
+
+            yield device_handler.notify_device_update(user_id, device_ids)
diff --git a/synapse/handlers/events.py b/synapse/handlers/events.py
index 5e748687e3..45fe13c62f 100644
--- a/synapse/handlers/events.py
+++ b/synapse/handlers/events.py
@@ -147,6 +147,10 @@ class EventStreamHandler(BaseHandler):
 
 
 class EventHandler(BaseHandler):
+    def __init__(self, hs):
+        super(EventHandler, self).__init__(hs)
+        self.storage = hs.get_storage()
+
     @defer.inlineCallbacks
     def get_event(self, user, room_id, event_id):
         """Retrieve a single specified event.
@@ -172,7 +176,7 @@ class EventHandler(BaseHandler):
         is_peeking = user.to_string() not in users
 
         filtered = yield filter_events_for_client(
-            self.store, user.to_string(), [event], is_peeking=is_peeking
+            self.storage, user.to_string(), [event], is_peeking=is_peeking
         )
 
         if not filtered:
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 488058fe68..8cafcfdab0 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -45,6 +45,7 @@ from synapse.api.errors import (
 from synapse.api.room_versions import KNOWN_ROOM_VERSIONS, RoomVersions
 from synapse.crypto.event_signing import compute_event_signature
 from synapse.event_auth import auth_types_for_event
+from synapse.events.snapshot import EventContext
 from synapse.events.validator import EventValidator
 from synapse.logging.context import (
     make_deferred_yieldable,
@@ -109,6 +110,8 @@ class FederationHandler(BaseHandler):
         self.hs = hs
 
         self.store = hs.get_datastore()
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
         self.federation_client = hs.get_federation_client()
         self.state_handler = hs.get_state_handler()
         self.server_name = hs.hostname
@@ -180,7 +183,7 @@ class FederationHandler(BaseHandler):
         try:
             self._sanity_check_event(pdu)
         except SynapseError as err:
-            logger.warn(
+            logger.warning(
                 "[%s %s] Received event failed sanity checks", room_id, event_id
             )
             raise FederationError("ERROR", err.code, err.msg, affected=pdu.event_id)
@@ -301,7 +304,7 @@ class FederationHandler(BaseHandler):
                 # following.
 
                 if sent_to_us_directly:
-                    logger.warn(
+                    logger.warning(
                         "[%s %s] Rejecting: failed to fetch %d prev events: %s",
                         room_id,
                         event_id,
@@ -324,7 +327,7 @@ class FederationHandler(BaseHandler):
                 event_map = {event_id: pdu}
                 try:
                     # Get the state of the events we know about
-                    ours = yield self.store.get_state_groups_ids(room_id, seen)
+                    ours = yield self.state_store.get_state_groups_ids(room_id, seen)
 
                     # state_maps is a list of mappings from (type, state_key) to event_id
                     state_maps = list(
@@ -350,10 +353,11 @@ class FederationHandler(BaseHandler):
                             # note that if any of the missing prevs share missing state or
                             # auth events, the requests to fetch those events are deduped
                             # by the get_pdu_cache in federation_client.
-                            remote_state, got_auth_chain = (
-                                yield self.federation_client.get_state_for_room(
-                                    origin, room_id, p
-                                )
+                            (
+                                remote_state,
+                                got_auth_chain,
+                            ) = yield self.federation_client.get_state_for_room(
+                                origin, room_id, p
                             )
 
                             # we want the state *after* p; get_state_for_room returns the
@@ -405,7 +409,7 @@ class FederationHandler(BaseHandler):
                     state = [event_map[e] for e in six.itervalues(state_map)]
                     auth_chain = list(auth_chains)
                 except Exception:
-                    logger.warn(
+                    logger.warning(
                         "[%s %s] Error attempting to resolve state at missing "
                         "prev_events",
                         room_id,
@@ -518,7 +522,9 @@ class FederationHandler(BaseHandler):
             # We failed to get the missing events, but since we need to handle
             # the case of `get_missing_events` not returning the necessary
             # events anyway, it is safe to simply log the error and continue.
-            logger.warn("[%s %s]: Failed to get prev_events: %s", room_id, event_id, e)
+            logger.warning(
+                "[%s %s]: Failed to get prev_events: %s", room_id, event_id, e
+            )
             return
 
         logger.info(
@@ -545,7 +551,7 @@ class FederationHandler(BaseHandler):
                     yield self.on_receive_pdu(origin, ev, sent_to_us_directly=False)
                 except FederationError as e:
                     if e.code == 403:
-                        logger.warn(
+                        logger.warning(
                             "[%s %s] Received prev_event %s failed history check.",
                             room_id,
                             event_id,
@@ -888,7 +894,7 @@ class FederationHandler(BaseHandler):
         # We set `check_history_visibility_only` as we might otherwise get false
         # positives from users having been erased.
         filtered_extremities = yield filter_events_for_server(
-            self.store,
+            self.storage,
             self.server_name,
             list(extremities_events.values()),
             redact=False,
@@ -1059,7 +1065,7 @@ class FederationHandler(BaseHandler):
             SynapseError if the event does not pass muster
         """
         if len(ev.prev_event_ids()) > 20:
-            logger.warn(
+            logger.warning(
                 "Rejecting event %s which has %i prev_events",
                 ev.event_id,
                 len(ev.prev_event_ids()),
@@ -1067,7 +1073,7 @@ class FederationHandler(BaseHandler):
             raise SynapseError(http_client.BAD_REQUEST, "Too many prev_events")
 
         if len(ev.auth_event_ids()) > 10:
-            logger.warn(
+            logger.warning(
                 "Rejecting event %s which has %i auth_events",
                 ev.event_id,
                 len(ev.auth_event_ids()),
@@ -1101,7 +1107,7 @@ class FederationHandler(BaseHandler):
     @defer.inlineCallbacks
     def do_invite_join(self, target_hosts, room_id, joinee, content):
         """ Attempts to join the `joinee` to the room `room_id` via the
-        server `target_host`.
+        servers contained in `target_hosts`.
 
         This first triggers a /make_join/ request that returns a partial
         event that we can fill out and sign. This is then sent to the
@@ -1110,6 +1116,15 @@ class FederationHandler(BaseHandler):
 
         We suspend processing of any received events from this room until we
         have finished processing the join.
+
+        Args:
+            target_hosts (Iterable[str]): List of servers to attempt to join the room with.
+
+            room_id (str): The ID of the room to join.
+
+            joinee (str): The User ID of the joining user.
+
+            content (dict): The event content to use for the join event.
         """
         logger.debug("Joining %s to %s", joinee, room_id)
 
@@ -1169,6 +1184,22 @@ class FederationHandler(BaseHandler):
 
             yield self._persist_auth_tree(origin, auth_chain, state, event)
 
+            # Check whether this room is the result of an upgrade of a room we already know
+            # about. If so, migrate over user information
+            predecessor = yield self.store.get_room_predecessor(room_id)
+            if not predecessor:
+                return
+            old_room_id = predecessor["room_id"]
+            logger.debug(
+                "Found predecessor for %s during remote join: %s", room_id, old_room_id
+            )
+
+            # We retrieve the room member handler here as to not cause a cyclic dependency
+            member_handler = self.hs.get_room_member_handler()
+            yield member_handler.transfer_room_state_on_room_upgrade(
+                old_room_id, room_id
+            )
+
             logger.debug("Finished joining %s to %s", joinee, room_id)
         finally:
             room_queue = self.room_queues[room_id]
@@ -1203,7 +1234,7 @@ class FederationHandler(BaseHandler):
                 with nested_logging_context(p.event_id):
                     yield self.on_receive_pdu(origin, p, sent_to_us_directly=True)
             except Exception as e:
-                logger.warn(
+                logger.warning(
                     "Error handling queued PDU %s from %s: %s", p.event_id, origin, e
                 )
 
@@ -1250,7 +1281,7 @@ class FederationHandler(BaseHandler):
                 builder=builder
             )
         except AuthError as e:
-            logger.warn("Failed to create join %r because %s", event, e)
+            logger.warning("Failed to create join to %s because %s", room_id, e)
             raise e
 
         event_allowed = yield self.third_party_event_rules.check_event_allowed(
@@ -1494,7 +1525,7 @@ class FederationHandler(BaseHandler):
                 room_version, event, context, do_sig_check=False
             )
         except AuthError as e:
-            logger.warn("Failed to create new leave %r because %s", event, e)
+            logger.warning("Failed to create new leave %r because %s", event, e)
             raise e
 
         return event
@@ -1549,7 +1580,7 @@ class FederationHandler(BaseHandler):
             event_id, allow_none=False, check_room_id=room_id
         )
 
-        state_groups = yield self.store.get_state_groups(room_id, [event_id])
+        state_groups = yield self.state_store.get_state_groups(room_id, [event_id])
 
         if state_groups:
             _, state = list(iteritems(state_groups)).pop()
@@ -1578,7 +1609,7 @@ class FederationHandler(BaseHandler):
             event_id, allow_none=False, check_room_id=room_id
         )
 
-        state_groups = yield self.store.get_state_groups_ids(room_id, [event_id])
+        state_groups = yield self.state_store.get_state_groups_ids(room_id, [event_id])
 
         if state_groups:
             _, state = list(state_groups.items()).pop()
@@ -1606,7 +1637,7 @@ class FederationHandler(BaseHandler):
 
         events = yield self.store.get_backfill_events(room_id, pdu_list, limit)
 
-        events = yield filter_events_for_server(self.store, origin, events)
+        events = yield filter_events_for_server(self.storage, origin, events)
 
         return events
 
@@ -1636,7 +1667,7 @@ class FederationHandler(BaseHandler):
             if not in_room:
                 raise AuthError(403, "Host not in room.")
 
-            events = yield filter_events_for_server(self.store, origin, [event])
+            events = yield filter_events_for_server(self.storage, origin, [event])
             event = events[0]
             return event
         else:
@@ -1788,7 +1819,7 @@ class FederationHandler(BaseHandler):
                 # cause SynapseErrors in auth.check. We don't want to give up
                 # the attempt to federate altogether in such cases.
 
-                logger.warn("Rejecting %s because %s", e.event_id, err.msg)
+                logger.warning("Rejecting %s because %s", e.event_id, err.msg)
 
                 if e == event:
                     raise
@@ -1841,12 +1872,7 @@ class FederationHandler(BaseHandler):
                 if c and c.type == EventTypes.Create:
                     auth_events[(c.type, c.state_key)] = c
 
-        try:
-            yield self.do_auth(origin, event, context, auth_events=auth_events)
-        except AuthError as e:
-            logger.warn("[%s %s] Rejecting: %s", event.room_id, event.event_id, e.msg)
-
-            context.rejected = RejectedReason.AUTH_ERROR
+        context = yield self.do_auth(origin, event, context, auth_events=auth_events)
 
         if not context.rejected:
             yield self._check_for_soft_fail(event, state, backfilled)
@@ -1902,7 +1928,7 @@ class FederationHandler(BaseHandler):
                 # given state at the event. This should correctly handle cases
                 # like bans, especially with state res v2.
 
-                state_sets = yield self.store.get_state_groups(
+                state_sets = yield self.state_store.get_state_groups(
                     event.room_id, extrem_ids
                 )
                 state_sets = list(state_sets.values())
@@ -1938,7 +1964,7 @@ class FederationHandler(BaseHandler):
             try:
                 event_auth.check(room_version, event, auth_events=current_auth_events)
             except AuthError as e:
-                logger.warn("Soft-failing %r because %s", event, e)
+                logger.warning("Soft-failing %r because %s", event, e)
                 event.internal_metadata.soft_failed = True
 
     @defer.inlineCallbacks
@@ -1993,7 +2019,7 @@ class FederationHandler(BaseHandler):
         )
 
         missing_events = yield filter_events_for_server(
-            self.store, origin, missing_events
+            self.storage, origin, missing_events
         )
 
         return missing_events
@@ -2015,12 +2041,12 @@ class FederationHandler(BaseHandler):
 
                 Also NB that this function adds entries to it.
         Returns:
-            defer.Deferred[None]
+            defer.Deferred[EventContext]: updated context object
         """
         room_version = yield self.store.get_room_version(event.room_id)
 
         try:
-            yield self._update_auth_events_and_context_for_auth(
+            context = yield self._update_auth_events_and_context_for_auth(
                 origin, event, context, auth_events
             )
         except Exception:
@@ -2037,8 +2063,10 @@ class FederationHandler(BaseHandler):
         try:
             event_auth.check(room_version, event, auth_events=auth_events)
         except AuthError as e:
-            logger.warn("Failed auth resolution for %r because %s", event, e)
-            raise e
+            logger.warning("Failed auth resolution for %r because %s", event, e)
+            context.rejected = RejectedReason.AUTH_ERROR
+
+        return context
 
     @defer.inlineCallbacks
     def _update_auth_events_and_context_for_auth(
@@ -2062,7 +2090,7 @@ class FederationHandler(BaseHandler):
             auth_events (dict[(str, str)->synapse.events.EventBase]):
 
         Returns:
-            defer.Deferred[None]
+            defer.Deferred[EventContext]: updated context
         """
         event_auth_events = set(event.auth_event_ids())
 
@@ -2101,7 +2129,7 @@ class FederationHandler(BaseHandler):
                     # The other side isn't around or doesn't implement the
                     # endpoint, so lets just bail out.
                     logger.info("Failed to get event auth from remote: %s", e)
-                    return
+                    return context
 
                 seen_remotes = yield self.store.have_seen_events(
                     [e.event_id for e in remote_auth_chain]
@@ -2142,7 +2170,7 @@ class FederationHandler(BaseHandler):
 
         if event.internal_metadata.is_outlier():
             logger.info("Skipping auth_event fetch for outlier")
-            return
+            return context
 
         # FIXME: Assumes we have and stored all the state for all the
         # prev_events
@@ -2151,7 +2179,7 @@ class FederationHandler(BaseHandler):
         )
 
         if not different_auth:
-            return
+            return context
 
         logger.info(
             "auth_events refers to events which are not in our calculated auth "
@@ -2198,10 +2226,12 @@ class FederationHandler(BaseHandler):
 
             auth_events.update(new_state)
 
-            yield self._update_context_for_auth_events(
+            context = yield self._update_context_for_auth_events(
                 event, context, auth_events, event_key
             )
 
+        return context
+
     @defer.inlineCallbacks
     def _update_context_for_auth_events(self, event, context, auth_events, event_key):
         """Update the state_ids in an event context after auth event resolution,
@@ -2210,14 +2240,16 @@ class FederationHandler(BaseHandler):
         Args:
             event (Event): The event we're handling the context for
 
-            context (synapse.events.snapshot.EventContext): event context
-                to be updated
+            context (synapse.events.snapshot.EventContext): initial event context
 
             auth_events (dict[(str, str)->str]): Events to update in the event
                 context.
 
             event_key ((str, str)): (type, state_key) for the current event.
                 this will not be included in the current_state in the context.
+
+        Returns:
+            Deferred[EventContext]: new event context
         """
         state_updates = {
             k: a.event_id for k, a in iteritems(auth_events) if k != event_key
@@ -2234,7 +2266,7 @@ class FederationHandler(BaseHandler):
 
         # create a new state group as a delta from the existing one.
         prev_group = context.state_group
-        state_group = yield self.store.store_state_group(
+        state_group = yield self.state_store.store_state_group(
             event.event_id,
             event.room_id,
             prev_group=prev_group,
@@ -2242,7 +2274,7 @@ class FederationHandler(BaseHandler):
             current_state_ids=current_state_ids,
         )
 
-        yield context.update_state(
+        return EventContext.with_state(
             state_group=state_group,
             current_state_ids=current_state_ids,
             prev_state_ids=prev_state_ids,
@@ -2431,10 +2463,12 @@ class FederationHandler(BaseHandler):
             try:
                 yield self.auth.check_from_context(room_version, event, context)
             except AuthError as e:
-                logger.warn("Denying new third party invite %r because %s", event, e)
+                logger.warning("Denying new third party invite %r because %s", event, e)
                 raise e
 
             yield self._check_signature(event, context)
+
+            # We retrieve the room member handler here as to not cause a cyclic dependency
             member_handler = self.hs.get_room_member_handler()
             yield member_handler.send_membership_event(None, event, context)
         else:
@@ -2487,7 +2521,7 @@ class FederationHandler(BaseHandler):
         try:
             yield self.auth.check_from_context(room_version, event, context)
         except AuthError as e:
-            logger.warn("Denying third party invite %r because %s", event, e)
+            logger.warning("Denying third party invite %r because %s", event, e)
             raise e
         yield self._check_signature(event, context)
 
@@ -2495,6 +2529,7 @@ class FederationHandler(BaseHandler):
         # though the sender isn't a local user.
         event.internal_metadata.send_on_behalf_of = get_domain_from_id(event.sender)
 
+        # We retrieve the room member handler here as to not cause a cyclic dependency
         member_handler = self.hs.get_room_member_handler()
         yield member_handler.send_membership_event(None, event, context)
 
@@ -2664,7 +2699,7 @@ class FederationHandler(BaseHandler):
                 backfilled=backfilled,
             )
         else:
-            max_stream_id = yield self.store.persist_events(
+            max_stream_id = yield self.storage.persistence.persist_events(
                 event_and_contexts, backfilled=backfilled
             )
 
diff --git a/synapse/handlers/groups_local.py b/synapse/handlers/groups_local.py
index 46eb9ee88b..92fecbfc44 100644
--- a/synapse/handlers/groups_local.py
+++ b/synapse/handlers/groups_local.py
@@ -392,7 +392,7 @@ class GroupsLocalHandler(object):
         try:
             user_profile = yield self.profile_handler.get_profile(user_id)
         except Exception as e:
-            logger.warn("No profile for user %s: %s", user_id, e)
+            logger.warning("No profile for user %s: %s", user_id, e)
             user_profile = {}
 
         return {"state": "invite", "user_profile": user_profile}
diff --git a/synapse/handlers/identity.py b/synapse/handlers/identity.py
index ba99ddf76d..000fbf090f 100644
--- a/synapse/handlers/identity.py
+++ b/synapse/handlers/identity.py
@@ -272,7 +272,7 @@ class IdentityHandler(BaseHandler):
             changed = False
             if e.code in (400, 404, 501):
                 # The remote server probably doesn't support unbinding (yet)
-                logger.warn("Received %d response while unbinding threepid", e.code)
+                logger.warning("Received %d response while unbinding threepid", e.code)
             else:
                 logger.error("Failed to unbind threepid on identity server: %s", e)
                 raise SynapseError(500, "Failed to contact identity server")
@@ -403,7 +403,7 @@ class IdentityHandler(BaseHandler):
 
         if self.hs.config.using_identity_server_from_trusted_list:
             # Warn that a deprecated config option is in use
-            logger.warn(
+            logger.warning(
                 'The config option "trust_identity_server_for_password_resets" '
                 'has been replaced by "account_threepid_delegate". '
                 "Please consult the sample config at docs/sample_config.yaml for "
@@ -457,7 +457,7 @@ class IdentityHandler(BaseHandler):
 
         if self.hs.config.using_identity_server_from_trusted_list:
             # Warn that a deprecated config option is in use
-            logger.warn(
+            logger.warning(
                 'The config option "trust_identity_server_for_password_resets" '
                 'has been replaced by "account_threepid_delegate". '
                 "Please consult the sample config at docs/sample_config.yaml for "
diff --git a/synapse/handlers/initial_sync.py b/synapse/handlers/initial_sync.py
index f991efeee3..81dce96f4b 100644
--- a/synapse/handlers/initial_sync.py
+++ b/synapse/handlers/initial_sync.py
@@ -43,6 +43,8 @@ class InitialSyncHandler(BaseHandler):
         self.validator = EventValidator()
         self.snapshot_cache = SnapshotCache()
         self._event_serializer = hs.get_event_client_serializer()
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
 
     def snapshot_all_rooms(
         self,
@@ -126,8 +128,8 @@ class InitialSyncHandler(BaseHandler):
 
         tags_by_room = yield self.store.get_tags_for_user(user_id)
 
-        account_data, account_data_by_room = (
-            yield self.store.get_account_data_for_user(user_id)
+        account_data, account_data_by_room = yield self.store.get_account_data_for_user(
+            user_id
         )
 
         public_room_ids = yield self.store.get_public_room_ids()
@@ -169,7 +171,7 @@ class InitialSyncHandler(BaseHandler):
                 elif event.membership == Membership.LEAVE:
                     room_end_token = "s%d" % (event.stream_ordering,)
                     deferred_room_state = run_in_background(
-                        self.store.get_state_for_events, [event.event_id]
+                        self.state_store.get_state_for_events, [event.event_id]
                     )
                     deferred_room_state.addCallback(
                         lambda states: states[event.event_id]
@@ -189,7 +191,9 @@ class InitialSyncHandler(BaseHandler):
                     )
                 ).addErrback(unwrapFirstError)
 
-                messages = yield filter_events_for_client(self.store, user_id, messages)
+                messages = yield filter_events_for_client(
+                    self.storage, user_id, messages
+                )
 
                 start_token = now_token.copy_and_replace("room_key", token)
                 end_token = now_token.copy_and_replace("room_key", room_end_token)
@@ -307,7 +311,7 @@ class InitialSyncHandler(BaseHandler):
     def _room_initial_sync_parted(
         self, user_id, room_id, pagin_config, membership, member_event_id, is_peeking
     ):
-        room_state = yield self.store.get_state_for_events([member_event_id])
+        room_state = yield self.state_store.get_state_for_events([member_event_id])
 
         room_state = room_state[member_event_id]
 
@@ -322,7 +326,7 @@ class InitialSyncHandler(BaseHandler):
         )
 
         messages = yield filter_events_for_client(
-            self.store, user_id, messages, is_peeking=is_peeking
+            self.storage, user_id, messages, is_peeking=is_peeking
         )
 
         start_token = StreamToken.START.copy_and_replace("room_key", token)
@@ -414,7 +418,7 @@ class InitialSyncHandler(BaseHandler):
         )
 
         messages = yield filter_events_for_client(
-            self.store, user_id, messages, is_peeking=is_peeking
+            self.storage, user_id, messages, is_peeking=is_peeking
         )
 
         start_token = now_token.copy_and_replace("room_key", token)
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 0f8cce8ffe..d682dc2b7a 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -59,6 +59,8 @@ class MessageHandler(object):
         self.clock = hs.get_clock()
         self.state = hs.get_state_handler()
         self.store = hs.get_datastore()
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
         self._event_serializer = hs.get_event_client_serializer()
 
     @defer.inlineCallbacks
@@ -74,15 +76,16 @@ class MessageHandler(object):
         Raises:
             SynapseError if something went wrong.
         """
-        membership, membership_event_id = yield self.auth.check_in_room_or_world_readable(
-            room_id, user_id
-        )
+        (
+            membership,
+            membership_event_id,
+        ) = yield self.auth.check_in_room_or_world_readable(room_id, user_id)
 
         if membership == Membership.JOIN:
             data = yield self.state.get_current_state(room_id, event_type, state_key)
         elif membership == Membership.LEAVE:
             key = (event_type, state_key)
-            room_state = yield self.store.get_state_for_events(
+            room_state = yield self.state_store.get_state_for_events(
                 [membership_event_id], StateFilter.from_types([key])
             )
             data = room_state[membership_event_id].get(key)
@@ -135,12 +138,12 @@ class MessageHandler(object):
                 raise NotFoundError("Can't find event for token %s" % (at_token,))
 
             visible_events = yield filter_events_for_client(
-                self.store, user_id, last_events
+                self.storage, user_id, last_events
             )
 
             event = last_events[0]
             if visible_events:
-                room_state = yield self.store.get_state_for_events(
+                room_state = yield self.state_store.get_state_for_events(
                     [event.event_id], state_filter=state_filter
                 )
                 room_state = room_state[event.event_id]
@@ -151,9 +154,10 @@ class MessageHandler(object):
                     % (user_id, room_id, at_token),
                 )
         else:
-            membership, membership_event_id = (
-                yield self.auth.check_in_room_or_world_readable(room_id, user_id)
-            )
+            (
+                membership,
+                membership_event_id,
+            ) = yield self.auth.check_in_room_or_world_readable(room_id, user_id)
 
             if membership == Membership.JOIN:
                 state_ids = yield self.store.get_filtered_current_state_ids(
@@ -161,7 +165,7 @@ class MessageHandler(object):
                 )
                 room_state = yield self.store.get_events(state_ids.values())
             elif membership == Membership.LEAVE:
-                room_state = yield self.store.get_state_for_events(
+                room_state = yield self.state_store.get_state_for_events(
                     [membership_event_id], state_filter=state_filter
                 )
                 room_state = room_state[membership_event_id]
@@ -234,6 +238,7 @@ class EventCreationHandler(object):
         self.hs = hs
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
+        self.storage = hs.get_storage()
         self.state = hs.get_state_handler()
         self.clock = hs.get_clock()
         self.validator = EventValidator()
@@ -687,7 +692,7 @@ class EventCreationHandler(object):
         try:
             yield self.auth.check_from_context(room_version, event, context)
         except AuthError as err:
-            logger.warn("Denying new event %r because %s", event, err)
+            logger.warning("Denying new event %r because %s", event, err)
             raise err
 
         # Ensure that we can round trip before trying to persist in db
@@ -868,7 +873,7 @@ class EventCreationHandler(object):
             if prev_state_ids:
                 raise AuthError(403, "Changing the room create event is forbidden")
 
-        (event_stream_id, max_stream_id) = yield self.store.persist_event(
+        event_stream_id, max_stream_id = yield self.storage.persistence.persist_event(
             event, context=context
         )
 
diff --git a/synapse/handlers/pagination.py b/synapse/handlers/pagination.py
index 5744f4579d..97f15a1c32 100644
--- a/synapse/handlers/pagination.py
+++ b/synapse/handlers/pagination.py
@@ -69,6 +69,8 @@ class PaginationHandler(object):
         self.hs = hs
         self.auth = hs.get_auth()
         self.store = hs.get_datastore()
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
         self.clock = hs.get_clock()
         self._server_name = hs.hostname
 
@@ -210,9 +212,10 @@ class PaginationHandler(object):
         source_config = pagin_config.get_source_config("room")
 
         with (yield self.pagination_lock.read(room_id)):
-            membership, member_event_id = yield self.auth.check_in_room_or_world_readable(
-                room_id, user_id
-            )
+            (
+                membership,
+                member_event_id,
+            ) = yield self.auth.check_in_room_or_world_readable(room_id, user_id)
 
             if source_config.direction == "b":
                 # if we're going backwards, we might need to backfill. This
@@ -255,7 +258,7 @@ class PaginationHandler(object):
                 events = event_filter.filter(events)
 
             events = yield filter_events_for_client(
-                self.store, user_id, events, is_peeking=(member_event_id is None)
+                self.storage, user_id, events, is_peeking=(member_event_id is None)
             )
 
         if not events:
@@ -274,7 +277,7 @@ class PaginationHandler(object):
                 (EventTypes.Member, event.sender) for event in events
             )
 
-            state_ids = yield self.store.get_state_ids_for_event(
+            state_ids = yield self.state_store.get_state_ids_for_event(
                 events[0].event_id, state_filter=state_filter
             )
 
@@ -295,10 +298,8 @@ class PaginationHandler(object):
         }
 
         if state:
-            chunk["state"] = (
-                yield self._event_serializer.serialize_events(
-                    state, time_now, as_client_event=as_client_event
-                )
+            chunk["state"] = yield self._event_serializer.serialize_events(
+                state, time_now, as_client_event=as_client_event
             )
 
         return chunk
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 8690f69d45..22e0a04da4 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -275,7 +275,7 @@ class BaseProfileHandler(BaseHandler):
                     ratelimit=False,  # Try to hide that these events aren't atomic.
                 )
             except Exception as e:
-                logger.warn(
+                logger.warning(
                     "Failed to update join event for room %s - %s", room_id, str(e)
                 )
 
diff --git a/synapse/handlers/read_marker.py b/synapse/handlers/read_marker.py
index 3e4d8c93a4..e3b528d271 100644
--- a/synapse/handlers/read_marker.py
+++ b/synapse/handlers/read_marker.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.util.async_helpers import Linearizer
 
 from ._base import BaseHandler
@@ -32,8 +30,7 @@ class ReadMarkerHandler(BaseHandler):
         self.read_marker_linearizer = Linearizer(name="read_marker")
         self.notifier = hs.get_notifier()
 
-    @defer.inlineCallbacks
-    def received_client_read_marker(self, room_id, user_id, event_id):
+    async def received_client_read_marker(self, room_id, user_id, event_id):
         """Updates the read marker for a given user in a given room if the event ID given
         is ahead in the stream relative to the current read marker.
 
@@ -41,8 +38,8 @@ class ReadMarkerHandler(BaseHandler):
         the read marker has changed.
         """
 
-        with (yield self.read_marker_linearizer.queue((room_id, user_id))):
-            existing_read_marker = yield self.store.get_account_data_for_room_and_type(
+        with await self.read_marker_linearizer.queue((room_id, user_id)):
+            existing_read_marker = await self.store.get_account_data_for_room_and_type(
                 user_id, room_id, "m.fully_read"
             )
 
@@ -50,13 +47,13 @@ class ReadMarkerHandler(BaseHandler):
 
             if existing_read_marker:
                 # Only update if the new marker is ahead in the stream
-                should_update = yield self.store.is_event_after(
+                should_update = await self.store.is_event_after(
                     event_id, existing_read_marker["event_id"]
                 )
 
             if should_update:
                 content = {"event_id": event_id}
-                max_id = yield self.store.add_account_data_to_room(
+                max_id = await self.store.add_account_data_to_room(
                     user_id, room_id, "m.fully_read", content
                 )
                 self.notifier.on_new_event("account_data_key", max_id, users=[user_id])
diff --git a/synapse/handlers/receipts.py b/synapse/handlers/receipts.py
index 6854c751a6..9283c039e3 100644
--- a/synapse/handlers/receipts.py
+++ b/synapse/handlers/receipts.py
@@ -18,6 +18,7 @@ from twisted.internet import defer
 
 from synapse.handlers._base import BaseHandler
 from synapse.types import ReadReceipt, get_domain_from_id
+from synapse.util.async_helpers import maybe_awaitable
 
 logger = logging.getLogger(__name__)
 
@@ -36,8 +37,7 @@ class ReceiptsHandler(BaseHandler):
         self.clock = self.hs.get_clock()
         self.state = hs.get_state_handler()
 
-    @defer.inlineCallbacks
-    def _received_remote_receipt(self, origin, content):
+    async def _received_remote_receipt(self, origin, content):
         """Called when we receive an EDU of type m.receipt from a remote HS.
         """
         receipts = []
@@ -62,17 +62,16 @@ class ReceiptsHandler(BaseHandler):
                         )
                     )
 
-        yield self._handle_new_receipts(receipts)
+        await self._handle_new_receipts(receipts)
 
-    @defer.inlineCallbacks
-    def _handle_new_receipts(self, receipts):
+    async def _handle_new_receipts(self, receipts):
         """Takes a list of receipts, stores them and informs the notifier.
         """
         min_batch_id = None
         max_batch_id = None
 
         for receipt in receipts:
-            res = yield self.store.insert_receipt(
+            res = await self.store.insert_receipt(
                 receipt.room_id,
                 receipt.receipt_type,
                 receipt.user_id,
@@ -99,14 +98,15 @@ class ReceiptsHandler(BaseHandler):
 
         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.
-        yield self.hs.get_pusherpool().on_new_receipts(
-            min_batch_id, max_batch_id, affected_room_ids
+        await maybe_awaitable(
+            self.hs.get_pusherpool().on_new_receipts(
+                min_batch_id, max_batch_id, affected_room_ids
+            )
         )
 
         return True
 
-    @defer.inlineCallbacks
-    def received_client_receipt(self, room_id, receipt_type, user_id, event_id):
+    async def received_client_receipt(self, room_id, receipt_type, user_id, event_id):
         """Called when a client tells us a local user has read up to the given
         event_id in the room.
         """
@@ -118,24 +118,11 @@ class ReceiptsHandler(BaseHandler):
             data={"ts": int(self.clock.time_msec())},
         )
 
-        is_new = yield self._handle_new_receipts([receipt])
+        is_new = await self._handle_new_receipts([receipt])
         if not is_new:
             return
 
-        yield self.federation.send_read_receipt(receipt)
-
-    @defer.inlineCallbacks
-    def get_receipts_for_room(self, room_id, to_key):
-        """Gets all receipts for a room, upto the given key.
-        """
-        result = yield self.store.get_linearized_receipts_for_room(
-            room_id, to_key=to_key
-        )
-
-        if not result:
-            return []
-
-        return result
+        await self.federation.send_read_receipt(receipt)
 
 
 class ReceiptEventSource(object):
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 53410f120b..cff6b0d375 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -396,8 +396,8 @@ class RegistrationHandler(BaseHandler):
             room_id = room_identifier
         elif RoomAlias.is_valid(room_identifier):
             room_alias = RoomAlias.from_string(room_identifier)
-            room_id, remote_room_hosts = (
-                yield room_member_handler.lookup_room_alias(room_alias)
+            room_id, remote_room_hosts = yield room_member_handler.lookup_room_alias(
+                room_alias
             )
             room_id = room_id.to_string()
         else:
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 2816bd8f87..e92b2eafd5 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -129,6 +129,7 @@ class RoomCreationHandler(BaseHandler):
             old_room_id,
             new_version,  # args for _upgrade_room
         )
+
         return ret
 
     @defer.inlineCallbacks
@@ -147,21 +148,22 @@ class RoomCreationHandler(BaseHandler):
 
         # we create and auth the tombstone event before properly creating the new
         # room, to check our user has perms in the old room.
-        tombstone_event, tombstone_context = (
-            yield self.event_creation_handler.create_event(
-                requester,
-                {
-                    "type": EventTypes.Tombstone,
-                    "state_key": "",
-                    "room_id": old_room_id,
-                    "sender": user_id,
-                    "content": {
-                        "body": "This room has been replaced",
-                        "replacement_room": new_room_id,
-                    },
+        (
+            tombstone_event,
+            tombstone_context,
+        ) = yield self.event_creation_handler.create_event(
+            requester,
+            {
+                "type": EventTypes.Tombstone,
+                "state_key": "",
+                "room_id": old_room_id,
+                "sender": user_id,
+                "content": {
+                    "body": "This room has been replaced",
+                    "replacement_room": new_room_id,
                 },
-                token_id=requester.access_token_id,
-            )
+            },
+            token_id=requester.access_token_id,
         )
         old_room_version = yield self.store.get_room_version(old_room_id)
         yield self.auth.check_from_context(
@@ -188,7 +190,12 @@ class RoomCreationHandler(BaseHandler):
             requester, old_room_id, new_room_id, old_room_state
         )
 
-        # and finally, shut down the PLs in the old room, and update them in the new
+        # Copy over user push rules, tags and migrate room directory state
+        yield self.room_member_handler.transfer_room_state_on_room_upgrade(
+            old_room_id, new_room_id
+        )
+
+        # finally, shut down the PLs in the old room, and update them in the new
         # room.
         yield self._update_upgraded_room_pls(
             requester, old_room_id, new_room_id, old_room_state
@@ -822,6 +829,8 @@ class RoomContextHandler(object):
     def __init__(self, hs):
         self.hs = hs
         self.store = hs.get_datastore()
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
 
     @defer.inlineCallbacks
     def get_event_context(self, user, room_id, event_id, limit, event_filter):
@@ -848,7 +857,7 @@ class RoomContextHandler(object):
 
         def filter_evts(events):
             return filter_events_for_client(
-                self.store, user.to_string(), events, is_peeking=is_peeking
+                self.storage, user.to_string(), events, is_peeking=is_peeking
             )
 
         event = yield self.store.get_event(
@@ -890,7 +899,7 @@ class RoomContextHandler(object):
         # first? Shouldn't we be consistent with /sync?
         # https://github.com/matrix-org/matrix-doc/issues/687
 
-        state = yield self.store.get_state_for_events(
+        state = yield self.state_store.get_state_for_events(
             [last_event_id], state_filter=state_filter
         )
         results["state"] = list(state[last_event_id].values())
@@ -922,7 +931,7 @@ class RoomEventSource(object):
 
         from_token = RoomStreamToken.parse(from_key)
         if from_token.topological:
-            logger.warn("Stream has topological part!!!! %r", from_key)
+            logger.warning("Stream has topological part!!!! %r", from_key)
             from_key = "s%s" % (from_token.stream,)
 
         app_service = self.store.get_app_service_by_user_id(user.to_string())
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 380e2fad5e..06d09c2947 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -203,10 +203,6 @@ class RoomMemberHandler(object):
                 prev_member_event = yield self.store.get_event(prev_member_event_id)
                 newly_joined = prev_member_event.membership != Membership.JOIN
             if newly_joined:
-                # Copy over user state if we're joining an upgraded room
-                yield self.copy_user_state_if_room_upgrade(
-                    room_id, requester.user.to_string()
-                )
                 yield self._user_joined_room(target, room_id)
         elif event.membership == Membership.LEAVE:
             if prev_member_event_id:
@@ -455,11 +451,6 @@ class RoomMemberHandler(object):
                     requester, remote_room_hosts, room_id, target, content
                 )
 
-                # Copy over user state if this is a join on an remote upgraded room
-                yield self.copy_user_state_if_room_upgrade(
-                    room_id, requester.user.to_string()
-                )
-
                 return remote_join_response
 
         elif effective_membership_state == Membership.LEAVE:
@@ -498,36 +489,72 @@ class RoomMemberHandler(object):
         return res
 
     @defer.inlineCallbacks
-    def copy_user_state_if_room_upgrade(self, new_room_id, user_id):
-        """Copy user-specific information when they join a new room if that new room is the
+    def transfer_room_state_on_room_upgrade(self, old_room_id, room_id):
+        """Upon our server becoming aware of an upgraded room, either by upgrading a room
+        ourselves or joining one, we can transfer over information from the previous room.
+
+        Copies user state (tags/push rules) for every local user that was in the old room, as
+        well as migrating the room directory state.
+
+        Args:
+            old_room_id (str): The ID of the old room
+
+            room_id (str): The ID of the new room
+
+        Returns:
+            Deferred
+        """
+        # Find all local users that were in the old room and copy over each user's state
+        users = yield self.store.get_users_in_room(old_room_id)
+        yield self.copy_user_state_on_room_upgrade(old_room_id, room_id, users)
+
+        # Add new room to the room directory if the old room was there
+        # Remove old room from the room directory
+        old_room = yield self.store.get_room(old_room_id)
+        if old_room and old_room["is_public"]:
+            yield self.store.set_room_is_public(old_room_id, False)
+            yield self.store.set_room_is_public(room_id, True)
+
+    @defer.inlineCallbacks
+    def copy_user_state_on_room_upgrade(self, old_room_id, new_room_id, user_ids):
+        """Copy user-specific information when they join a new room when that new room is the
         result of a room upgrade
 
         Args:
-            new_room_id (str): The ID of the room the user is joining
-            user_id (str): The ID of the user
+            old_room_id (str): The ID of upgraded room
+            new_room_id (str): The ID of the new room
+            user_ids (Iterable[str]): User IDs to copy state for
 
         Returns:
             Deferred
         """
-        # Check if the new room is an upgraded room
-        predecessor = yield self.store.get_room_predecessor(new_room_id)
-        if not predecessor:
-            return
 
         logger.debug(
-            "Found predecessor for %s: %s. Copying over room tags and push " "rules",
+            "Copying over room tags and push rules from %s to %s for users %s",
+            old_room_id,
             new_room_id,
-            predecessor,
+            user_ids,
         )
 
-        # It is an upgraded room. Copy over old tags
-        yield self.copy_room_tags_and_direct_to_room(
-            predecessor["room_id"], new_room_id, user_id
-        )
-        # Copy over push rules
-        yield self.store.copy_push_rules_from_room_to_room_for_user(
-            predecessor["room_id"], new_room_id, user_id
-        )
+        for user_id in user_ids:
+            try:
+                # It is an upgraded room. Copy over old tags
+                yield self.copy_room_tags_and_direct_to_room(
+                    old_room_id, new_room_id, user_id
+                )
+                # Copy over push rules
+                yield self.store.copy_push_rules_from_room_to_room_for_user(
+                    old_room_id, new_room_id, user_id
+                )
+            except Exception:
+                logger.exception(
+                    "Error copying tags and/or push rules from rooms %s to %s for user %s. "
+                    "Skipping...",
+                    old_room_id,
+                    new_room_id,
+                    user_id,
+                )
+                continue
 
     @defer.inlineCallbacks
     def send_membership_event(self, requester, event, context, ratelimit=True):
@@ -759,22 +786,25 @@ class RoomMemberHandler(object):
         if room_avatar_event:
             room_avatar_url = room_avatar_event.content.get("url", "")
 
-        token, public_keys, fallback_public_key, display_name = (
-            yield self.identity_handler.ask_id_server_for_third_party_invite(
-                requester=requester,
-                id_server=id_server,
-                medium=medium,
-                address=address,
-                room_id=room_id,
-                inviter_user_id=user.to_string(),
-                room_alias=canonical_room_alias,
-                room_avatar_url=room_avatar_url,
-                room_join_rules=room_join_rules,
-                room_name=room_name,
-                inviter_display_name=inviter_display_name,
-                inviter_avatar_url=inviter_avatar_url,
-                id_access_token=id_access_token,
-            )
+        (
+            token,
+            public_keys,
+            fallback_public_key,
+            display_name,
+        ) = yield self.identity_handler.ask_id_server_for_third_party_invite(
+            requester=requester,
+            id_server=id_server,
+            medium=medium,
+            address=address,
+            room_id=room_id,
+            inviter_user_id=user.to_string(),
+            room_alias=canonical_room_alias,
+            room_avatar_url=room_avatar_url,
+            room_join_rules=room_join_rules,
+            room_name=room_name,
+            inviter_display_name=inviter_display_name,
+            inviter_avatar_url=inviter_avatar_url,
+            id_access_token=id_access_token,
         )
 
         yield self.event_creation_handler.create_and_send_nonmember_event(
diff --git a/synapse/handlers/search.py b/synapse/handlers/search.py
index cd5e90bacb..56ed262a1f 100644
--- a/synapse/handlers/search.py
+++ b/synapse/handlers/search.py
@@ -35,6 +35,8 @@ class SearchHandler(BaseHandler):
     def __init__(self, hs):
         super(SearchHandler, self).__init__(hs)
         self._event_serializer = hs.get_event_client_serializer()
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
 
     @defer.inlineCallbacks
     def get_old_rooms_from_upgraded_room(self, room_id):
@@ -221,7 +223,7 @@ class SearchHandler(BaseHandler):
             filtered_events = search_filter.filter([r["event"] for r in results])
 
             events = yield filter_events_for_client(
-                self.store, user.to_string(), filtered_events
+                self.storage, user.to_string(), filtered_events
             )
 
             events.sort(key=lambda e: -rank_map[e.event_id])
@@ -271,7 +273,7 @@ class SearchHandler(BaseHandler):
                 filtered_events = search_filter.filter([r["event"] for r in results])
 
                 events = yield filter_events_for_client(
-                    self.store, user.to_string(), filtered_events
+                    self.storage, user.to_string(), filtered_events
                 )
 
                 room_events.extend(events)
@@ -340,11 +342,11 @@ class SearchHandler(BaseHandler):
                 )
 
                 res["events_before"] = yield filter_events_for_client(
-                    self.store, user.to_string(), res["events_before"]
+                    self.storage, user.to_string(), res["events_before"]
                 )
 
                 res["events_after"] = yield filter_events_for_client(
-                    self.store, user.to_string(), res["events_after"]
+                    self.storage, user.to_string(), res["events_after"]
                 )
 
                 res["start"] = now_token.copy_and_replace(
@@ -372,7 +374,7 @@ class SearchHandler(BaseHandler):
                         [(EventTypes.Member, sender) for sender in senders]
                     )
 
-                    state = yield self.store.get_state_for_event(
+                    state = yield self.state_store.get_state_for_event(
                         last_event_id, state_filter
                     )
 
@@ -394,15 +396,11 @@ class SearchHandler(BaseHandler):
         time_now = self.clock.time_msec()
 
         for context in contexts.values():
-            context["events_before"] = (
-                yield self._event_serializer.serialize_events(
-                    context["events_before"], time_now
-                )
+            context["events_before"] = yield self._event_serializer.serialize_events(
+                context["events_before"], time_now
             )
-            context["events_after"] = (
-                yield self._event_serializer.serialize_events(
-                    context["events_after"], time_now
-                )
+            context["events_after"] = yield self._event_serializer.serialize_events(
+                context["events_after"], time_now
             )
 
         state_results = {}
diff --git a/synapse/handlers/stats.py b/synapse/handlers/stats.py
index 26bc276692..7f7d56390e 100644
--- a/synapse/handlers/stats.py
+++ b/synapse/handlers/stats.py
@@ -108,7 +108,10 @@ class StatsHandler(StateDeltasHandler):
                 user_deltas = {}
 
             # Then count deltas for total_events and total_event_bytes.
-            room_count, user_count = yield self.store.get_changes_room_total_events_and_bytes(
+            (
+                room_count,
+                user_count,
+            ) = yield self.store.get_changes_room_total_events_and_bytes(
                 self.pos, max_pos
             )
 
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index d99160e9d7..b536d410e5 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -230,6 +230,8 @@ class SyncHandler(object):
         self.response_cache = ResponseCache(hs, "sync")
         self.state = hs.get_state_handler()
         self.auth = hs.get_auth()
+        self.storage = hs.get_storage()
+        self.state_store = self.storage.state
 
         # ExpiringCache((User, Device)) -> LruCache(state_key => event_id)
         self.lazy_loaded_members_cache = ExpiringCache(
@@ -417,7 +419,7 @@ class SyncHandler(object):
                     current_state_ids = frozenset(itervalues(current_state_ids))
 
                 recents = yield filter_events_for_client(
-                    self.store,
+                    self.storage,
                     sync_config.user.to_string(),
                     recents,
                     always_include_ids=current_state_ids,
@@ -470,7 +472,7 @@ class SyncHandler(object):
                     current_state_ids = frozenset(itervalues(current_state_ids))
 
                 loaded_recents = yield filter_events_for_client(
-                    self.store,
+                    self.storage,
                     sync_config.user.to_string(),
                     loaded_recents,
                     always_include_ids=current_state_ids,
@@ -509,7 +511,7 @@ class SyncHandler(object):
         Returns:
             A Deferred map from ((type, state_key)->Event)
         """
-        state_ids = yield self.store.get_state_ids_for_event(
+        state_ids = yield self.state_store.get_state_ids_for_event(
             event.event_id, state_filter=state_filter
         )
         if event.is_state():
@@ -580,7 +582,7 @@ class SyncHandler(object):
             return None
 
         last_event = last_events[-1]
-        state_ids = yield self.store.get_state_ids_for_event(
+        state_ids = yield self.state_store.get_state_ids_for_event(
             last_event.event_id,
             state_filter=StateFilter.from_types(
                 [(EventTypes.Name, ""), (EventTypes.CanonicalAlias, "")]
@@ -757,11 +759,11 @@ class SyncHandler(object):
 
             if full_state:
                 if batch:
-                    current_state_ids = yield self.store.get_state_ids_for_event(
+                    current_state_ids = yield self.state_store.get_state_ids_for_event(
                         batch.events[-1].event_id, state_filter=state_filter
                     )
 
-                    state_ids = yield self.store.get_state_ids_for_event(
+                    state_ids = yield self.state_store.get_state_ids_for_event(
                         batch.events[0].event_id, state_filter=state_filter
                     )
 
@@ -781,7 +783,7 @@ class SyncHandler(object):
                 )
             elif batch.limited:
                 if batch:
-                    state_at_timeline_start = yield self.store.get_state_ids_for_event(
+                    state_at_timeline_start = yield self.state_store.get_state_ids_for_event(
                         batch.events[0].event_id, state_filter=state_filter
                     )
                 else:
@@ -810,7 +812,7 @@ class SyncHandler(object):
                 )
 
                 if batch:
-                    current_state_ids = yield self.store.get_state_ids_for_event(
+                    current_state_ids = yield self.state_store.get_state_ids_for_event(
                         batch.events[-1].event_id, state_filter=state_filter
                     )
                 else:
@@ -841,7 +843,7 @@ class SyncHandler(object):
                         # So we fish out all the member events corresponding to the
                         # timeline here, and then dedupe any redundant ones below.
 
-                        state_ids = yield self.store.get_state_ids_for_event(
+                        state_ids = yield self.state_store.get_state_ids_for_event(
                             batch.events[0].event_id,
                             # we only want members!
                             state_filter=StateFilter.from_types(
@@ -1204,10 +1206,11 @@ class SyncHandler(object):
         since_token = sync_result_builder.since_token
 
         if since_token and not sync_result_builder.full_state:
-            account_data, account_data_by_room = (
-                yield self.store.get_updated_account_data_for_user(
-                    user_id, since_token.account_data_key
-                )
+            (
+                account_data,
+                account_data_by_room,
+            ) = yield self.store.get_updated_account_data_for_user(
+                user_id, since_token.account_data_key
             )
 
             push_rules_changed = yield self.store.have_push_rules_changed_for_user(
@@ -1219,9 +1222,10 @@ class SyncHandler(object):
                     sync_config.user
                 )
         else:
-            account_data, account_data_by_room = (
-                yield self.store.get_account_data_for_user(sync_config.user.to_string())
-            )
+            (
+                account_data,
+                account_data_by_room,
+            ) = yield self.store.get_account_data_for_user(sync_config.user.to_string())
 
             account_data["m.push_rules"] = yield self.push_rules_for_user(
                 sync_config.user
diff --git a/synapse/handlers/ui_auth/checkers.py b/synapse/handlers/ui_auth/checkers.py
index 29aa1e5aaf..8363d887a9 100644
--- a/synapse/handlers/ui_auth/checkers.py
+++ b/synapse/handlers/ui_auth/checkers.py
@@ -81,7 +81,7 @@ class RecaptchaAuthChecker(UserInteractiveAuthChecker):
     def __init__(self, hs):
         super().__init__(hs)
         self._enabled = bool(hs.config.recaptcha_private_key)
-        self._http_client = hs.get_simple_http_client()
+        self._http_client = hs.get_proxied_http_client()
         self._url = hs.config.recaptcha_siteverify_api
         self._secret = hs.config.recaptcha_private_key
 
diff --git a/synapse/http/client.py b/synapse/http/client.py
index cdf828a4ff..d4c285445e 100644
--- a/synapse/http/client.py
+++ b/synapse/http/client.py
@@ -45,6 +45,7 @@ from synapse.http import (
     cancelled_to_request_timed_out_error,
     redact_uri,
 )
+from synapse.http.proxyagent import ProxyAgent
 from synapse.logging.context import make_deferred_yieldable
 from synapse.logging.opentracing import set_tag, start_active_span, tags
 from synapse.util.async_helpers import timeout_deferred
@@ -183,7 +184,15 @@ class SimpleHttpClient(object):
     using HTTP in Matrix
     """
 
-    def __init__(self, hs, treq_args={}, ip_whitelist=None, ip_blacklist=None):
+    def __init__(
+        self,
+        hs,
+        treq_args={},
+        ip_whitelist=None,
+        ip_blacklist=None,
+        http_proxy=None,
+        https_proxy=None,
+    ):
         """
         Args:
             hs (synapse.server.HomeServer)
@@ -192,6 +201,8 @@ class SimpleHttpClient(object):
                 we may not request.
             ip_whitelist (netaddr.IPSet): The whitelisted IP addresses, that we can
                request if it were otherwise caught in a blacklist.
+            http_proxy (bytes): proxy server to use for http connections. host[:port]
+            https_proxy (bytes): proxy server to use for https connections. host[:port]
         """
         self.hs = hs
 
@@ -236,11 +247,13 @@ class SimpleHttpClient(object):
         # The default context factory in Twisted 14.0.0 (which we require) is
         # BrowserLikePolicyForHTTPS which will do regular cert validation
         # 'like a browser'
-        self.agent = Agent(
+        self.agent = ProxyAgent(
             self.reactor,
             connectTimeout=15,
             contextFactory=self.hs.get_http_client_context_factory(),
             pool=pool,
+            http_proxy=http_proxy,
+            https_proxy=https_proxy,
         )
 
         if self._ip_blacklist:
@@ -535,7 +548,7 @@ class SimpleHttpClient(object):
             b"Content-Length" in resp_headers
             and int(resp_headers[b"Content-Length"][0]) > max_size
         ):
-            logger.warn("Requested URL is too large > %r bytes" % (self.max_size,))
+            logger.warning("Requested URL is too large > %r bytes" % (self.max_size,))
             raise SynapseError(
                 502,
                 "Requested file is too large > %r bytes" % (self.max_size,),
@@ -543,7 +556,7 @@ class SimpleHttpClient(object):
             )
 
         if response.code > 299:
-            logger.warn("Got %d when downloading %s" % (response.code, url))
+            logger.warning("Got %d when downloading %s" % (response.code, url))
             raise SynapseError(502, "Got error %d" % (response.code,), Codes.UNKNOWN)
 
         # TODO: if our Content-Type is HTML or something, just read the first
diff --git a/synapse/http/connectproxyclient.py b/synapse/http/connectproxyclient.py
new file mode 100644
index 0000000000..be7b2ceb8e
--- /dev/null
+++ b/synapse/http/connectproxyclient.py
@@ -0,0 +1,195 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 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 logging
+
+from zope.interface import implementer
+
+from twisted.internet import defer, protocol
+from twisted.internet.error import ConnectError
+from twisted.internet.interfaces import IStreamClientEndpoint
+from twisted.internet.protocol import connectionDone
+from twisted.web import http
+
+logger = logging.getLogger(__name__)
+
+
+class ProxyConnectError(ConnectError):
+    pass
+
+
+@implementer(IStreamClientEndpoint)
+class HTTPConnectProxyEndpoint(object):
+    """An Endpoint implementation which will send a CONNECT request to an http proxy
+
+    Wraps an existing HostnameEndpoint for the proxy.
+
+    When we get the connect() request from the connection pool (via the TLS wrapper),
+    we'll first connect to the proxy endpoint with a ProtocolFactory which will make the
+    CONNECT request. Once that completes, we invoke the protocolFactory which was passed
+    in.
+
+    Args:
+        reactor: the Twisted reactor to use for the connection
+        proxy_endpoint (IStreamClientEndpoint): the endpoint to use to connect to the
+            proxy
+        host (bytes): hostname that we want to CONNECT to
+        port (int): port that we want to connect to
+    """
+
+    def __init__(self, reactor, proxy_endpoint, host, port):
+        self._reactor = reactor
+        self._proxy_endpoint = proxy_endpoint
+        self._host = host
+        self._port = port
+
+    def __repr__(self):
+        return "<HTTPConnectProxyEndpoint %s>" % (self._proxy_endpoint,)
+
+    def connect(self, protocolFactory):
+        f = HTTPProxiedClientFactory(self._host, self._port, protocolFactory)
+        d = self._proxy_endpoint.connect(f)
+        # once the tcp socket connects successfully, we need to wait for the
+        # CONNECT to complete.
+        d.addCallback(lambda conn: f.on_connection)
+        return d
+
+
+class HTTPProxiedClientFactory(protocol.ClientFactory):
+    """ClientFactory wrapper that triggers an HTTP proxy CONNECT on connect.
+
+    Once the CONNECT completes, invokes the original ClientFactory to build the
+    HTTP Protocol object and run the rest of the connection.
+
+    Args:
+        dst_host (bytes): hostname that we want to CONNECT to
+        dst_port (int): port that we want to connect to
+        wrapped_factory (protocol.ClientFactory): The original Factory
+    """
+
+    def __init__(self, dst_host, dst_port, wrapped_factory):
+        self.dst_host = dst_host
+        self.dst_port = dst_port
+        self.wrapped_factory = wrapped_factory
+        self.on_connection = defer.Deferred()
+
+    def startedConnecting(self, connector):
+        return self.wrapped_factory.startedConnecting(connector)
+
+    def buildProtocol(self, addr):
+        wrapped_protocol = self.wrapped_factory.buildProtocol(addr)
+
+        return HTTPConnectProtocol(
+            self.dst_host, self.dst_port, wrapped_protocol, self.on_connection
+        )
+
+    def clientConnectionFailed(self, connector, reason):
+        logger.debug("Connection to proxy failed: %s", reason)
+        if not self.on_connection.called:
+            self.on_connection.errback(reason)
+        return self.wrapped_factory.clientConnectionFailed(connector, reason)
+
+    def clientConnectionLost(self, connector, reason):
+        logger.debug("Connection to proxy lost: %s", reason)
+        if not self.on_connection.called:
+            self.on_connection.errback(reason)
+        return self.wrapped_factory.clientConnectionLost(connector, reason)
+
+
+class HTTPConnectProtocol(protocol.Protocol):
+    """Protocol that wraps an existing Protocol to do a CONNECT handshake at connect
+
+    Args:
+        host (bytes): The original HTTP(s) hostname or IPv4 or IPv6 address literal
+            to put in the CONNECT request
+
+        port (int): The original HTTP(s) port to put in the CONNECT request
+
+        wrapped_protocol (interfaces.IProtocol): the original protocol (probably
+            HTTPChannel or TLSMemoryBIOProtocol, but could be anything really)
+
+        connected_deferred (Deferred): a Deferred which will be callbacked with
+            wrapped_protocol when the CONNECT completes
+    """
+
+    def __init__(self, host, port, wrapped_protocol, connected_deferred):
+        self.host = host
+        self.port = port
+        self.wrapped_protocol = wrapped_protocol
+        self.connected_deferred = connected_deferred
+        self.http_setup_client = HTTPConnectSetupClient(self.host, self.port)
+        self.http_setup_client.on_connected.addCallback(self.proxyConnected)
+
+    def connectionMade(self):
+        self.http_setup_client.makeConnection(self.transport)
+
+    def connectionLost(self, reason=connectionDone):
+        if self.wrapped_protocol.connected:
+            self.wrapped_protocol.connectionLost(reason)
+
+        self.http_setup_client.connectionLost(reason)
+
+        if not self.connected_deferred.called:
+            self.connected_deferred.errback(reason)
+
+    def proxyConnected(self, _):
+        self.wrapped_protocol.makeConnection(self.transport)
+
+        self.connected_deferred.callback(self.wrapped_protocol)
+
+        # Get any pending data from the http buf and forward it to the original protocol
+        buf = self.http_setup_client.clearLineBuffer()
+        if buf:
+            self.wrapped_protocol.dataReceived(buf)
+
+    def dataReceived(self, data):
+        # if we've set up the HTTP protocol, we can send the data there
+        if self.wrapped_protocol.connected:
+            return self.wrapped_protocol.dataReceived(data)
+
+        # otherwise, we must still be setting up the connection: send the data to the
+        # setup client
+        return self.http_setup_client.dataReceived(data)
+
+
+class HTTPConnectSetupClient(http.HTTPClient):
+    """HTTPClient protocol to send a CONNECT message for proxies and read the response.
+
+    Args:
+        host (bytes): The hostname to send in the CONNECT message
+        port (int): The port to send in the CONNECT message
+    """
+
+    def __init__(self, host, port):
+        self.host = host
+        self.port = port
+        self.on_connected = defer.Deferred()
+
+    def connectionMade(self):
+        logger.debug("Connected to proxy, sending CONNECT")
+        self.sendCommand(b"CONNECT", b"%s:%d" % (self.host, self.port))
+        self.endHeaders()
+
+    def handleStatus(self, version, status, message):
+        logger.debug("Got Status: %s %s %s", status, message, version)
+        if status != b"200":
+            raise ProxyConnectError("Unexpected status on CONNECT: %s" % status)
+
+    def handleEndHeaders(self):
+        logger.debug("End Headers")
+        self.on_connected.callback(None)
+
+    def handleResponse(self, body):
+        pass
diff --git a/synapse/http/federation/srv_resolver.py b/synapse/http/federation/srv_resolver.py
index 3fe4ffb9e5..021b233a7d 100644
--- a/synapse/http/federation/srv_resolver.py
+++ b/synapse/http/federation/srv_resolver.py
@@ -148,7 +148,7 @@ class SrvResolver(object):
             # Try something in the cache, else rereaise
             cache_entry = self._cache.get(service_name, None)
             if cache_entry:
-                logger.warn(
+                logger.warning(
                     "Failed to resolve %r, falling back to cache. %r", service_name, e
                 )
                 return list(cache_entry)
diff --git a/synapse/http/matrixfederationclient.py b/synapse/http/matrixfederationclient.py
index 3f7c93ffcb..691380abda 100644
--- a/synapse/http/matrixfederationclient.py
+++ b/synapse/http/matrixfederationclient.py
@@ -149,7 +149,7 @@ def _handle_json_response(reactor, timeout_sec, request, response):
 
         body = yield make_deferred_yieldable(d)
     except Exception as e:
-        logger.warn(
+        logger.warning(
             "{%s} [%s] Error reading response: %s",
             request.txn_id,
             request.destination,
@@ -457,7 +457,7 @@ class MatrixFederationHttpClient(object):
                         except Exception as e:
                             # Eh, we're already going to raise an exception so lets
                             # ignore if this fails.
-                            logger.warn(
+                            logger.warning(
                                 "{%s} [%s] Failed to get error response: %s %s: %s",
                                 request.txn_id,
                                 request.destination,
@@ -478,7 +478,7 @@ class MatrixFederationHttpClient(object):
 
                     break
                 except RequestSendFailed as e:
-                    logger.warn(
+                    logger.warning(
                         "{%s} [%s] Request failed: %s %s: %s",
                         request.txn_id,
                         request.destination,
@@ -513,7 +513,7 @@ class MatrixFederationHttpClient(object):
                         raise
 
                 except Exception as e:
-                    logger.warn(
+                    logger.warning(
                         "{%s} [%s] Request failed: %s %s: %s",
                         request.txn_id,
                         request.destination,
@@ -889,7 +889,7 @@ class MatrixFederationHttpClient(object):
             d.addTimeout(self.default_timeout, self.reactor)
             length = yield make_deferred_yieldable(d)
         except Exception as e:
-            logger.warn(
+            logger.warning(
                 "{%s} [%s] Error reading response: %s",
                 request.txn_id,
                 request.destination,
diff --git a/synapse/http/proxyagent.py b/synapse/http/proxyagent.py
new file mode 100644
index 0000000000..332da02a8d
--- /dev/null
+++ b/synapse/http/proxyagent.py
@@ -0,0 +1,195 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 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 logging
+import re
+
+from zope.interface import implementer
+
+from twisted.internet import defer
+from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS
+from twisted.python.failure import Failure
+from twisted.web.client import URI, BrowserLikePolicyForHTTPS, _AgentBase
+from twisted.web.error import SchemeNotSupported
+from twisted.web.iweb import IAgent
+
+from synapse.http.connectproxyclient import HTTPConnectProxyEndpoint
+
+logger = logging.getLogger(__name__)
+
+_VALID_URI = re.compile(br"\A[\x21-\x7e]+\Z")
+
+
+@implementer(IAgent)
+class ProxyAgent(_AgentBase):
+    """An Agent implementation which will use an HTTP proxy if one was requested
+
+    Args:
+        reactor: twisted reactor to place outgoing
+            connections.
+
+        contextFactory (IPolicyForHTTPS): A factory for TLS contexts, to control the
+            verification parameters of OpenSSL.  The default is to use a
+            `BrowserLikePolicyForHTTPS`, so unless you have special
+            requirements you can leave this as-is.
+
+        connectTimeout (float): The amount of time that this Agent will wait
+            for the peer to accept a connection.
+
+        bindAddress (bytes): The local address for client sockets to bind to.
+
+        pool (HTTPConnectionPool|None): connection pool to be used. If None, a
+            non-persistent pool instance will be created.
+    """
+
+    def __init__(
+        self,
+        reactor,
+        contextFactory=BrowserLikePolicyForHTTPS(),
+        connectTimeout=None,
+        bindAddress=None,
+        pool=None,
+        http_proxy=None,
+        https_proxy=None,
+    ):
+        _AgentBase.__init__(self, reactor, pool)
+
+        self._endpoint_kwargs = {}
+        if connectTimeout is not None:
+            self._endpoint_kwargs["timeout"] = connectTimeout
+        if bindAddress is not None:
+            self._endpoint_kwargs["bindAddress"] = bindAddress
+
+        self.http_proxy_endpoint = _http_proxy_endpoint(
+            http_proxy, reactor, **self._endpoint_kwargs
+        )
+
+        self.https_proxy_endpoint = _http_proxy_endpoint(
+            https_proxy, reactor, **self._endpoint_kwargs
+        )
+
+        self._policy_for_https = contextFactory
+        self._reactor = reactor
+
+    def request(self, method, uri, headers=None, bodyProducer=None):
+        """
+        Issue a request to the server indicated by the given uri.
+
+        Supports `http` and `https` schemes.
+
+        An existing connection from the connection pool may be used or a new one may be
+        created.
+
+        See also: twisted.web.iweb.IAgent.request
+
+        Args:
+            method (bytes): The request method to use, such as `GET`, `POST`, etc
+
+            uri (bytes): The location of the resource to request.
+
+            headers (Headers|None): Extra headers to send with the request
+
+            bodyProducer (IBodyProducer|None): An object which can generate bytes to
+                make up the body of this request (for example, the properly encoded
+                contents of a file for a file upload). Or, None if the request is to
+                have no body.
+
+        Returns:
+            Deferred[IResponse]: completes when the header of the response has
+                 been received (regardless of the response status code).
+        """
+        uri = uri.strip()
+        if not _VALID_URI.match(uri):
+            raise ValueError("Invalid URI {!r}".format(uri))
+
+        parsed_uri = URI.fromBytes(uri)
+        pool_key = (parsed_uri.scheme, parsed_uri.host, parsed_uri.port)
+        request_path = parsed_uri.originForm
+
+        if parsed_uri.scheme == b"http" and self.http_proxy_endpoint:
+            # Cache *all* connections under the same key, since we are only
+            # connecting to a single destination, the proxy:
+            pool_key = ("http-proxy", self.http_proxy_endpoint)
+            endpoint = self.http_proxy_endpoint
+            request_path = uri
+        elif parsed_uri.scheme == b"https" and self.https_proxy_endpoint:
+            endpoint = HTTPConnectProxyEndpoint(
+                self._reactor,
+                self.https_proxy_endpoint,
+                parsed_uri.host,
+                parsed_uri.port,
+            )
+        else:
+            # not using a proxy
+            endpoint = HostnameEndpoint(
+                self._reactor, parsed_uri.host, parsed_uri.port, **self._endpoint_kwargs
+            )
+
+        logger.debug("Requesting %s via %s", uri, endpoint)
+
+        if parsed_uri.scheme == b"https":
+            tls_connection_creator = self._policy_for_https.creatorForNetloc(
+                parsed_uri.host, parsed_uri.port
+            )
+            endpoint = wrapClientTLS(tls_connection_creator, endpoint)
+        elif parsed_uri.scheme == b"http":
+            pass
+        else:
+            return defer.fail(
+                Failure(
+                    SchemeNotSupported("Unsupported scheme: %r" % (parsed_uri.scheme,))
+                )
+            )
+
+        return self._requestWithEndpoint(
+            pool_key, endpoint, method, parsed_uri, headers, bodyProducer, request_path
+        )
+
+
+def _http_proxy_endpoint(proxy, reactor, **kwargs):
+    """Parses an http proxy setting and returns an endpoint for the proxy
+
+    Args:
+        proxy (bytes|None):  the proxy setting
+        reactor: reactor to be used to connect to the proxy
+        kwargs: other args to be passed to HostnameEndpoint
+
+    Returns:
+        interfaces.IStreamClientEndpoint|None: endpoint to use to connect to the proxy,
+            or None
+    """
+    if proxy is None:
+        return None
+
+    # currently we only support hostname:port. Some apps also support
+    # protocol://<host>[:port], which allows a way of requiring a TLS connection to the
+    # proxy.
+
+    host, port = parse_host_port(proxy, default_port=1080)
+    return HostnameEndpoint(reactor, host, port, **kwargs)
+
+
+def parse_host_port(hostport, default_port=None):
+    # could have sworn we had one of these somewhere else...
+    if b":" in hostport:
+        host, port = hostport.rsplit(b":", 1)
+        try:
+            port = int(port)
+            return host, port
+        except ValueError:
+            # the thing after the : wasn't a valid port; presumably this is an
+            # IPv6 address.
+            pass
+
+    return hostport, default_port
diff --git a/synapse/http/request_metrics.py b/synapse/http/request_metrics.py
index 46af27c8f6..58f9cc61c8 100644
--- a/synapse/http/request_metrics.py
+++ b/synapse/http/request_metrics.py
@@ -170,7 +170,7 @@ class RequestMetrics(object):
             tag = context.tag
 
             if context != self.start_context:
-                logger.warn(
+                logger.warning(
                     "Context have unexpectedly changed %r, %r",
                     context,
                     self.start_context,
diff --git a/synapse/http/server.py b/synapse/http/server.py
index 2ccb210fd6..943d12c907 100644
--- a/synapse/http/server.py
+++ b/synapse/http/server.py
@@ -454,7 +454,7 @@ def respond_with_json(
     # the Deferred fires, but since the flag is RIGHT THERE it seems like
     # a waste.
     if request._disconnected:
-        logger.warn(
+        logger.warning(
             "Not sending response to request %s, already disconnected.", request
         )
         return
diff --git a/synapse/http/servlet.py b/synapse/http/servlet.py
index 274c1a6a87..e9a5e46ced 100644
--- a/synapse/http/servlet.py
+++ b/synapse/http/servlet.py
@@ -219,13 +219,13 @@ def parse_json_value_from_request(request, allow_empty_body=False):
     try:
         content_unicode = content_bytes.decode("utf8")
     except UnicodeDecodeError:
-        logger.warn("Unable to decode UTF-8")
+        logger.warning("Unable to decode UTF-8")
         raise SynapseError(400, "Content not JSON.", errcode=Codes.NOT_JSON)
 
     try:
         content = json.loads(content_unicode)
     except Exception as e:
-        logger.warn("Unable to parse JSON: %s", e)
+        logger.warning("Unable to parse JSON: %s", e)
         raise SynapseError(400, "Content not JSON.", errcode=Codes.NOT_JSON)
 
     return content
diff --git a/synapse/http/site.py b/synapse/http/site.py
index df5274c177..ff8184a3d0 100644
--- a/synapse/http/site.py
+++ b/synapse/http/site.py
@@ -199,7 +199,7 @@ class SynapseRequest(Request):
         # It's useful to log it here so that we can get an idea of when
         # the client disconnects.
         with PreserveLoggingContext(self.logcontext):
-            logger.warn(
+            logger.warning(
                 "Error processing request %r: %s %s", self, reason.type, reason.value
             )
 
@@ -305,7 +305,7 @@ class SynapseRequest(Request):
         try:
             self.request_metrics.stop(self.finish_time, self.code, self.sentLength)
         except Exception as e:
-            logger.warn("Failed to stop metrics: %r", e)
+            logger.warning("Failed to stop metrics: %r", e)
 
 
 class XForwardedForRequest(SynapseRequest):
diff --git a/synapse/logging/_structured.py b/synapse/logging/_structured.py
index 3220e985a9..334ddaf39a 100644
--- a/synapse/logging/_structured.py
+++ b/synapse/logging/_structured.py
@@ -185,7 +185,7 @@ DEFAULT_LOGGERS = {"synapse": {"level": "INFO"}}
 
 
 def parse_drain_configs(
-    drains: dict
+    drains: dict,
 ) -> typing.Generator[DrainConfiguration, None, None]:
     """
     Parse the drain configurations.
diff --git a/synapse/logging/context.py b/synapse/logging/context.py
index 370000e377..2c1fb9ddac 100644
--- a/synapse/logging/context.py
+++ b/synapse/logging/context.py
@@ -294,7 +294,7 @@ class LoggingContext(object):
         """Enters this logging context into thread local storage"""
         old_context = self.set_current_context(self)
         if self.previous_context != old_context:
-            logger.warn(
+            logger.warning(
                 "Expected previous context %r, found %r",
                 self.previous_context,
                 old_context,
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 4e091314e6..af161a81d7 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -159,6 +159,7 @@ class Notifier(object):
         self.room_to_user_streams = {}
 
         self.hs = hs
+        self.storage = hs.get_storage()
         self.event_sources = hs.get_event_sources()
         self.store = hs.get_datastore()
         self.pending_new_room_events = []
@@ -425,7 +426,10 @@ class Notifier(object):
 
                 if name == "room":
                     new_events = yield filter_events_for_client(
-                        self.store, user.to_string(), new_events, is_peeking=is_peeking
+                        self.storage,
+                        user.to_string(),
+                        new_events,
+                        is_peeking=is_peeking,
                     )
                 elif name == "presence":
                     now = self.clock.time_msec()
diff --git a/synapse/push/bulk_push_rule_evaluator.py b/synapse/push/bulk_push_rule_evaluator.py
index 22491f3700..1ba7bcd4d8 100644
--- a/synapse/push/bulk_push_rule_evaluator.py
+++ b/synapse/push/bulk_push_rule_evaluator.py
@@ -79,7 +79,7 @@ class BulkPushRuleEvaluator(object):
             dict of user_id -> push_rules
         """
         room_id = event.room_id
-        rules_for_room = self._get_rules_for_room(room_id)
+        rules_for_room = yield self._get_rules_for_room(room_id)
 
         rules_by_user = yield rules_for_room.get_rules(event, context)
 
@@ -149,9 +149,10 @@ class BulkPushRuleEvaluator(object):
 
         room_members = yield self.store.get_joined_users_from_context(event, context)
 
-        (power_levels, sender_power_level) = (
-            yield self._get_power_levels_and_sender_level(event, context)
-        )
+        (
+            power_levels,
+            sender_power_level,
+        ) = yield self._get_power_levels_and_sender_level(event, context)
 
         evaluator = PushRuleEvaluatorForEvent(
             event, len(room_members), sender_power_level, power_levels
diff --git a/synapse/push/emailpusher.py b/synapse/push/emailpusher.py
index 42e5b0c0a5..8c818a86bf 100644
--- a/synapse/push/emailpusher.py
+++ b/synapse/push/emailpusher.py
@@ -234,14 +234,12 @@ class EmailPusher(object):
             return
 
         self.last_stream_ordering = last_stream_ordering
-        pusher_still_exists = (
-            yield self.store.update_pusher_last_stream_ordering_and_success(
-                self.app_id,
-                self.email,
-                self.user_id,
-                last_stream_ordering,
-                self.clock.time_msec(),
-            )
+        pusher_still_exists = yield self.store.update_pusher_last_stream_ordering_and_success(
+            self.app_id,
+            self.email,
+            self.user_id,
+            last_stream_ordering,
+            self.clock.time_msec(),
         )
         if not pusher_still_exists:
             # The pusher has been deleted while we were processing, so
diff --git a/synapse/push/httppusher.py b/synapse/push/httppusher.py
index 6299587808..e994037be6 100644
--- a/synapse/push/httppusher.py
+++ b/synapse/push/httppusher.py
@@ -64,6 +64,7 @@ class HttpPusher(object):
     def __init__(self, hs, pusherdict):
         self.hs = hs
         self.store = self.hs.get_datastore()
+        self.storage = self.hs.get_storage()
         self.clock = self.hs.get_clock()
         self.state_handler = self.hs.get_state_handler()
         self.user_id = pusherdict["user_name"]
@@ -102,7 +103,7 @@ class HttpPusher(object):
         if "url" not in self.data:
             raise PusherConfigException("'url' required in data for HTTP pusher")
         self.url = self.data["url"]
-        self.http_client = hs.get_simple_http_client()
+        self.http_client = hs.get_proxied_http_client()
         self.data_minus_url = {}
         self.data_minus_url.update(self.data)
         del self.data_minus_url["url"]
@@ -210,14 +211,12 @@ class HttpPusher(object):
                 http_push_processed_counter.inc()
                 self.backoff_delay = HttpPusher.INITIAL_BACKOFF_SEC
                 self.last_stream_ordering = push_action["stream_ordering"]
-                pusher_still_exists = (
-                    yield self.store.update_pusher_last_stream_ordering_and_success(
-                        self.app_id,
-                        self.pushkey,
-                        self.user_id,
-                        self.last_stream_ordering,
-                        self.clock.time_msec(),
-                    )
+                pusher_still_exists = yield self.store.update_pusher_last_stream_ordering_and_success(
+                    self.app_id,
+                    self.pushkey,
+                    self.user_id,
+                    self.last_stream_ordering,
+                    self.clock.time_msec(),
                 )
                 if not pusher_still_exists:
                     # The pusher has been deleted while we were processing, so
@@ -246,7 +245,7 @@ class HttpPusher(object):
                     # we really only give up so that if the URL gets
                     # fixed, we don't suddenly deliver a load
                     # of old notifications.
-                    logger.warn(
+                    logger.warning(
                         "Giving up on a notification to user %s, " "pushkey %s",
                         self.user_id,
                         self.pushkey,
@@ -299,7 +298,7 @@ class HttpPusher(object):
                 if pk != self.pushkey:
                     # for sanity, we only remove the pushkey if it
                     # was the one we actually sent...
-                    logger.warn(
+                    logger.warning(
                         ("Ignoring rejected pushkey %s because we" " didn't send it"),
                         pk,
                     )
@@ -329,7 +328,7 @@ class HttpPusher(object):
             return d
 
         ctx = yield push_tools.get_context_for_event(
-            self.store, self.state_handler, event, self.user_id
+            self.storage, self.state_handler, event, self.user_id
         )
 
         d = {
diff --git a/synapse/push/mailer.py b/synapse/push/mailer.py
index 5b16ab4ae8..1d15a06a58 100644
--- a/synapse/push/mailer.py
+++ b/synapse/push/mailer.py
@@ -119,6 +119,7 @@ class Mailer(object):
         self.store = self.hs.get_datastore()
         self.macaroon_gen = self.hs.get_macaroon_generator()
         self.state_handler = self.hs.get_state_handler()
+        self.storage = hs.get_storage()
         self.app_name = app_name
 
         logger.info("Created Mailer for app_name %s" % app_name)
@@ -389,7 +390,7 @@ class Mailer(object):
         }
 
         the_events = yield filter_events_for_client(
-            self.store, user_id, results["events_before"]
+            self.storage, user_id, results["events_before"]
         )
         the_events.append(notif_event)
 
diff --git a/synapse/push/push_rule_evaluator.py b/synapse/push/push_rule_evaluator.py
index 5ed9147de4..b1587183a8 100644
--- a/synapse/push/push_rule_evaluator.py
+++ b/synapse/push/push_rule_evaluator.py
@@ -117,7 +117,7 @@ class PushRuleEvaluatorForEvent(object):
                 pattern = UserID.from_string(user_id).localpart
 
         if not pattern:
-            logger.warn("event_match condition with no pattern")
+            logger.warning("event_match condition with no pattern")
             return False
 
         # XXX: optimisation: cache our pattern regexps
@@ -173,7 +173,7 @@ def _glob_matches(glob, value, word_boundary=False):
             regex_cache[(glob, word_boundary)] = r
         return r.search(value)
     except re.error:
-        logger.warn("Failed to parse glob to regex: %r", glob)
+        logger.warning("Failed to parse glob to regex: %r", glob)
         return False
 
 
diff --git a/synapse/push/push_tools.py b/synapse/push/push_tools.py
index a54051a726..de5c101a58 100644
--- a/synapse/push/push_tools.py
+++ b/synapse/push/push_tools.py
@@ -16,6 +16,7 @@
 from twisted.internet import defer
 
 from synapse.push.presentable_names import calculate_room_name, name_from_member_event
+from synapse.storage import Storage
 
 
 @defer.inlineCallbacks
@@ -43,22 +44,22 @@ def get_badge_count(store, user_id):
 
 
 @defer.inlineCallbacks
-def get_context_for_event(store, state_handler, ev, user_id):
+def get_context_for_event(storage: Storage, state_handler, ev, user_id):
     ctx = {}
 
-    room_state_ids = yield store.get_state_ids_for_event(ev.event_id)
+    room_state_ids = yield storage.state.get_state_ids_for_event(ev.event_id)
 
     # we no longer bother setting room_alias, and make room_name the
     # human-readable name instead, be that m.room.name, an alias or
     # a list of people in the room
     name = yield calculate_room_name(
-        store, room_state_ids, user_id, fallback_to_single_member=False
+        storage.main, room_state_ids, user_id, fallback_to_single_member=False
     )
     if name:
         ctx["name"] = name
 
     sender_state_event_id = room_state_ids[("m.room.member", ev.sender)]
-    sender_state_event = yield store.get_event(sender_state_event_id)
+    sender_state_event = yield storage.main.get_event(sender_state_event_id)
     ctx["sender_display_name"] = name_from_member_event(sender_state_event)
 
     return ctx
diff --git a/synapse/push/pusherpool.py b/synapse/push/pusherpool.py
index 08e840fdc2..0f6992202d 100644
--- a/synapse/push/pusherpool.py
+++ b/synapse/push/pusherpool.py
@@ -103,9 +103,7 @@ class PusherPool:
         # create the pusher setting last_stream_ordering to the current maximum
         # stream ordering in event_push_actions, so it will process
         # pushes from this point onwards.
-        last_stream_ordering = (
-            yield self.store.get_latest_push_action_stream_ordering()
-        )
+        last_stream_ordering = yield self.store.get_latest_push_action_stream_ordering()
 
         yield self.store.add_pusher(
             user_id=user_id,
diff --git a/synapse/python_dependencies.py b/synapse/python_dependencies.py
index aa7da1c543..5871feaafd 100644
--- a/synapse/python_dependencies.py
+++ b/synapse/python_dependencies.py
@@ -61,7 +61,6 @@ REQUIREMENTS = [
     "bcrypt>=3.1.0",
     "pillow>=4.3.0",
     "sortedcontainers>=1.4.4",
-    "psutil>=2.0.0",
     "pymacaroons>=0.13.0",
     "msgpack>=0.5.2",
     "phonenumbers>=8.2.0",
diff --git a/synapse/replication/http/_base.py b/synapse/replication/http/_base.py
index 03560c1f0e..c8056b0c0c 100644
--- a/synapse/replication/http/_base.py
+++ b/synapse/replication/http/_base.py
@@ -110,14 +110,14 @@ class ReplicationEndpoint(object):
         return {}
 
     @abc.abstractmethod
-    def _handle_request(self, request, **kwargs):
+    async def _handle_request(self, request, **kwargs):
         """Handle incoming request.
 
         This is called with the request object and PATH_ARGS.
 
         Returns:
-            Deferred[dict]: A JSON serialisable dict to be used as response
-            body of request.
+            tuple[int, dict]: HTTP status code and a JSON serialisable dict
+            to be used as response body of request.
         """
         pass
 
@@ -180,7 +180,7 @@ class ReplicationEndpoint(object):
                         if e.code != 504 or not cls.RETRY_ON_TIMEOUT:
                             raise
 
-                    logger.warn("%s request timed out", cls.NAME)
+                    logger.warning("%s request timed out", cls.NAME)
 
                     # If we timed out we probably don't need to worry about backing
                     # off too much, but lets just wait a little anyway.
diff --git a/synapse/replication/http/federation.py b/synapse/replication/http/federation.py
index 2f16955954..9af4e7e173 100644
--- a/synapse/replication/http/federation.py
+++ b/synapse/replication/http/federation.py
@@ -82,8 +82,7 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
 
         return payload
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request):
+    async def _handle_request(self, request):
         with Measure(self.clock, "repl_fed_send_events_parse"):
             content = parse_json_object_from_request(request)
 
@@ -101,15 +100,13 @@ class ReplicationFederationSendEventsRestServlet(ReplicationEndpoint):
                 EventType = event_type_from_format_version(format_ver)
                 event = EventType(event_dict, internal_metadata, rejected_reason)
 
-                context = yield EventContext.deserialize(
-                    self.store, event_payload["context"]
-                )
+                context = EventContext.deserialize(self.store, event_payload["context"])
 
                 event_and_contexts.append((event, context))
 
         logger.info("Got %d events from federation", len(event_and_contexts))
 
-        yield self.federation_handler.persist_events_and_notify(
+        await self.federation_handler.persist_events_and_notify(
             event_and_contexts, backfilled
         )
 
@@ -144,8 +141,7 @@ class ReplicationFederationSendEduRestServlet(ReplicationEndpoint):
     def _serialize_payload(edu_type, origin, content):
         return {"origin": origin, "content": content}
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, edu_type):
+    async def _handle_request(self, request, edu_type):
         with Measure(self.clock, "repl_fed_send_edu_parse"):
             content = parse_json_object_from_request(request)
 
@@ -154,7 +150,7 @@ class ReplicationFederationSendEduRestServlet(ReplicationEndpoint):
 
         logger.info("Got %r edu from %s", edu_type, origin)
 
-        result = yield self.registry.on_edu(edu_type, origin, edu_content)
+        result = await self.registry.on_edu(edu_type, origin, edu_content)
 
         return 200, result
 
@@ -193,8 +189,7 @@ class ReplicationGetQueryRestServlet(ReplicationEndpoint):
         """
         return {"args": args}
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, query_type):
+    async def _handle_request(self, request, query_type):
         with Measure(self.clock, "repl_fed_query_parse"):
             content = parse_json_object_from_request(request)
 
@@ -202,7 +197,7 @@ class ReplicationGetQueryRestServlet(ReplicationEndpoint):
 
         logger.info("Got %r query", query_type)
 
-        result = yield self.registry.on_query(query_type, args)
+        result = await self.registry.on_query(query_type, args)
 
         return 200, result
 
@@ -234,9 +229,8 @@ class ReplicationCleanRoomRestServlet(ReplicationEndpoint):
         """
         return {}
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, room_id):
-        yield self.store.clean_room_for_join(room_id)
+    async def _handle_request(self, request, room_id):
+        await self.store.clean_room_for_join(room_id)
 
         return 200, {}
 
diff --git a/synapse/replication/http/login.py b/synapse/replication/http/login.py
index 786f5232b2..798b9d3af5 100644
--- a/synapse/replication/http/login.py
+++ b/synapse/replication/http/login.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
 
@@ -52,15 +50,14 @@ class RegisterDeviceReplicationServlet(ReplicationEndpoint):
             "is_guest": is_guest,
         }
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, user_id):
+    async def _handle_request(self, request, user_id):
         content = parse_json_object_from_request(request)
 
         device_id = content["device_id"]
         initial_display_name = content["initial_display_name"]
         is_guest = content["is_guest"]
 
-        device_id, access_token = yield self.registration_handler.register_device(
+        device_id, access_token = await self.registration_handler.register_device(
             user_id, device_id, initial_display_name, is_guest
         )
 
diff --git a/synapse/replication/http/membership.py b/synapse/replication/http/membership.py
index b9ce3477ad..cc1f249740 100644
--- a/synapse/replication/http/membership.py
+++ b/synapse/replication/http/membership.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
 from synapse.types import Requester, UserID
@@ -65,8 +63,7 @@ class ReplicationRemoteJoinRestServlet(ReplicationEndpoint):
             "content": content,
         }
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, room_id, user_id):
+    async def _handle_request(self, request, room_id, user_id):
         content = parse_json_object_from_request(request)
 
         remote_room_hosts = content["remote_room_hosts"]
@@ -79,7 +76,7 @@ class ReplicationRemoteJoinRestServlet(ReplicationEndpoint):
 
         logger.info("remote_join: %s into room: %s", user_id, room_id)
 
-        yield self.federation_handler.do_invite_join(
+        await self.federation_handler.do_invite_join(
             remote_room_hosts, room_id, user_id, event_content
         )
 
@@ -123,8 +120,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
             "remote_room_hosts": remote_room_hosts,
         }
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, room_id, user_id):
+    async def _handle_request(self, request, room_id, user_id):
         content = parse_json_object_from_request(request)
 
         remote_room_hosts = content["remote_room_hosts"]
@@ -137,7 +133,7 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
         logger.info("remote_reject_invite: %s out of room: %s", user_id, room_id)
 
         try:
-            event = yield self.federation_handler.do_remotely_reject_invite(
+            event = await self.federation_handler.do_remotely_reject_invite(
                 remote_room_hosts, room_id, user_id
             )
             ret = event.get_pdu_json()
@@ -148,9 +144,9 @@ class ReplicationRemoteRejectInviteRestServlet(ReplicationEndpoint):
             # The 'except' clause is very broad, but we need to
             # capture everything from DNS failures upwards
             #
-            logger.warn("Failed to reject invite: %s", e)
+            logger.warning("Failed to reject invite: %s", e)
 
-            yield self.store.locally_reject_invite(user_id, room_id)
+            await self.store.locally_reject_invite(user_id, room_id)
             ret = {}
 
         return 200, ret
diff --git a/synapse/replication/http/register.py b/synapse/replication/http/register.py
index 38260256cf..915cfb9430 100644
--- a/synapse/replication/http/register.py
+++ b/synapse/replication/http/register.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.servlet import parse_json_object_from_request
 from synapse.replication.http._base import ReplicationEndpoint
 
@@ -74,11 +72,10 @@ class ReplicationRegisterServlet(ReplicationEndpoint):
             "address": address,
         }
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, user_id):
+    async def _handle_request(self, request, user_id):
         content = parse_json_object_from_request(request)
 
-        yield self.registration_handler.register_with_store(
+        await self.registration_handler.register_with_store(
             user_id=user_id,
             password_hash=content["password_hash"],
             was_guest=content["was_guest"],
@@ -117,14 +114,13 @@ class ReplicationPostRegisterActionsServlet(ReplicationEndpoint):
         """
         return {"auth_result": auth_result, "access_token": access_token}
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, user_id):
+    async def _handle_request(self, request, user_id):
         content = parse_json_object_from_request(request)
 
         auth_result = content["auth_result"]
         access_token = content["access_token"]
 
-        yield self.registration_handler.post_registration_actions(
+        await self.registration_handler.post_registration_actions(
             user_id=user_id, auth_result=auth_result, access_token=access_token
         )
 
diff --git a/synapse/replication/http/send_event.py b/synapse/replication/http/send_event.py
index adb9b2f7f4..9bafd60b14 100644
--- a/synapse/replication/http/send_event.py
+++ b/synapse/replication/http/send_event.py
@@ -87,8 +87,7 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
 
         return payload
 
-    @defer.inlineCallbacks
-    def _handle_request(self, request, event_id):
+    async def _handle_request(self, request, event_id):
         with Measure(self.clock, "repl_send_event_parse"):
             content = parse_json_object_from_request(request)
 
@@ -101,7 +100,7 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
             event = EventType(event_dict, internal_metadata, rejected_reason)
 
             requester = Requester.deserialize(self.store, content["requester"])
-            context = yield EventContext.deserialize(self.store, content["context"])
+            context = EventContext.deserialize(self.store, content["context"])
 
             ratelimit = content["ratelimit"]
             extra_users = [UserID.from_string(u) for u in content["extra_users"]]
@@ -113,7 +112,7 @@ class ReplicationSendEventRestServlet(ReplicationEndpoint):
             "Got event to send with ID: %s into room: %s", event.event_id, event.room_id
         )
 
-        yield self.event_creation_handler.persist_and_notify_client_event(
+        await self.event_creation_handler.persist_and_notify_client_event(
             requester, event, context, ratelimit=ratelimit, extra_users=extra_users
         )
 
diff --git a/synapse/replication/slave/storage/_base.py b/synapse/replication/slave/storage/_base.py
index 182cb2a1d8..456bc005a0 100644
--- a/synapse/replication/slave/storage/_base.py
+++ b/synapse/replication/slave/storage/_base.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import logging
+from typing import Dict
 
 import six
 
@@ -44,7 +45,14 @@ class BaseSlavedStore(SQLBaseStore):
 
         self.hs = hs
 
-    def stream_positions(self):
+    def stream_positions(self) -> Dict[str, int]:
+        """
+        Get the current positions of all the streams this store wants to subscribe to
+
+        Returns:
+            map from stream name to the most recent update we have for
+            that stream (ie, the point we want to start replicating from)
+        """
         pos = {}
         if self._cache_id_gen:
             pos["caches"] = self._cache_id_gen.get_current_token()
diff --git a/synapse/replication/slave/storage/devices.py b/synapse/replication/slave/storage/devices.py
index 61557665a7..de50748c30 100644
--- a/synapse/replication/slave/storage/devices.py
+++ b/synapse/replication/slave/storage/devices.py
@@ -15,6 +15,7 @@
 
 from synapse.replication.slave.storage._base import BaseSlavedStore
 from synapse.replication.slave.storage._slaved_id_tracker import SlavedIdTracker
+from synapse.replication.tcp.streams._base import DeviceListsStream, UserSignatureStream
 from synapse.storage.data_stores.main.devices import DeviceWorkerStore
 from synapse.storage.data_stores.main.end_to_end_keys import EndToEndKeyWorkerStore
 from synapse.util.caches.stream_change_cache import StreamChangeCache
@@ -42,14 +43,22 @@ class SlavedDeviceStore(EndToEndKeyWorkerStore, DeviceWorkerStore, BaseSlavedSto
 
     def stream_positions(self):
         result = super(SlavedDeviceStore, self).stream_positions()
-        result["device_lists"] = self._device_list_id_gen.get_current_token()
+        # The user signature stream uses the same stream ID generator as the
+        # device list stream, so set them both to the device list ID
+        # generator's current token.
+        current_token = self._device_list_id_gen.get_current_token()
+        result[DeviceListsStream.NAME] = current_token
+        result[UserSignatureStream.NAME] = current_token
         return result
 
     def process_replication_rows(self, stream_name, token, rows):
-        if stream_name == "device_lists":
+        if stream_name == DeviceListsStream.NAME:
             self._device_list_id_gen.advance(token)
             for row in rows:
                 self._invalidate_caches_for_devices(token, row.user_id, row.destination)
+        elif stream_name == UserSignatureStream.NAME:
+            for row in rows:
+                self._user_signature_stream_cache.entity_has_changed(row.user_id, token)
         return super(SlavedDeviceStore, self).process_replication_rows(
             stream_name, token, rows
         )
diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
index a44ceb00e7..fead78388c 100644
--- a/synapse/replication/tcp/client.py
+++ b/synapse/replication/tcp/client.py
@@ -16,10 +16,17 @@
 """
 
 import logging
+from typing import Dict
 
 from twisted.internet import defer
 from twisted.internet.protocol import ReconnectingClientFactory
 
+from synapse.replication.slave.storage._base import BaseSlavedStore
+from synapse.replication.tcp.protocol import (
+    AbstractReplicationClientHandler,
+    ClientReplicationStreamProtocol,
+)
+
 from .commands import (
     FederationAckCommand,
     InvalidateCacheCommand,
@@ -27,7 +34,6 @@ from .commands import (
     UserIpCommand,
     UserSyncCommand,
 )
-from .protocol import ClientReplicationStreamProtocol
 
 logger = logging.getLogger(__name__)
 
@@ -42,7 +48,7 @@ class ReplicationClientFactory(ReconnectingClientFactory):
 
     maxDelay = 30  # Try at least once every N seconds
 
-    def __init__(self, hs, client_name, handler):
+    def __init__(self, hs, client_name, handler: AbstractReplicationClientHandler):
         self.client_name = client_name
         self.handler = handler
         self.server_name = hs.config.server_name
@@ -68,13 +74,13 @@ class ReplicationClientFactory(ReconnectingClientFactory):
         ReconnectingClientFactory.clientConnectionFailed(self, connector, reason)
 
 
-class ReplicationClientHandler(object):
+class ReplicationClientHandler(AbstractReplicationClientHandler):
     """A base handler that can be passed to the ReplicationClientFactory.
 
     By default proxies incoming replication data to the SlaveStore.
     """
 
-    def __init__(self, store):
+    def __init__(self, store: BaseSlavedStore):
         self.store = store
 
         # The current connection. None if we are currently (re)connecting
@@ -138,11 +144,13 @@ class ReplicationClientHandler(object):
         if d:
             d.callback(data)
 
-    def get_streams_to_replicate(self):
+    def get_streams_to_replicate(self) -> Dict[str, int]:
         """Called when a new connection has been established and we need to
         subscribe to streams.
 
-        Returns a dictionary of stream name to token.
+        Returns:
+            map from stream name to the most recent update we have for
+            that stream (ie, the point we want to start replicating from)
         """
         args = self.store.stream_positions()
         user_account_data = args.pop("user_account_data", None)
@@ -168,7 +176,7 @@ class ReplicationClientHandler(object):
         if self.connection:
             self.connection.send_command(cmd)
         else:
-            logger.warn("Queuing command as not connected: %r", cmd.NAME)
+            logger.warning("Queuing command as not connected: %r", cmd.NAME)
             self.pending_commands.append(cmd)
 
     def send_federation_ack(self, token):
diff --git a/synapse/replication/tcp/protocol.py b/synapse/replication/tcp/protocol.py
index 5ffdf2675d..afaf002fe6 100644
--- a/synapse/replication/tcp/protocol.py
+++ b/synapse/replication/tcp/protocol.py
@@ -48,7 +48,7 @@ indicate which side is sending, these are *not* included on the wire::
     > ERROR server stopping
     * connection closed by server *
 """
-
+import abc
 import fcntl
 import logging
 import struct
@@ -65,6 +65,7 @@ from twisted.python.failure import Failure
 from synapse.logging.context import make_deferred_yieldable, run_in_background
 from synapse.metrics import LaterGauge
 from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.util import Clock
 from synapse.util.stringutils import random_string
 
 from .commands import (
@@ -249,7 +250,7 @@ class BaseReplicationStreamProtocol(LineOnlyReceiver):
         return handler(cmd)
 
     def close(self):
-        logger.warn("[%s] Closing connection", self.id())
+        logger.warning("[%s] Closing connection", self.id())
         self.time_we_closed = self.clock.time_msec()
         self.transport.loseConnection()
         self.on_connection_closed()
@@ -558,11 +559,80 @@ class ServerReplicationStreamProtocol(BaseReplicationStreamProtocol):
         self.streamer.lost_connection(self)
 
 
+class AbstractReplicationClientHandler(metaclass=abc.ABCMeta):
+    """
+    The interface for the handler that should be passed to
+    ClientReplicationStreamProtocol
+    """
+
+    @abc.abstractmethod
+    def on_rdata(self, stream_name, token, rows):
+        """Called to handle a batch of replication data with a given stream token.
+
+        Args:
+            stream_name (str): name of the replication stream for this batch of rows
+            token (int): stream token for this batch of rows
+            rows (list): a list of Stream.ROW_TYPE objects as returned by
+                Stream.parse_row.
+
+        Returns:
+            Deferred|None
+        """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def on_position(self, stream_name, token):
+        """Called when we get new position data."""
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def on_sync(self, data):
+        """Called when get a new SYNC command."""
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def get_streams_to_replicate(self):
+        """Called when a new connection has been established and we need to
+        subscribe to streams.
+
+        Returns:
+            map from stream name to the most recent update we have for
+            that stream (ie, the point we want to start replicating from)
+        """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def get_currently_syncing_users(self):
+        """Get the list of currently syncing users (if any). This is called
+        when a connection has been established and we need to send the
+        currently syncing users."""
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def update_connection(self, connection):
+        """Called when a connection has been established (or lost with None).
+        """
+        raise NotImplementedError()
+
+    @abc.abstractmethod
+    def finished_connecting(self):
+        """Called when we have successfully subscribed and caught up to all
+        streams we're interested in.
+        """
+        raise NotImplementedError()
+
+
 class ClientReplicationStreamProtocol(BaseReplicationStreamProtocol):
     VALID_INBOUND_COMMANDS = VALID_SERVER_COMMANDS
     VALID_OUTBOUND_COMMANDS = VALID_CLIENT_COMMANDS
 
-    def __init__(self, client_name, server_name, clock, handler):
+    def __init__(
+        self,
+        client_name: str,
+        server_name: str,
+        clock: Clock,
+        handler: AbstractReplicationClientHandler,
+    ):
         BaseReplicationStreamProtocol.__init__(self, clock)
 
         self.client_name = client_name
diff --git a/synapse/replication/tcp/streams/__init__.py b/synapse/replication/tcp/streams/__init__.py
index 634f636dc9..5f52264e84 100644
--- a/synapse/replication/tcp/streams/__init__.py
+++ b/synapse/replication/tcp/streams/__init__.py
@@ -45,5 +45,6 @@ STREAMS_MAP = {
         _base.TagAccountDataStream,
         _base.AccountDataStream,
         _base.GroupServerStream,
+        _base.UserSignatureStream,
     )
 }
diff --git a/synapse/replication/tcp/streams/_base.py b/synapse/replication/tcp/streams/_base.py
index f03111c259..9e45429d49 100644
--- a/synapse/replication/tcp/streams/_base.py
+++ b/synapse/replication/tcp/streams/_base.py
@@ -95,6 +95,7 @@ GroupsStreamRow = namedtuple(
     "GroupsStreamRow",
     ("group_id", "user_id", "type", "content"),  # str  # str  # str  # dict
 )
+UserSignatureStreamRow = namedtuple("UserSignatureStreamRow", ("user_id"))  # str
 
 
 class Stream(object):
@@ -438,3 +439,20 @@ class GroupServerStream(Stream):
         self.update_function = store.get_all_groups_changes
 
         super(GroupServerStream, self).__init__(hs)
+
+
+class UserSignatureStream(Stream):
+    """A user has signed their own device with their user-signing key
+    """
+
+    NAME = "user_signature"
+    _LIMITED = False
+    ROW_TYPE = UserSignatureStreamRow
+
+    def __init__(self, hs):
+        store = hs.get_datastore()
+
+        self.current_token = store.get_device_stream_token
+        self.update_function = store.get_all_user_signature_changes_for_remotes
+
+        super(UserSignatureStream, self).__init__(hs)
diff --git a/synapse/rest/admin/__init__.py b/synapse/rest/admin/__init__.py
index 939418ee2b..5c2a2eb593 100644
--- a/synapse/rest/admin/__init__.py
+++ b/synapse/rest/admin/__init__.py
@@ -286,7 +286,7 @@ class PurgeHistoryRestServlet(RestServlet):
                 room_id, stream_ordering
             )
             if not r:
-                logger.warn(
+                logger.warning(
                     "[purge] purging events not possible: No event found "
                     "(received_ts %i => stream_ordering %i)",
                     ts,
diff --git a/synapse/rest/client/v1/login.py b/synapse/rest/client/v1/login.py
index 8414af08cb..24a0ce74f2 100644
--- a/synapse/rest/client/v1/login.py
+++ b/synapse/rest/client/v1/login.py
@@ -203,10 +203,11 @@ class LoginRestServlet(RestServlet):
                 address = address.lower()
 
             # Check for login providers that support 3pid login types
-            canonical_user_id, callback_3pid = (
-                yield self.auth_handler.check_password_provider_3pid(
-                    medium, address, login_submission["password"]
-                )
+            (
+                canonical_user_id,
+                callback_3pid,
+            ) = yield self.auth_handler.check_password_provider_3pid(
+                medium, address, login_submission["password"]
             )
             if canonical_user_id:
                 # Authentication through password provider and 3pid succeeded
@@ -221,7 +222,7 @@ class LoginRestServlet(RestServlet):
                 medium, address
             )
             if not user_id:
-                logger.warn(
+                logger.warning(
                     "unknown 3pid identifier medium %s, address %r", medium, address
                 )
                 raise LoginError(403, "", errcode=Codes.FORBIDDEN)
@@ -280,8 +281,8 @@ class LoginRestServlet(RestServlet):
     def do_token_login(self, login_submission):
         token = login_submission["token"]
         auth_handler = self.auth_handler
-        user_id = (
-            yield auth_handler.validate_short_term_login_token_and_get_user_id(token)
+        user_id = yield auth_handler.validate_short_term_login_token_and_get_user_id(
+            token
         )
 
         result = yield self._register_device_with_callback(user_id, login_submission)
@@ -380,7 +381,7 @@ class CasTicketServlet(RestServlet):
         self.cas_displayname_attribute = hs.config.cas_displayname_attribute
         self.cas_required_attributes = hs.config.cas_required_attributes
         self._sso_auth_handler = SSOAuthHandler(hs)
-        self._http_client = hs.get_simple_http_client()
+        self._http_client = hs.get_proxied_http_client()
 
     @defer.inlineCallbacks
     def on_GET(self, request):
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 9c1d41421c..86bbcc0eea 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -21,8 +21,6 @@ from six.moves.urllib import parse as urlparse
 
 from canonicaljson import json
 
-from twisted.internet import defer
-
 from synapse.api.constants import EventTypes, Membership
 from synapse.api.errors import (
     AuthError,
@@ -85,11 +83,10 @@ class RoomCreateRestServlet(TransactionRestServlet):
         set_tag("txn_id", txn_id)
         return self.txns.fetch_or_execute_request(request, self.on_POST, request)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
 
-        info = yield self._room_creation_handler.create_room(
+        info = await self._room_creation_handler.create_room(
             requester, self.get_room_config(request)
         )
 
@@ -154,15 +151,14 @@ class RoomStateEventRestServlet(TransactionRestServlet):
     def on_PUT_no_state_key(self, request, room_id, event_type):
         return self.on_PUT(request, room_id, event_type, "")
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, event_type, state_key):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id, event_type, state_key):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         format = parse_string(
             request, "format", default="content", allowed_values=["content", "event"]
         )
 
         msg_handler = self.message_handler
-        data = yield msg_handler.get_room_data(
+        data = await msg_handler.get_room_data(
             user_id=requester.user.to_string(),
             room_id=room_id,
             event_type=event_type,
@@ -179,9 +175,8 @@ class RoomStateEventRestServlet(TransactionRestServlet):
         elif format == "content":
             return 200, data.get_dict()["content"]
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, room_id, event_type, state_key, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, room_id, event_type, state_key, txn_id=None):
+        requester = await self.auth.get_user_by_req(request)
 
         if txn_id:
             set_tag("txn_id", txn_id)
@@ -200,7 +195,7 @@ class RoomStateEventRestServlet(TransactionRestServlet):
 
         if event_type == EventTypes.Member:
             membership = content.get("membership", None)
-            event = yield self.room_member_handler.update_membership(
+            event = await self.room_member_handler.update_membership(
                 requester,
                 target=UserID.from_string(state_key),
                 room_id=room_id,
@@ -208,7 +203,7 @@ class RoomStateEventRestServlet(TransactionRestServlet):
                 content=content,
             )
         else:
-            event = yield self.event_creation_handler.create_and_send_nonmember_event(
+            event = await self.event_creation_handler.create_and_send_nonmember_event(
                 requester, event_dict, txn_id=txn_id
             )
 
@@ -231,9 +226,8 @@ class RoomSendEventRestServlet(TransactionRestServlet):
         PATTERNS = "/rooms/(?P<room_id>[^/]*)/send/(?P<event_type>[^/]*)"
         register_txn_path(self, PATTERNS, http_server, with_get=True)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, event_type, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request, room_id, event_type, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         content = parse_json_object_from_request(request)
 
         event_dict = {
@@ -246,7 +240,7 @@ class RoomSendEventRestServlet(TransactionRestServlet):
         if b"ts" in request.args and requester.app_service:
             event_dict["origin_server_ts"] = parse_integer(request, "ts", 0)
 
-        event = yield self.event_creation_handler.create_and_send_nonmember_event(
+        event = await self.event_creation_handler.create_and_send_nonmember_event(
             requester, event_dict, txn_id=txn_id
         )
 
@@ -276,9 +270,8 @@ class JoinRoomAliasServlet(TransactionRestServlet):
         PATTERNS = "/join/(?P<room_identifier>[^/]*)"
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_identifier, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request, room_identifier, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         try:
             content = parse_json_object_from_request(request)
@@ -298,14 +291,14 @@ class JoinRoomAliasServlet(TransactionRestServlet):
         elif RoomAlias.is_valid(room_identifier):
             handler = self.room_member_handler
             room_alias = RoomAlias.from_string(room_identifier)
-            room_id, remote_room_hosts = yield handler.lookup_room_alias(room_alias)
+            room_id, remote_room_hosts = await handler.lookup_room_alias(room_alias)
             room_id = room_id.to_string()
         else:
             raise SynapseError(
                 400, "%s was not legal room ID or room alias" % (room_identifier,)
             )
 
-        yield self.room_member_handler.update_membership(
+        await self.room_member_handler.update_membership(
             requester=requester,
             target=requester.user,
             room_id=room_id,
@@ -335,12 +328,11 @@ class PublicRoomListRestServlet(TransactionRestServlet):
         self.hs = hs
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
+    async def on_GET(self, request):
         server = parse_string(request, "server", default=None)
 
         try:
-            yield self.auth.get_user_by_req(request, allow_guest=True)
+            await self.auth.get_user_by_req(request, allow_guest=True)
         except InvalidClientCredentialsError as e:
             # Option to allow servers to require auth when accessing
             # /publicRooms via CS API. This is especially helpful in private
@@ -367,19 +359,18 @@ class PublicRoomListRestServlet(TransactionRestServlet):
 
         handler = self.hs.get_room_list_handler()
         if server:
-            data = yield handler.get_remote_public_room_list(
+            data = await handler.get_remote_public_room_list(
                 server, limit=limit, since_token=since_token
             )
         else:
-            data = yield handler.get_local_public_room_list(
+            data = await handler.get_local_public_room_list(
                 limit=limit, since_token=since_token
             )
 
         return 200, data
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request):
+        await self.auth.get_user_by_req(request, allow_guest=True)
 
         server = parse_string(request, "server", default=None)
         content = parse_json_object_from_request(request)
@@ -408,7 +399,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
 
         handler = self.hs.get_room_list_handler()
         if server:
-            data = yield handler.get_remote_public_room_list(
+            data = await handler.get_remote_public_room_list(
                 server,
                 limit=limit,
                 since_token=since_token,
@@ -417,7 +408,7 @@ class PublicRoomListRestServlet(TransactionRestServlet):
                 third_party_instance_id=third_party_instance_id,
             )
         else:
-            data = yield handler.get_local_public_room_list(
+            data = await handler.get_local_public_room_list(
                 limit=limit,
                 since_token=since_token,
                 search_filter=search_filter,
@@ -436,10 +427,9 @@ class RoomMemberListRestServlet(RestServlet):
         self.message_handler = hs.get_message_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
+    async def on_GET(self, request, room_id):
         # TODO support Pagination stream API (limit/tokens)
-        requester = yield self.auth.get_user_by_req(request)
+        requester = await self.auth.get_user_by_req(request)
         handler = self.message_handler
 
         # request the state as of a given event, as identified by a stream token,
@@ -459,7 +449,7 @@ class RoomMemberListRestServlet(RestServlet):
         membership = parse_string(request, "membership")
         not_membership = parse_string(request, "not_membership")
 
-        events = yield handler.get_state_events(
+        events = await handler.get_state_events(
             room_id=room_id,
             user_id=requester.user.to_string(),
             at_token=at_token,
@@ -488,11 +478,10 @@ class JoinedRoomMemberListRestServlet(RestServlet):
         self.message_handler = hs.get_message_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
 
-        users_with_profile = yield self.message_handler.get_joined_members(
+        users_with_profile = await self.message_handler.get_joined_members(
             requester, room_id
         )
 
@@ -508,9 +497,8 @@ class RoomMessageListRestServlet(RestServlet):
         self.pagination_handler = hs.get_pagination_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         pagination_config = PaginationConfig.from_request(request, default_limit=10)
         as_client_event = b"raw" not in request.args
         filter_bytes = parse_string(request, b"filter", encoding=None)
@@ -521,7 +509,7 @@ class RoomMessageListRestServlet(RestServlet):
                 as_client_event = False
         else:
             event_filter = None
-        msgs = yield self.pagination_handler.get_messages(
+        msgs = await self.pagination_handler.get_messages(
             room_id=room_id,
             requester=requester,
             pagin_config=pagination_config,
@@ -541,11 +529,10 @@ class RoomStateRestServlet(RestServlet):
         self.message_handler = hs.get_message_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         # Get all the current state for this room
-        events = yield self.message_handler.get_state_events(
+        events = await self.message_handler.get_state_events(
             room_id=room_id,
             user_id=requester.user.to_string(),
             is_guest=requester.is_guest,
@@ -562,11 +549,10 @@ class RoomInitialSyncRestServlet(RestServlet):
         self.initial_sync_handler = hs.get_initial_sync_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         pagination_config = PaginationConfig.from_request(request)
-        content = yield self.initial_sync_handler.room_initial_sync(
+        content = await self.initial_sync_handler.room_initial_sync(
             room_id=room_id, requester=requester, pagin_config=pagination_config
         )
         return 200, content
@@ -584,11 +570,10 @@ class RoomEventServlet(RestServlet):
         self._event_serializer = hs.get_event_client_serializer()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, event_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id, event_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
         try:
-            event = yield self.event_handler.get_event(
+            event = await self.event_handler.get_event(
                 requester.user, room_id, event_id
             )
         except AuthError:
@@ -599,7 +584,7 @@ class RoomEventServlet(RestServlet):
 
         time_now = self.clock.time_msec()
         if event:
-            event = yield self._event_serializer.serialize_event(event, time_now)
+            event = await self._event_serializer.serialize_event(event, time_now)
             return 200, event
 
         return SynapseError(404, "Event not found.", errcode=Codes.NOT_FOUND)
@@ -617,9 +602,8 @@ class RoomEventContextServlet(RestServlet):
         self._event_serializer = hs.get_event_client_serializer()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request, room_id, event_id):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request, room_id, event_id):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         limit = parse_integer(request, "limit", default=10)
 
@@ -631,7 +615,7 @@ class RoomEventContextServlet(RestServlet):
         else:
             event_filter = None
 
-        results = yield self.room_context_handler.get_event_context(
+        results = await self.room_context_handler.get_event_context(
             requester.user, room_id, event_id, limit, event_filter
         )
 
@@ -639,16 +623,16 @@ class RoomEventContextServlet(RestServlet):
             raise SynapseError(404, "Event not found.", errcode=Codes.NOT_FOUND)
 
         time_now = self.clock.time_msec()
-        results["events_before"] = yield self._event_serializer.serialize_events(
+        results["events_before"] = await self._event_serializer.serialize_events(
             results["events_before"], time_now
         )
-        results["event"] = yield self._event_serializer.serialize_event(
+        results["event"] = await self._event_serializer.serialize_event(
             results["event"], time_now
         )
-        results["events_after"] = yield self._event_serializer.serialize_events(
+        results["events_after"] = await self._event_serializer.serialize_events(
             results["events_after"], time_now
         )
-        results["state"] = yield self._event_serializer.serialize_events(
+        results["state"] = await self._event_serializer.serialize_events(
             results["state"], time_now
         )
 
@@ -665,11 +649,10 @@ class RoomForgetRestServlet(TransactionRestServlet):
         PATTERNS = "/rooms/(?P<room_id>[^/]*)/forget"
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=False)
+    async def on_POST(self, request, room_id, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=False)
 
-        yield self.room_member_handler.forget(user=requester.user, room_id=room_id)
+        await self.room_member_handler.forget(user=requester.user, room_id=room_id)
 
         return 200, {}
 
@@ -696,9 +679,8 @@ class RoomMembershipRestServlet(TransactionRestServlet):
         )
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, membership_action, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_POST(self, request, room_id, membership_action, txn_id=None):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
         if requester.is_guest and membership_action not in {
             Membership.JOIN,
@@ -714,7 +696,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
             content = {}
 
         if membership_action == "invite" and self._has_3pid_invite_keys(content):
-            yield self.room_member_handler.do_3pid_invite(
+            await self.room_member_handler.do_3pid_invite(
                 room_id,
                 requester.user,
                 content["medium"],
@@ -735,7 +717,7 @@ class RoomMembershipRestServlet(TransactionRestServlet):
         if "reason" in content and membership_action in ["kick", "ban"]:
             event_content = {"reason": content["reason"]}
 
-        yield self.room_member_handler.update_membership(
+        await self.room_member_handler.update_membership(
             requester=requester,
             target=target,
             room_id=room_id,
@@ -777,12 +759,11 @@ class RoomRedactEventRestServlet(TransactionRestServlet):
         PATTERNS = "/rooms/(?P<room_id>[^/]*)/redact/(?P<event_id>[^/]*)"
         register_txn_path(self, PATTERNS, http_server)
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, event_id, txn_id=None):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id, event_id, txn_id=None):
+        requester = await self.auth.get_user_by_req(request)
         content = parse_json_object_from_request(request)
 
-        event = yield self.event_creation_handler.create_and_send_nonmember_event(
+        event = await self.event_creation_handler.create_and_send_nonmember_event(
             requester,
             {
                 "type": EventTypes.Redaction,
@@ -816,29 +797,28 @@ class RoomTypingRestServlet(RestServlet):
         self.typing_handler = hs.get_typing_handler()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_PUT(self, request, room_id, user_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_PUT(self, request, room_id, user_id):
+        requester = await self.auth.get_user_by_req(request)
 
         room_id = urlparse.unquote(room_id)
         target_user = UserID.from_string(urlparse.unquote(user_id))
 
         content = parse_json_object_from_request(request)
 
-        yield self.presence_handler.bump_presence_active_time(requester.user)
+        await self.presence_handler.bump_presence_active_time(requester.user)
 
         # Limit timeout to stop people from setting silly typing timeouts.
         timeout = min(content.get("timeout", 30000), 120000)
 
         if content["typing"]:
-            yield self.typing_handler.started_typing(
+            await self.typing_handler.started_typing(
                 target_user=target_user,
                 auth_user=requester.user,
                 room_id=room_id,
                 timeout=timeout,
             )
         else:
-            yield self.typing_handler.stopped_typing(
+            await self.typing_handler.stopped_typing(
                 target_user=target_user, auth_user=requester.user, room_id=room_id
             )
 
@@ -853,14 +833,13 @@ class SearchRestServlet(RestServlet):
         self.handlers = hs.get_handlers()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request):
+        requester = await self.auth.get_user_by_req(request)
 
         content = parse_json_object_from_request(request)
 
         batch = parse_string(request, "next_batch")
-        results = yield self.handlers.search_handler.search(
+        results = await self.handlers.search_handler.search(
             requester.user, content, batch
         )
 
@@ -875,11 +854,10 @@ class JoinedRoomsRestServlet(RestServlet):
         self.store = hs.get_datastore()
         self.auth = hs.get_auth()
 
-    @defer.inlineCallbacks
-    def on_GET(self, request):
-        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
+    async def on_GET(self, request):
+        requester = await self.auth.get_user_by_req(request, allow_guest=True)
 
-        room_ids = yield self.store.get_rooms_for_user(requester.user.to_string())
+        room_ids = await self.store.get_rooms_for_user(requester.user.to_string())
         return 200, {"joined_rooms": list(room_ids)}
 
 
diff --git a/synapse/rest/client/v2_alpha/account.py b/synapse/rest/client/v2_alpha/account.py
index 80cf7126a0..f26eae794c 100644
--- a/synapse/rest/client/v2_alpha/account.py
+++ b/synapse/rest/client/v2_alpha/account.py
@@ -71,7 +71,7 @@ class EmailPasswordRequestTokenRestServlet(RestServlet):
     def on_POST(self, request):
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "User password resets have been disabled due to lack of email config"
                 )
             raise SynapseError(
@@ -148,7 +148,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
         if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
-            self.failure_email_template, = load_jinja2_templates(
+            (self.failure_email_template,) = load_jinja2_templates(
                 self.config.email_template_dir,
                 [self.config.email_password_reset_template_failure_html],
             )
@@ -162,7 +162,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
             )
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "Password reset emails have been disabled due to lack of an email config"
                 )
             raise SynapseError(
@@ -183,7 +183,7 @@ class PasswordResetSubmitTokenServlet(RestServlet):
             # Perform a 302 redirect if next_link is set
             if next_link:
                 if next_link.startswith("file:///"):
-                    logger.warn(
+                    logger.warning(
                         "Not redirecting to next_link as it is a local file: address"
                     )
                 else:
@@ -350,7 +350,7 @@ class EmailThreepidRequestTokenRestServlet(RestServlet):
     def on_POST(self, request):
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "Adding emails have been disabled due to lack of an email config"
                 )
             raise SynapseError(
@@ -441,7 +441,7 @@ class MsisdnThreepidRequestTokenRestServlet(RestServlet):
             raise SynapseError(400, "MSISDN is already in use", Codes.THREEPID_IN_USE)
 
         if not self.hs.config.account_threepid_delegate_msisdn:
-            logger.warn(
+            logger.warning(
                 "No upstream msisdn account_threepid_delegate configured on the server to "
                 "handle this request"
             )
@@ -479,7 +479,7 @@ class AddThreepidEmailSubmitTokenServlet(RestServlet):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
         if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
-            self.failure_email_template, = load_jinja2_templates(
+            (self.failure_email_template,) = load_jinja2_templates(
                 self.config.email_template_dir,
                 [self.config.email_add_threepid_template_failure_html],
             )
@@ -488,7 +488,7 @@ class AddThreepidEmailSubmitTokenServlet(RestServlet):
     def on_GET(self, request):
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "Adding emails have been disabled due to lack of an email config"
                 )
             raise SynapseError(
@@ -515,7 +515,7 @@ class AddThreepidEmailSubmitTokenServlet(RestServlet):
             # Perform a 302 redirect if next_link is set
             if next_link:
                 if next_link.startswith("file:///"):
-                    logger.warn(
+                    logger.warning(
                         "Not redirecting to next_link as it is a local file: address"
                     )
                 else:
diff --git a/synapse/rest/client/v2_alpha/read_marker.py b/synapse/rest/client/v2_alpha/read_marker.py
index b3bf8567e1..67cbc37312 100644
--- a/synapse/rest/client/v2_alpha/read_marker.py
+++ b/synapse/rest/client/v2_alpha/read_marker.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.http.servlet import RestServlet, parse_json_object_from_request
 
 from ._base import client_patterns
@@ -34,17 +32,16 @@ class ReadMarkerRestServlet(RestServlet):
         self.read_marker_handler = hs.get_read_marker_handler()
         self.presence_handler = hs.get_presence_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id):
+        requester = await self.auth.get_user_by_req(request)
 
-        yield self.presence_handler.bump_presence_active_time(requester.user)
+        await self.presence_handler.bump_presence_active_time(requester.user)
 
         body = parse_json_object_from_request(request)
 
         read_event_id = body.get("m.read", None)
         if read_event_id:
-            yield self.receipts_handler.received_client_receipt(
+            await self.receipts_handler.received_client_receipt(
                 room_id,
                 "m.read",
                 user_id=requester.user.to_string(),
@@ -53,7 +50,7 @@ class ReadMarkerRestServlet(RestServlet):
 
         read_marker_event_id = body.get("m.fully_read", None)
         if read_marker_event_id:
-            yield self.read_marker_handler.received_client_read_marker(
+            await self.read_marker_handler.received_client_read_marker(
                 room_id,
                 user_id=requester.user.to_string(),
                 event_id=read_marker_event_id,
diff --git a/synapse/rest/client/v2_alpha/receipts.py b/synapse/rest/client/v2_alpha/receipts.py
index 0dab03d227..92555bd4a9 100644
--- a/synapse/rest/client/v2_alpha/receipts.py
+++ b/synapse/rest/client/v2_alpha/receipts.py
@@ -15,8 +15,6 @@
 
 import logging
 
-from twisted.internet import defer
-
 from synapse.api.errors import SynapseError
 from synapse.http.servlet import RestServlet
 
@@ -39,16 +37,15 @@ class ReceiptRestServlet(RestServlet):
         self.receipts_handler = hs.get_receipts_handler()
         self.presence_handler = hs.get_presence_handler()
 
-    @defer.inlineCallbacks
-    def on_POST(self, request, room_id, receipt_type, event_id):
-        requester = yield self.auth.get_user_by_req(request)
+    async def on_POST(self, request, room_id, receipt_type, event_id):
+        requester = await self.auth.get_user_by_req(request)
 
         if receipt_type != "m.read":
             raise SynapseError(400, "Receipt type must be 'm.read'")
 
-        yield self.presence_handler.bump_presence_active_time(requester.user)
+        await self.presence_handler.bump_presence_active_time(requester.user)
 
-        yield self.receipts_handler.received_client_receipt(
+        await self.receipts_handler.received_client_receipt(
             room_id, receipt_type, user_id=requester.user.to_string(), event_id=event_id
         )
 
diff --git a/synapse/rest/client/v2_alpha/register.py b/synapse/rest/client/v2_alpha/register.py
index 4f24a124a6..91db923814 100644
--- a/synapse/rest/client/v2_alpha/register.py
+++ b/synapse/rest/client/v2_alpha/register.py
@@ -106,7 +106,7 @@ class EmailRegisterRequestTokenRestServlet(RestServlet):
     def on_POST(self, request):
         if self.hs.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.hs.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "Email registration has been disabled due to lack of email config"
                 )
             raise SynapseError(
@@ -207,7 +207,7 @@ class MsisdnRegisterRequestTokenRestServlet(RestServlet):
             )
 
         if not self.hs.config.account_threepid_delegate_msisdn:
-            logger.warn(
+            logger.warning(
                 "No upstream msisdn account_threepid_delegate configured on the server to "
                 "handle this request"
             )
@@ -247,13 +247,13 @@ class RegistrationSubmitTokenServlet(RestServlet):
         self.store = hs.get_datastore()
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
-            self.failure_email_template, = load_jinja2_templates(
+            (self.failure_email_template,) = load_jinja2_templates(
                 self.config.email_template_dir,
                 [self.config.email_registration_template_failure_html],
             )
 
         if self.config.threepid_behaviour_email == ThreepidBehaviour.LOCAL:
-            self.failure_email_template, = load_jinja2_templates(
+            (self.failure_email_template,) = load_jinja2_templates(
                 self.config.email_template_dir,
                 [self.config.email_registration_template_failure_html],
             )
@@ -266,7 +266,7 @@ class RegistrationSubmitTokenServlet(RestServlet):
             )
         if self.config.threepid_behaviour_email == ThreepidBehaviour.OFF:
             if self.config.local_threepid_handling_disabled_due_to_email_config:
-                logger.warn(
+                logger.warning(
                     "User registration via email has been disabled due to lack of email config"
                 )
             raise SynapseError(
@@ -287,7 +287,7 @@ class RegistrationSubmitTokenServlet(RestServlet):
             # Perform a 302 redirect if next_link is set
             if next_link:
                 if next_link.startswith("file:///"):
-                    logger.warn(
+                    logger.warning(
                         "Not redirecting to next_link as it is a local file: address"
                     )
                 else:
@@ -480,7 +480,7 @@ class RegisterRestServlet(RestServlet):
             # a password to work around a client bug where it sent
             # the 'initial_device_display_name' param alone, wiping out
             # the original registration params
-            logger.warn("Ignoring initial_device_display_name without password")
+            logger.warning("Ignoring initial_device_display_name without password")
             del body["initial_device_display_name"]
 
         session_id = self.auth_handler.get_session_id(body)
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index a883c8adda..ccd8b17b23 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -112,9 +112,14 @@ class SyncRestServlet(RestServlet):
         full_state = parse_boolean(request, "full_state", default=False)
 
         logger.debug(
-            "/sync: user=%r, timeout=%r, since=%r,"
-            " set_presence=%r, filter_id=%r, device_id=%r"
-            % (user, timeout, since, set_presence, filter_id, device_id)
+            "/sync: user=%r, timeout=%r, since=%r, "
+            "set_presence=%r, filter_id=%r, device_id=%r",
+            user,
+            timeout,
+            since,
+            set_presence,
+            filter_id,
+            device_id,
         )
 
         request_key = (user, timeout, since, filter_id, full_state, device_id)
@@ -389,7 +394,7 @@ class SyncRestServlet(RestServlet):
             # We've had bug reports that events were coming down under the
             # wrong room.
             if event.room_id != room.room_id:
-                logger.warn(
+                logger.warning(
                     "Event %r is under room %r instead of %r",
                     event.event_id,
                     room.room_id,
diff --git a/synapse/rest/client/versions.py b/synapse/rest/client/versions.py
index 1044ae7b4e..bb30ce3f34 100644
--- a/synapse/rest/client/versions.py
+++ b/synapse/rest/client/versions.py
@@ -65,6 +65,9 @@ class VersionsRestServlet(RestServlet):
                     "m.require_identity_server": False,
                     # as per MSC2290
                     "m.separate_add_and_bind": True,
+                    # Implements support for label-based filtering as described in
+                    # MSC2326.
+                    "org.matrix.label_based_filtering": True,
                 },
             },
         )
diff --git a/synapse/rest/key/v2/remote_key_resource.py b/synapse/rest/key/v2/remote_key_resource.py
index 55580bc59e..e7fc3f0431 100644
--- a/synapse/rest/key/v2/remote_key_resource.py
+++ b/synapse/rest/key/v2/remote_key_resource.py
@@ -102,7 +102,7 @@ class RemoteKey(DirectServeResource):
     @wrap_json_request_handler
     async def _async_render_GET(self, request):
         if len(request.postpath) == 1:
-            server, = request.postpath
+            (server,) = request.postpath
             query = {server.decode("ascii"): {}}
         elif len(request.postpath) == 2:
             server, key_id = request.postpath
diff --git a/synapse/rest/media/v1/media_repository.py b/synapse/rest/media/v1/media_repository.py
index b972e152a9..bd9186fe50 100644
--- a/synapse/rest/media/v1/media_repository.py
+++ b/synapse/rest/media/v1/media_repository.py
@@ -363,7 +363,7 @@ class MediaRepository(object):
                     },
                 )
             except RequestSendFailed as e:
-                logger.warn(
+                logger.warning(
                     "Request failed fetching remote media %s/%s: %r",
                     server_name,
                     media_id,
@@ -372,7 +372,7 @@ class MediaRepository(object):
                 raise SynapseError(502, "Failed to fetch remote media")
 
             except HttpResponseException as e:
-                logger.warn(
+                logger.warning(
                     "HTTP error fetching remote media %s/%s: %s",
                     server_name,
                     media_id,
@@ -383,10 +383,12 @@ class MediaRepository(object):
                 raise SynapseError(502, "Failed to fetch remote media")
 
             except SynapseError:
-                logger.warn("Failed to fetch remote media %s/%s", server_name, media_id)
+                logger.warning(
+                    "Failed to fetch remote media %s/%s", server_name, media_id
+                )
                 raise
             except NotRetryingDestination:
-                logger.warn("Not retrying destination %r", server_name)
+                logger.warning("Not retrying destination %r", server_name)
                 raise SynapseError(502, "Failed to fetch remote media")
             except Exception:
                 logger.exception(
@@ -691,7 +693,7 @@ class MediaRepository(object):
                 try:
                     os.remove(full_path)
                 except OSError as e:
-                    logger.warn("Failed to remove file: %r", full_path)
+                    logger.warning("Failed to remove file: %r", full_path)
                     if e.errno == errno.ENOENT:
                         pass
                     else:
diff --git a/synapse/rest/media/v1/preview_url_resource.py b/synapse/rest/media/v1/preview_url_resource.py
index 4d4b3c1462..69544b3711 100644
--- a/synapse/rest/media/v1/preview_url_resource.py
+++ b/synapse/rest/media/v1/preview_url_resource.py
@@ -77,6 +77,8 @@ class PreviewUrlResource(DirectServeResource):
             treq_args={"browser_like_redirects": True},
             ip_whitelist=hs.config.url_preview_ip_range_whitelist,
             ip_blacklist=hs.config.url_preview_ip_range_blacklist,
+            http_proxy=os.getenv("http_proxy"),
+            https_proxy=os.getenv("HTTPS_PROXY"),
         )
         self.media_repo = media_repo
         self.primary_base_path = media_repo.primary_base_path
@@ -120,8 +122,10 @@ class PreviewUrlResource(DirectServeResource):
                 pattern = entry[attrib]
                 value = getattr(url_tuple, attrib)
                 logger.debug(
-                    ("Matching attrib '%s' with value '%s' against" " pattern '%s'")
-                    % (attrib, value, pattern)
+                    "Matching attrib '%s' with value '%s' against" " pattern '%s'",
+                    attrib,
+                    value,
+                    pattern,
                 )
 
                 if value is None:
@@ -137,7 +141,7 @@ class PreviewUrlResource(DirectServeResource):
                         match = False
                         continue
             if match:
-                logger.warn("URL %s blocked by url_blacklist entry %s", url, entry)
+                logger.warning("URL %s blocked by url_blacklist entry %s", url, entry)
                 raise SynapseError(
                     403, "URL blocked by url pattern blacklist entry", Codes.UNKNOWN
                 )
@@ -189,7 +193,7 @@ class PreviewUrlResource(DirectServeResource):
 
         media_info = yield self._download_url(url, user)
 
-        logger.debug("got media_info of '%s'" % media_info)
+        logger.debug("got media_info of '%s'", media_info)
 
         if _is_media(media_info["media_type"]):
             file_id = media_info["filesystem_id"]
@@ -209,7 +213,7 @@ class PreviewUrlResource(DirectServeResource):
                 og["og:image:width"] = dims["width"]
                 og["og:image:height"] = dims["height"]
             else:
-                logger.warn("Couldn't get dims for %s" % url)
+                logger.warning("Couldn't get dims for %s" % url)
 
             # define our OG response for this media
         elif _is_html(media_info["media_type"]):
@@ -257,7 +261,7 @@ class PreviewUrlResource(DirectServeResource):
                         og["og:image:width"] = dims["width"]
                         og["og:image:height"] = dims["height"]
                     else:
-                        logger.warn("Couldn't get dims for %s" % og["og:image"])
+                        logger.warning("Couldn't get dims for %s", og["og:image"])
 
                     og["og:image"] = "mxc://%s/%s" % (
                         self.server_name,
@@ -268,7 +272,7 @@ class PreviewUrlResource(DirectServeResource):
                 else:
                     del og["og:image"]
         else:
-            logger.warn("Failed to find any OG data in %s", url)
+            logger.warning("Failed to find any OG data in %s", url)
             og = {}
 
         # filter out any stupidly long values
@@ -282,7 +286,7 @@ class PreviewUrlResource(DirectServeResource):
         for k in keys_to_remove:
             del og[k]
 
-        logger.debug("Calculated OG for %s as %s" % (url, og))
+        logger.debug("Calculated OG for %s as %s", url, og)
 
         jsonog = json.dumps(og)
 
@@ -311,7 +315,7 @@ class PreviewUrlResource(DirectServeResource):
 
         with self.media_storage.store_into_file(file_info) as (f, fname, finish):
             try:
-                logger.debug("Trying to get url '%s'" % url)
+                logger.debug("Trying to get url '%s'", url)
                 length, headers, uri, code = yield self.client.get_file(
                     url, output_stream=f, max_size=self.max_spider_size
                 )
@@ -331,7 +335,7 @@ class PreviewUrlResource(DirectServeResource):
                 )
             except Exception as e:
                 # FIXME: pass through 404s and other error messages nicely
-                logger.warn("Error downloading %s: %r", url, e)
+                logger.warning("Error downloading %s: %r", url, e)
 
                 raise SynapseError(
                     500,
@@ -412,7 +416,7 @@ class PreviewUrlResource(DirectServeResource):
             except OSError as e:
                 # If the path doesn't exist, meh
                 if e.errno != errno.ENOENT:
-                    logger.warn("Failed to remove media: %r: %s", media_id, e)
+                    logger.warning("Failed to remove media: %r: %s", media_id, e)
                     continue
 
             removed_media.append(media_id)
@@ -444,7 +448,7 @@ class PreviewUrlResource(DirectServeResource):
             except OSError as e:
                 # If the path doesn't exist, meh
                 if e.errno != errno.ENOENT:
-                    logger.warn("Failed to remove media: %r: %s", media_id, e)
+                    logger.warning("Failed to remove media: %r: %s", media_id, e)
                     continue
 
             try:
@@ -460,7 +464,7 @@ class PreviewUrlResource(DirectServeResource):
             except OSError as e:
                 # If the path doesn't exist, meh
                 if e.errno != errno.ENOENT:
-                    logger.warn("Failed to remove media: %r: %s", media_id, e)
+                    logger.warning("Failed to remove media: %r: %s", media_id, e)
                     continue
 
             removed_media.append(media_id)
diff --git a/synapse/rest/media/v1/thumbnail_resource.py b/synapse/rest/media/v1/thumbnail_resource.py
index 08329884ac..931ce79be8 100644
--- a/synapse/rest/media/v1/thumbnail_resource.py
+++ b/synapse/rest/media/v1/thumbnail_resource.py
@@ -182,7 +182,7 @@ class ThumbnailResource(DirectServeResource):
         if file_path:
             yield respond_with_file(request, desired_type, file_path)
         else:
-            logger.warn("Failed to generate thumbnail")
+            logger.warning("Failed to generate thumbnail")
             respond_404(request)
 
     @defer.inlineCallbacks
@@ -245,7 +245,7 @@ class ThumbnailResource(DirectServeResource):
         if file_path:
             yield respond_with_file(request, desired_type, file_path)
         else:
-            logger.warn("Failed to generate thumbnail")
+            logger.warning("Failed to generate thumbnail")
             respond_404(request)
 
     @defer.inlineCallbacks
diff --git a/synapse/server.py b/synapse/server.py
index 1fcc7375d3..90c3b072e8 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -23,6 +23,7 @@
 # Imports required for the default HomeServer() implementation
 import abc
 import logging
+import os
 
 from twisted.enterprise import adbapi
 from twisted.mail.smtp import sendmail
@@ -95,6 +96,7 @@ from synapse.server_notices.worker_server_notices_sender import (
     WorkerServerNoticesSender,
 )
 from synapse.state import StateHandler, StateResolutionHandler
+from synapse.storage import DataStores, Storage
 from synapse.streams.events import EventSources
 from synapse.util import Clock
 from synapse.util.distributor import Distributor
@@ -167,6 +169,7 @@ class HomeServer(object):
         "filtering",
         "http_client_context_factory",
         "simple_http_client",
+        "proxied_http_client",
         "media_repository",
         "media_repository_resource",
         "federation_transport_client",
@@ -196,6 +199,7 @@ class HomeServer(object):
         "account_validity_handler",
         "saml_handler",
         "event_client_serializer",
+        "storage",
     ]
 
     REQUIRED_ON_MASTER_STARTUP = ["user_directory_handler", "stats_handler"]
@@ -217,6 +221,7 @@ class HomeServer(object):
         self.hostname = hostname
         self._building = {}
         self._listening_services = []
+        self.start_time = None
 
         self.clock = Clock(reactor)
         self.distributor = Distributor()
@@ -224,7 +229,7 @@ class HomeServer(object):
         self.admin_redaction_ratelimiter = Ratelimiter()
         self.registration_ratelimiter = Ratelimiter()
 
-        self.datastore = None
+        self.datastores = None
 
         # Other kwargs are explicit dependencies
         for depname in kwargs:
@@ -233,8 +238,10 @@ class HomeServer(object):
     def setup(self):
         logger.info("Setting up.")
         with self.get_db_conn() as conn:
-            self.datastore = self.DATASTORE_CLASS(conn, self)
+            datastore = self.DATASTORE_CLASS(conn, self)
+            self.datastores = DataStores(datastore, conn, self)
             conn.commit()
+        self.start_time = int(self.get_clock().time())
         logger.info("Finished setting up.")
 
     def setup_master(self):
@@ -266,7 +273,7 @@ class HomeServer(object):
         return self.clock
 
     def get_datastore(self):
-        return self.datastore
+        return self.datastores.main
 
     def get_config(self):
         return self.config
@@ -308,6 +315,13 @@ class HomeServer(object):
     def build_simple_http_client(self):
         return SimpleHttpClient(self)
 
+    def build_proxied_http_client(self):
+        return SimpleHttpClient(
+            self,
+            http_proxy=os.getenv("http_proxy"),
+            https_proxy=os.getenv("HTTPS_PROXY"),
+        )
+
     def build_room_creation_handler(self):
         return RoomCreationHandler(self)
 
@@ -537,6 +551,9 @@ class HomeServer(object):
     def build_event_client_serializer(self):
         return EventClientSerializer(self)
 
+    def build_storage(self) -> Storage:
+        return Storage(self, self.datastores)
+
     def remove_pusher(self, app_id, push_key, user_id):
         return self.get_pusherpool().remove_pusher(app_id, push_key, user_id)
 
diff --git a/synapse/server.pyi b/synapse/server.pyi
index 16f8f6b573..b5e0b57095 100644
--- a/synapse/server.pyi
+++ b/synapse/server.pyi
@@ -12,6 +12,7 @@ import synapse.handlers.message
 import synapse.handlers.room
 import synapse.handlers.room_member
 import synapse.handlers.set_password
+import synapse.http.client
 import synapse.rest.media.v1.media_repository
 import synapse.server_notices.server_notices_manager
 import synapse.server_notices.server_notices_sender
@@ -38,8 +39,16 @@ class HomeServer(object):
         pass
     def get_state_resolution_handler(self) -> synapse.state.StateResolutionHandler:
         pass
+    def get_simple_http_client(self) -> synapse.http.client.SimpleHttpClient:
+        """Fetch an HTTP client implementation which doesn't do any blacklisting
+        or support any HTTP_PROXY settings"""
+        pass
+    def get_proxied_http_client(self) -> synapse.http.client.SimpleHttpClient:
+        """Fetch an HTTP client implementation which doesn't do any blacklisting
+        but does support HTTP_PROXY settings"""
+        pass
     def get_deactivate_account_handler(
-        self
+        self,
     ) -> synapse.handlers.deactivate_account.DeactivateAccountHandler:
         pass
     def get_room_creation_handler(self) -> synapse.handlers.room.RoomCreationHandler:
@@ -47,32 +56,32 @@ class HomeServer(object):
     def get_room_member_handler(self) -> synapse.handlers.room_member.RoomMemberHandler:
         pass
     def get_event_creation_handler(
-        self
+        self,
     ) -> synapse.handlers.message.EventCreationHandler:
         pass
     def get_set_password_handler(
-        self
+        self,
     ) -> synapse.handlers.set_password.SetPasswordHandler:
         pass
     def get_federation_sender(self) -> synapse.federation.sender.FederationSender:
         pass
     def get_federation_transport_client(
-        self
+        self,
     ) -> synapse.federation.transport.client.TransportLayerClient:
         pass
     def get_media_repository_resource(
-        self
+        self,
     ) -> synapse.rest.media.v1.media_repository.MediaRepositoryResource:
         pass
     def get_media_repository(
-        self
+        self,
     ) -> synapse.rest.media.v1.media_repository.MediaRepository:
         pass
     def get_server_notices_manager(
-        self
+        self,
     ) -> synapse.server_notices.server_notices_manager.ServerNoticesManager:
         pass
     def get_server_notices_sender(
-        self
+        self,
     ) -> synapse.server_notices.server_notices_sender.ServerNoticesSender:
         pass
diff --git a/synapse/server_notices/resource_limits_server_notices.py b/synapse/server_notices/resource_limits_server_notices.py
index c0e7f475c9..9fae2e0afe 100644
--- a/synapse/server_notices/resource_limits_server_notices.py
+++ b/synapse/server_notices/resource_limits_server_notices.py
@@ -83,7 +83,7 @@ class ResourceLimitsServerNotices(object):
         room_id = yield self._server_notices_manager.get_notice_room_for_user(user_id)
 
         if not room_id:
-            logger.warn("Failed to get server notices room")
+            logger.warning("Failed to get server notices room")
             return
 
         yield self._check_and_set_tags(user_id, room_id)
diff --git a/synapse/spam_checker_api/__init__.py b/synapse/spam_checker_api/__init__.py
new file mode 100644
index 0000000000..efcc10f808
--- /dev/null
+++ b/synapse/spam_checker_api/__init__.py
@@ -0,0 +1,51 @@
+# -*- coding: utf-8 -*-
+# Copyright 2019 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 logging
+
+from twisted.internet import defer
+
+from synapse.storage.state import StateFilter
+
+logger = logging.getLogger(__name__)
+
+
+class SpamCheckerApi(object):
+    """A proxy object that gets passed to spam checkers so they can get
+    access to rooms and other relevant information.
+    """
+
+    def __init__(self, hs):
+        self.hs = hs
+
+        self._store = hs.get_datastore()
+
+    @defer.inlineCallbacks
+    def get_state_events_in_room(self, room_id, types):
+        """Gets state events for the given room.
+
+        Args:
+            room_id (string): The room ID to get state events in.
+            types (tuple): The event type and state key (using None
+                to represent 'any') of the room state to acquire.
+
+        Returns:
+            twisted.internet.defer.Deferred[list(synapse.events.FrozenEvent)]:
+                The filtered state events in the room.
+        """
+        state_ids = yield self._store.get_filtered_current_state_ids(
+            room_id=room_id, state_filter=StateFilter.from_types(types)
+        )
+        state = yield self._store.get_events(state_ids.values())
+        return state.values()
diff --git a/synapse/state/__init__.py b/synapse/state/__init__.py
index dc9f5a9008..2c04ab1854 100644
--- a/synapse/state/__init__.py
+++ b/synapse/state/__init__.py
@@ -103,6 +103,7 @@ class StateHandler(object):
     def __init__(self, hs):
         self.clock = hs.get_clock()
         self.store = hs.get_datastore()
+        self.state_store = hs.get_storage().state
         self.hs = hs
         self._state_resolution_handler = hs.get_state_resolution_handler()
 
@@ -231,6 +232,9 @@ class StateHandler(object):
             # If this is an outlier, then we know it shouldn't have any current
             # state. Certainly store.get_current_state won't return any, and
             # persisting the event won't store the state group.
+
+            # FIXME: why do we populate current_state_ids? I thought the point was
+            # that we weren't supposed to have any state for outliers?
             if old_state:
                 prev_state_ids = {(s.type, s.state_key): s.event_id for s in old_state}
                 if event.is_state():
@@ -271,7 +275,7 @@ class StateHandler(object):
             else:
                 current_state_ids = prev_state_ids
 
-            state_group = yield self.store.store_state_group(
+            state_group = yield self.state_store.store_state_group(
                 event.event_id,
                 event.room_id,
                 prev_group=None,
@@ -321,7 +325,7 @@ class StateHandler(object):
                 delta_ids = dict(entry.delta_ids)
                 delta_ids[key] = event.event_id
 
-            state_group = yield self.store.store_state_group(
+            state_group = yield self.state_store.store_state_group(
                 event.event_id,
                 event.room_id,
                 prev_group=prev_group,
@@ -334,7 +338,7 @@ class StateHandler(object):
             delta_ids = entry.delta_ids
 
             if entry.state_group is None:
-                entry.state_group = yield self.store.store_state_group(
+                entry.state_group = yield self.state_store.store_state_group(
                     event.event_id,
                     event.room_id,
                     prev_group=entry.prev_group,
@@ -376,14 +380,16 @@ class StateHandler(object):
         # map from state group id to the state in that state group (where
         # 'state' is a map from state key to event id)
         # dict[int, dict[(str, str), str]]
-        state_groups_ids = yield self.store.get_state_groups_ids(room_id, event_ids)
+        state_groups_ids = yield self.state_store.get_state_groups_ids(
+            room_id, event_ids
+        )
 
         if len(state_groups_ids) == 0:
             return _StateCacheEntry(state={}, state_group=None)
         elif len(state_groups_ids) == 1:
             name, state_list = list(state_groups_ids.items()).pop()
 
-            prev_group, delta_ids = yield self.store.get_state_group_delta(name)
+            prev_group, delta_ids = yield self.state_store.get_state_group_delta(name)
 
             return _StateCacheEntry(
                 state=state_list,
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index a249ecd219..0a1a8cc1e5 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -27,7 +27,26 @@ data stores associated with them (e.g. the schema version tables), which are
 stored in `synapse.storage.schema`.
 """
 
-from synapse.storage.data_stores.main import DataStore  # noqa: F401
+from synapse.storage.data_stores import DataStores
+from synapse.storage.data_stores.main import DataStore
+from synapse.storage.persist_events import EventsPersistenceStorage
+from synapse.storage.state import StateGroupStorage
+
+__all__ = ["DataStores", "DataStore"]
+
+
+class Storage(object):
+    """The high level interfaces for talking to various storage layers.
+    """
+
+    def __init__(self, hs, stores: DataStores):
+        # We include the main data store here mainly so that we don't have to
+        # rewrite all the existing code to split it into high vs low level
+        # interfaces.
+        self.main = stores.main
+
+        self.persistence = EventsPersistenceStorage(hs, stores)
+        self.state = StateGroupStorage(hs, stores)
 
 
 def are_all_users_on_domain(txn, database_engine, domain):
diff --git a/synapse/storage/_base.py b/synapse/storage/_base.py
index f5906fcd54..1a2b7ebe25 100644
--- a/synapse/storage/_base.py
+++ b/synapse/storage/_base.py
@@ -494,7 +494,7 @@ class SQLBaseStore(object):
         exception_callbacks = []
 
         if LoggingContext.current_context() == LoggingContext.sentinel:
-            logger.warn("Starting db txn '%s' from sentinel context", desc)
+            logger.warning("Starting db txn '%s' from sentinel context", desc)
 
         try:
             result = yield self.runWithConnection(
@@ -532,7 +532,7 @@ class SQLBaseStore(object):
         """
         parent_context = LoggingContext.current_context()
         if parent_context == LoggingContext.sentinel:
-            logger.warn(
+            logger.warning(
                 "Starting db connection from sentinel context: metrics will be lost"
             )
             parent_context = None
@@ -719,7 +719,7 @@ class SQLBaseStore(object):
                     raise
 
                 # presumably we raced with another transaction: let's retry.
-                logger.warn(
+                logger.warning(
                     "IntegrityError when upserting into %s; retrying: %s", table, e
                 )
 
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
index 80b57a948c..37d469ffd7 100644
--- a/synapse/storage/background_updates.py
+++ b/synapse/storage/background_updates.py
@@ -94,13 +94,16 @@ class BackgroundUpdateStore(SQLBaseStore):
         self._all_done = False
 
     def start_doing_background_updates(self):
-        run_as_background_process("background_updates", self._run_background_updates)
+        run_as_background_process("background_updates", self.run_background_updates)
 
     @defer.inlineCallbacks
-    def _run_background_updates(self):
+    def run_background_updates(self, sleep=True):
         logger.info("Starting background schema updates")
         while True:
-            yield self.hs.get_clock().sleep(self.BACKGROUND_UPDATE_INTERVAL_MS / 1000.0)
+            if sleep:
+                yield self.hs.get_clock().sleep(
+                    self.BACKGROUND_UPDATE_INTERVAL_MS / 1000.0
+                )
 
             try:
                 result = yield self.do_next_background_update(
diff --git a/synapse/storage/data_stores/__init__.py b/synapse/storage/data_stores/__init__.py
index 56094078ed..cb184a98cc 100644
--- a/synapse/storage/data_stores/__init__.py
+++ b/synapse/storage/data_stores/__init__.py
@@ -12,3 +12,15 @@
 # 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.
+
+
+class DataStores(object):
+    """The various data stores.
+
+    These are low level interfaces to physical databases.
+    """
+
+    def __init__(self, main_store, db_conn, hs):
+        # Note we pass in the main store here as workers use a different main
+        # store.
+        self.main = main_store
diff --git a/synapse/storage/data_stores/main/__init__.py b/synapse/storage/data_stores/main/__init__.py
index b185ba0b3e..10c940df1e 100644
--- a/synapse/storage/data_stores/main/__init__.py
+++ b/synapse/storage/data_stores/main/__init__.py
@@ -139,7 +139,10 @@ class DataStore(
             db_conn, "public_room_list_stream", "stream_id"
         )
         self._device_list_id_gen = StreamIdGenerator(
-            db_conn, "device_lists_stream", "stream_id"
+            db_conn,
+            "device_lists_stream",
+            "stream_id",
+            extra_tables=[("user_signature_stream", "stream_id")],
         )
         self._cross_signing_id_gen = StreamIdGenerator(
             db_conn, "e2e_cross_signing_keys", "stream_id"
@@ -317,7 +320,7 @@ class DataStore(
             ) u
         """
         txn.execute(sql, (time_from,))
-        count, = txn.fetchone()
+        (count,) = txn.fetchone()
         return count
 
     def count_r30_users(self):
@@ -396,7 +399,7 @@ class DataStore(
 
             txn.execute(sql, (thirty_days_ago_in_secs, thirty_days_ago_in_secs))
 
-            count, = txn.fetchone()
+            (count,) = txn.fetchone()
             results["all"] = count
 
             return results
diff --git a/synapse/storage/data_stores/main/devices.py b/synapse/storage/data_stores/main/devices.py
index f7a3542348..71f62036c0 100644
--- a/synapse/storage/data_stores/main/devices.py
+++ b/synapse/storage/data_stores/main/devices.py
@@ -37,6 +37,7 @@ from synapse.storage._base import (
     make_in_list_sql_clause,
 )
 from synapse.storage.background_updates import BackgroundUpdateStore
+from synapse.types import get_verify_key_from_cross_signing_key
 from synapse.util import batch_iter
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks, cachedList
 
@@ -90,13 +91,18 @@ class DeviceWorkerStore(SQLBaseStore):
 
     @trace
     @defer.inlineCallbacks
-    def get_devices_by_remote(self, destination, from_stream_id, limit):
-        """Get stream of updates to send to remote servers
+    def get_device_updates_by_remote(self, destination, from_stream_id, limit):
+        """Get a stream of device updates to send to the given remote server.
 
+        Args:
+            destination (str): The host the device updates are intended for
+            from_stream_id (int): The minimum stream_id to filter updates by, exclusive
+            limit (int): Maximum number of device updates to return
         Returns:
-            Deferred[tuple[int, list[dict]]]:
+            Deferred[tuple[int, list[tuple[string,dict]]]]:
                 current stream id (ie, the stream id of the last update included in the
-                response), and the list of updates
+                response), and the list of updates, where each update is a pair of EDU
+                type and EDU contents
         """
         now_stream_id = self._device_list_id_gen.get_current_token()
 
@@ -117,8 +123,8 @@ class DeviceWorkerStore(SQLBaseStore):
         # stream_id; the rationale being that such a large device list update
         # is likely an error.
         updates = yield self.runInteraction(
-            "get_devices_by_remote",
-            self._get_devices_by_remote_txn,
+            "get_device_updates_by_remote",
+            self._get_device_updates_by_remote_txn,
             destination,
             from_stream_id,
             now_stream_id,
@@ -129,6 +135,37 @@ class DeviceWorkerStore(SQLBaseStore):
         if not updates:
             return now_stream_id, []
 
+        # 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)
+        master_key_by_user = {}
+        self_signing_key_by_user = {}
+        for user in users:
+            cross_signing_key = yield self.get_e2e_cross_signing_key(user, "master")
+            if cross_signing_key:
+                key_id, verify_key = get_verify_key_from_cross_signing_key(
+                    cross_signing_key
+                )
+                # verify_key is a VerifyKey from signedjson, which uses
+                # .version to denote the portion of the key ID after the
+                # algorithm and colon, which is the device ID
+                master_key_by_user[user] = {
+                    "key_info": cross_signing_key,
+                    "device_id": verify_key.version,
+                }
+
+            cross_signing_key = yield self.get_e2e_cross_signing_key(
+                user, "self_signing"
+            )
+            if cross_signing_key:
+                key_id, verify_key = get_verify_key_from_cross_signing_key(
+                    cross_signing_key
+                )
+                self_signing_key_by_user[user] = {
+                    "key_info": cross_signing_key,
+                    "device_id": verify_key.version,
+                }
+
         # if we have exceeded the limit, we need to exclude any results with the
         # same stream_id as the last row.
         if len(updates) > limit:
@@ -153,20 +190,33 @@ class DeviceWorkerStore(SQLBaseStore):
         # context which created the Edu.
 
         query_map = {}
-        for update in updates:
-            if stream_id_cutoff is not None and update[2] >= stream_id_cutoff:
+        cross_signing_keys_by_user = {}
+        for user_id, device_id, update_stream_id, update_context in updates:
+            if stream_id_cutoff is not None and update_stream_id >= stream_id_cutoff:
                 # Stop processing updates
                 break
 
-            key = (update[0], update[1])
-
-            update_context = update[3]
-            update_stream_id = update[2]
+            if (
+                user_id in master_key_by_user
+                and device_id == master_key_by_user[user_id]["device_id"]
+            ):
+                result = cross_signing_keys_by_user.setdefault(user_id, {})
+                result["master_key"] = master_key_by_user[user_id]["key_info"]
+            elif (
+                user_id in self_signing_key_by_user
+                and device_id == self_signing_key_by_user[user_id]["device_id"]
+            ):
+                result = cross_signing_keys_by_user.setdefault(user_id, {})
+                result["self_signing_key"] = self_signing_key_by_user[user_id][
+                    "key_info"
+                ]
+            else:
+                key = (user_id, device_id)
 
-            previous_update_stream_id, _ = query_map.get(key, (0, None))
+                previous_update_stream_id, _ = query_map.get(key, (0, None))
 
-            if update_stream_id > previous_update_stream_id:
-                query_map[key] = (update_stream_id, update_context)
+                if update_stream_id > previous_update_stream_id:
+                    query_map[key] = (update_stream_id, update_context)
 
         # If we didn't find any updates with a stream_id lower than the cutoff, it
         # means that there are more than limit updates all of which have the same
@@ -176,16 +226,22 @@ class DeviceWorkerStore(SQLBaseStore):
         # devices, in which case E2E isn't going to work well anyway. We'll just
         # skip that stream_id and return an empty list, and continue with the next
         # stream_id next time.
-        if not query_map:
+        if not query_map and not cross_signing_keys_by_user:
             return stream_id_cutoff, []
 
         results = yield self._get_device_update_edus_by_remote(
             destination, from_stream_id, query_map
         )
 
+        # add the updated cross-signing keys to the results list
+        for user_id, result in iteritems(cross_signing_keys_by_user):
+            result["user_id"] = user_id
+            # FIXME: switch to m.signing_key_update when MSC1756 is merged into the spec
+            results.append(("org.matrix.signing_key_update", result))
+
         return now_stream_id, results
 
-    def _get_devices_by_remote_txn(
+    def _get_device_updates_by_remote_txn(
         self, txn, destination, from_stream_id, now_stream_id, limit
     ):
         """Return device update information for a given remote destination
@@ -200,6 +256,7 @@ class DeviceWorkerStore(SQLBaseStore):
         Returns:
             List: List of device updates
         """
+        # get the list of device updates that need to be sent
         sql = """
             SELECT user_id, device_id, stream_id, opentracing_context FROM device_lists_outbound_pokes
             WHERE destination = ? AND ? < stream_id AND stream_id <= ? AND sent = ?
@@ -225,12 +282,16 @@ class DeviceWorkerStore(SQLBaseStore):
             List[Dict]: List of objects representing an device update EDU
 
         """
-        devices = yield self.runInteraction(
-            "_get_e2e_device_keys_txn",
-            self._get_e2e_device_keys_txn,
-            query_map.keys(),
-            include_all_devices=True,
-            include_deleted_devices=True,
+        devices = (
+            yield self.runInteraction(
+                "_get_e2e_device_keys_txn",
+                self._get_e2e_device_keys_txn,
+                query_map.keys(),
+                include_all_devices=True,
+                include_deleted_devices=True,
+            )
+            if query_map
+            else {}
         )
 
         results = []
@@ -262,7 +323,7 @@ class DeviceWorkerStore(SQLBaseStore):
                 else:
                     result["deleted"] = True
 
-                results.append(result)
+                results.append(("m.device_list_update", result))
 
         return results
 
diff --git a/synapse/storage/data_stores/main/e2e_room_keys.py b/synapse/storage/data_stores/main/e2e_room_keys.py
index ef88e79293..1cbbae5b63 100644
--- a/synapse/storage/data_stores/main/e2e_room_keys.py
+++ b/synapse/storage/data_stores/main/e2e_room_keys.py
@@ -321,9 +321,17 @@ class EndToEndRoomKeyStore(SQLBaseStore):
         def _delete_e2e_room_keys_version_txn(txn):
             if version is None:
                 this_version = self._get_current_version(txn, user_id)
+                if this_version is None:
+                    raise StoreError(404, "No current backup version")
             else:
                 this_version = version
 
+            self._simple_delete_txn(
+                txn,
+                table="e2e_room_keys",
+                keyvalues={"user_id": user_id, "version": this_version},
+            )
+
             return self._simple_update_one_txn(
                 txn,
                 table="e2e_room_keys_versions",
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 a0bc6f2d18..073412a78d 100644
--- a/synapse/storage/data_stores/main/end_to_end_keys.py
+++ b/synapse/storage/data_stores/main/end_to_end_keys.py
@@ -315,6 +315,30 @@ class EndToEndKeyWorkerStore(SQLBaseStore):
             from_user_id,
         )
 
+    def get_all_user_signature_changes_for_remotes(self, from_key, to_key):
+        """Return a list of changes from the user signature stream to notify remotes.
+        Note that the user signature stream represents when a user signs their
+        device with their user-signing key, which is not published to other
+        users or servers, so no `destination` is needed in the returned
+        list. However, this is needed to poke workers.
+
+        Args:
+            from_key (int): the stream ID to start at (exclusive)
+            to_key (int): the stream ID to end at (inclusive)
+
+        Returns:
+            Deferred[list[(int,str)]] a list of `(stream_id, user_id)`
+        """
+        sql = """
+            SELECT MAX(stream_id) AS stream_id, from_user_id AS user_id
+            FROM user_signature_stream
+            WHERE ? < stream_id AND stream_id <= ?
+            GROUP BY user_id
+        """
+        return self._execute(
+            "get_all_user_signature_changes_for_remotes", None, sql, from_key, to_key
+        )
+
 
 class EndToEndKeyStore(EndToEndKeyWorkerStore, SQLBaseStore):
     def set_e2e_device_keys(self, user_id, device_id, time_now, device_keys):
diff --git a/synapse/storage/data_stores/main/event_federation.py b/synapse/storage/data_stores/main/event_federation.py
index a470a48e0f..90bef0cd2c 100644
--- a/synapse/storage/data_stores/main/event_federation.py
+++ b/synapse/storage/data_stores/main/event_federation.py
@@ -364,9 +364,7 @@ class EventFederationWorkerStore(EventsWorkerStore, SignatureWorkerStore, SQLBas
         )
 
     def _get_backfill_events(self, txn, room_id, event_list, limit):
-        logger.debug(
-            "_get_backfill_events: %s, %s, %s", room_id, repr(event_list), limit
-        )
+        logger.debug("_get_backfill_events: %s, %r, %s", room_id, event_list, limit)
 
         event_results = set()
 
diff --git a/synapse/storage/data_stores/main/event_push_actions.py b/synapse/storage/data_stores/main/event_push_actions.py
index 22025effbc..04ce21ac66 100644
--- a/synapse/storage/data_stores/main/event_push_actions.py
+++ b/synapse/storage/data_stores/main/event_push_actions.py
@@ -863,7 +863,7 @@ class EventPushActionsStore(EventPushActionsWorkerStore):
         )
         stream_row = txn.fetchone()
         if stream_row:
-            offset_stream_ordering, = stream_row
+            (offset_stream_ordering,) = stream_row
             rotate_to_stream_ordering = min(
                 self.stream_ordering_day_ago, offset_stream_ordering
             )
diff --git a/synapse/storage/data_stores/main/events.py b/synapse/storage/data_stores/main/events.py
index 03b5111c5d..301f8ea128 100644
--- a/synapse/storage/data_stores/main/events.py
+++ b/synapse/storage/data_stores/main/events.py
@@ -17,28 +17,26 @@
 
 import itertools
 import logging
-from collections import Counter as c_counter, OrderedDict, deque, namedtuple
+from collections import Counter as c_counter, OrderedDict, namedtuple
 from functools import wraps
 
 from six import iteritems, text_type
 from six.moves import range
 
 from canonicaljson import json
-from prometheus_client import Counter, Histogram
+from prometheus_client import Counter
 
 from twisted.internet import defer
 
 import synapse.metrics
-from synapse.api.constants import EventTypes
+from synapse.api.constants import EventContentFields, EventTypes
 from synapse.api.errors import SynapseError
 from synapse.events import EventBase  # noqa: F401
 from synapse.events.snapshot import EventContext  # noqa: F401
 from synapse.events.utils import prune_event_dict
-from synapse.logging.context import PreserveLoggingContext, make_deferred_yieldable
 from synapse.logging.utils import log_function
 from synapse.metrics import BucketCollector
 from synapse.metrics.background_process_metrics import run_as_background_process
-from synapse.state import StateResolutionStore
 from synapse.storage._base import make_in_list_sql_clause
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.storage.data_stores.main.event_federation import EventFederationStore
@@ -46,10 +44,8 @@ from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
 from synapse.storage.data_stores.main.state import StateGroupWorkerStore
 from synapse.types import RoomStreamToken, get_domain_from_id
 from synapse.util import batch_iter
-from synapse.util.async_helpers import ObservableDeferred
 from synapse.util.caches.descriptors import cached, cachedInlineCallbacks
 from synapse.util.frozenutils import frozendict_json_encoder
-from synapse.util.metrics import Measure
 
 logger = logging.getLogger(__name__)
 
@@ -60,37 +56,6 @@ event_counter = Counter(
     ["type", "origin_type", "origin_entity"],
 )
 
-# The number of times we are recalculating the current state
-state_delta_counter = Counter("synapse_storage_events_state_delta", "")
-
-# The number of times we are recalculating state when there is only a
-# single forward extremity
-state_delta_single_event_counter = Counter(
-    "synapse_storage_events_state_delta_single_event", ""
-)
-
-# The number of times we are reculating state when we could have resonably
-# calculated the delta when we calculated the state for an event we were
-# persisting.
-state_delta_reuse_delta_counter = Counter(
-    "synapse_storage_events_state_delta_reuse_delta", ""
-)
-
-# The number of forward extremities for each new event.
-forward_extremities_counter = Histogram(
-    "synapse_storage_events_forward_extremities_persisted",
-    "Number of forward extremities for each new event",
-    buckets=(1, 2, 3, 5, 7, 10, 15, 20, 50, 100, 200, 500, "+Inf"),
-)
-
-# The number of stale forward extremities for each new event. Stale extremities
-# are those that were in the previous set of extremities as well as the new.
-stale_forward_extremities_counter = Histogram(
-    "synapse_storage_events_stale_forward_extremities_persisted",
-    "Number of unchanged forward extremities for each new event",
-    buckets=(0, 1, 2, 3, 5, 7, 10, 15, 20, 50, 100, 200, 500, "+Inf"),
-)
-
 
 def encode_json(json_object):
     """
@@ -102,110 +67,6 @@ def encode_json(json_object):
     return out
 
 
-class _EventPeristenceQueue(object):
-    """Queues up events so that they can be persisted in bulk with only one
-    concurrent transaction per room.
-    """
-
-    _EventPersistQueueItem = namedtuple(
-        "_EventPersistQueueItem", ("events_and_contexts", "backfilled", "deferred")
-    )
-
-    def __init__(self):
-        self._event_persist_queues = {}
-        self._currently_persisting_rooms = set()
-
-    def add_to_queue(self, room_id, events_and_contexts, backfilled):
-        """Add events to the queue, with the given persist_event options.
-
-        NB: due to the normal usage pattern of this method, it does *not*
-        follow the synapse logcontext rules, and leaves the logcontext in
-        place whether or not the returned deferred is ready.
-
-        Args:
-            room_id (str):
-            events_and_contexts (list[(EventBase, EventContext)]):
-            backfilled (bool):
-
-        Returns:
-            defer.Deferred: a deferred which will resolve once the events are
-                persisted. Runs its callbacks *without* a logcontext.
-        """
-        queue = self._event_persist_queues.setdefault(room_id, deque())
-        if queue:
-            # if the last item in the queue has the same `backfilled` setting,
-            # we can just add these new events to that item.
-            end_item = queue[-1]
-            if end_item.backfilled == backfilled:
-                end_item.events_and_contexts.extend(events_and_contexts)
-                return end_item.deferred.observe()
-
-        deferred = ObservableDeferred(defer.Deferred(), consumeErrors=True)
-
-        queue.append(
-            self._EventPersistQueueItem(
-                events_and_contexts=events_and_contexts,
-                backfilled=backfilled,
-                deferred=deferred,
-            )
-        )
-
-        return deferred.observe()
-
-    def handle_queue(self, room_id, per_item_callback):
-        """Attempts to handle the queue for a room if not already being handled.
-
-        The given callback will be invoked with for each item in the queue,
-        of type _EventPersistQueueItem. The per_item_callback will continuously
-        be called with new items, unless the queue becomnes empty. The return
-        value of the function will be given to the deferreds waiting on the item,
-        exceptions will be passed to the deferreds as well.
-
-        This function should therefore be called whenever anything is added
-        to the queue.
-
-        If another callback is currently handling the queue then it will not be
-        invoked.
-        """
-
-        if room_id in self._currently_persisting_rooms:
-            return
-
-        self._currently_persisting_rooms.add(room_id)
-
-        @defer.inlineCallbacks
-        def handle_queue_loop():
-            try:
-                queue = self._get_drainining_queue(room_id)
-                for item in queue:
-                    try:
-                        ret = yield per_item_callback(item)
-                    except Exception:
-                        with PreserveLoggingContext():
-                            item.deferred.errback()
-                    else:
-                        with PreserveLoggingContext():
-                            item.deferred.callback(ret)
-            finally:
-                queue = self._event_persist_queues.pop(room_id, None)
-                if queue:
-                    self._event_persist_queues[room_id] = queue
-                self._currently_persisting_rooms.discard(room_id)
-
-        # set handle_queue_loop off in the background
-        run_as_background_process("persist_events", handle_queue_loop)
-
-    def _get_drainining_queue(self, room_id):
-        queue = self._event_persist_queues.setdefault(room_id, deque())
-
-        try:
-            while True:
-                yield queue.popleft()
-        except IndexError:
-            # Queue has been drained.
-            pass
-
-
 _EventCacheEntry = namedtuple("_EventCacheEntry", ("event", "redacted_event"))
 
 
@@ -221,7 +82,7 @@ def _retry_on_integrity_error(func):
     @defer.inlineCallbacks
     def f(self, *args, **kwargs):
         try:
-            res = yield func(self, *args, **kwargs)
+            res = yield func(self, *args, delete_existing=False, **kwargs)
         except self.database_engine.module.IntegrityError:
             logger.exception("IntegrityError, retrying.")
             res = yield func(self, *args, delete_existing=True, **kwargs)
@@ -241,9 +102,6 @@ class EventsStore(
     def __init__(self, db_conn, hs):
         super(EventsStore, self).__init__(db_conn, hs)
 
-        self._event_persist_queue = _EventPeristenceQueue()
-        self._state_resolution_handler = hs.get_state_resolution_handler()
-
         # Collect metrics on the number of forward extremities that exist.
         # Counter of number of extremities to count
         self._current_forward_extremities_amount = c_counter()
@@ -286,340 +144,106 @@ class EventsStore(
         res = yield self.runInteraction("read_forward_extremities", fetch)
         self._current_forward_extremities_amount = c_counter(list(x[0] for x in res))
 
-    @defer.inlineCallbacks
-    def persist_events(self, events_and_contexts, backfilled=False):
-        """
-        Write events to the database
-        Args:
-            events_and_contexts: list of tuples of (event, context)
-            backfilled (bool): Whether the results are retrieved from federation
-                via backfill or not. Used to determine if they're "new" events
-                which might update the current state etc.
-
-        Returns:
-            Deferred[int]: the stream ordering of the latest persisted event
-        """
-        partitioned = {}
-        for event, ctx in events_and_contexts:
-            partitioned.setdefault(event.room_id, []).append((event, ctx))
-
-        deferreds = []
-        for room_id, evs_ctxs in iteritems(partitioned):
-            d = self._event_persist_queue.add_to_queue(
-                room_id, evs_ctxs, backfilled=backfilled
-            )
-            deferreds.append(d)
-
-        for room_id in partitioned:
-            self._maybe_start_persisting(room_id)
-
-        yield make_deferred_yieldable(
-            defer.gatherResults(deferreds, consumeErrors=True)
-        )
-
-        max_persisted_id = yield self._stream_id_gen.get_current_token()
-
-        return max_persisted_id
-
-    @defer.inlineCallbacks
-    @log_function
-    def persist_event(self, event, context, backfilled=False):
-        """
-
-        Args:
-            event (EventBase):
-            context (EventContext):
-            backfilled (bool):
-
-        Returns:
-            Deferred: resolves to (int, int): the stream ordering of ``event``,
-            and the stream ordering of the latest persisted event
-        """
-        deferred = self._event_persist_queue.add_to_queue(
-            event.room_id, [(event, context)], backfilled=backfilled
-        )
-
-        self._maybe_start_persisting(event.room_id)
-
-        yield make_deferred_yieldable(deferred)
-
-        max_persisted_id = yield self._stream_id_gen.get_current_token()
-        return (event.internal_metadata.stream_ordering, max_persisted_id)
-
-    def _maybe_start_persisting(self, room_id):
-        @defer.inlineCallbacks
-        def persisting_queue(item):
-            with Measure(self._clock, "persist_events"):
-                yield self._persist_events(
-                    item.events_and_contexts, backfilled=item.backfilled
-                )
-
-        self._event_persist_queue.handle_queue(room_id, persisting_queue)
-
     @_retry_on_integrity_error
     @defer.inlineCallbacks
-    def _persist_events(
-        self, events_and_contexts, backfilled=False, delete_existing=False
+    def _persist_events_and_state_updates(
+        self,
+        events_and_contexts,
+        current_state_for_room,
+        state_delta_for_room,
+        new_forward_extremeties,
+        backfilled=False,
+        delete_existing=False,
     ):
-        """Persist events to db
+        """Persist a set of events alongside updates to the current state and
+        forward extremities tables.
 
         Args:
             events_and_contexts (list[(EventBase, EventContext)]):
-            backfilled (bool):
+            current_state_for_room (dict[str, dict]): Map from room_id to the
+                current state of the room based on forward extremities
+            state_delta_for_room (dict[str, tuple]): Map from room_id to tuple
+                of `(to_delete, to_insert)` where to_delete is a list
+                of type/state keys to remove from current state, and to_insert
+                is a map (type,key)->event_id giving the state delta in each
+                room.
+            new_forward_extremities (dict[str, list[str]]): Map from room_id
+                to list of event IDs that are the new forward extremities of
+                the room.
+            backfilled (bool)
             delete_existing (bool):
 
         Returns:
             Deferred: resolves when the events have been persisted
         """
-        if not events_and_contexts:
-            return
-
-        chunks = [
-            events_and_contexts[x : x + 100]
-            for x in range(0, len(events_and_contexts), 100)
-        ]
 
-        for chunk in chunks:
-            # We can't easily parallelize these since different chunks
-            # might contain the same event. :(
-
-            # NB: Assumes that we are only persisting events for one room
-            # at a time.
-
-            # map room_id->list[event_ids] giving the new forward
-            # extremities in each room
-            new_forward_extremeties = {}
+        # We want to calculate the stream orderings as late as possible, as
+        # we only notify after all events with a lesser stream ordering have
+        # been persisted. I.e. if we spend 10s inside the with block then
+        # that will delay all subsequent events from being notified about.
+        # Hence why we do it down here rather than wrapping the entire
+        # function.
+        #
+        # Its safe to do this after calculating the state deltas etc as we
+        # only need to protect the *persistence* of the events. This is to
+        # ensure that queries of the form "fetch events since X" don't
+        # return events and stream positions after events that are still in
+        # flight, as otherwise subsequent requests "fetch event since Y"
+        # will not return those events.
+        #
+        # Note: Multiple instances of this function cannot be in flight at
+        # the same time for the same room.
+        if backfilled:
+            stream_ordering_manager = self._backfill_id_gen.get_next_mult(
+                len(events_and_contexts)
+            )
+        else:
+            stream_ordering_manager = self._stream_id_gen.get_next_mult(
+                len(events_and_contexts)
+            )
 
-            # map room_id->(type,state_key)->event_id tracking the full
-            # state in each room after adding these events.
-            # This is simply used to prefill the get_current_state_ids
-            # cache
-            current_state_for_room = {}
+        with stream_ordering_manager as stream_orderings:
+            for (event, context), stream in zip(events_and_contexts, stream_orderings):
+                event.internal_metadata.stream_ordering = stream
 
-            # map room_id->(to_delete, to_insert) where to_delete is a list
-            # of type/state keys to remove from current state, and to_insert
-            # is a map (type,key)->event_id giving the state delta in each
-            # room
-            state_delta_for_room = {}
+            yield self.runInteraction(
+                "persist_events",
+                self._persist_events_txn,
+                events_and_contexts=events_and_contexts,
+                backfilled=backfilled,
+                delete_existing=delete_existing,
+                state_delta_for_room=state_delta_for_room,
+                new_forward_extremeties=new_forward_extremeties,
+            )
+            persist_event_counter.inc(len(events_and_contexts))
 
             if not backfilled:
-                with Measure(self._clock, "_calculate_state_and_extrem"):
-                    # Work out the new "current state" for each room.
-                    # We do this by working out what the new extremities are and then
-                    # calculating the state from that.
-                    events_by_room = {}
-                    for event, context in chunk:
-                        events_by_room.setdefault(event.room_id, []).append(
-                            (event, context)
-                        )
-
-                    for room_id, ev_ctx_rm in iteritems(events_by_room):
-                        latest_event_ids = yield self.get_latest_event_ids_in_room(
-                            room_id
-                        )
-                        new_latest_event_ids = yield self._calculate_new_extremities(
-                            room_id, ev_ctx_rm, latest_event_ids
-                        )
-
-                        latest_event_ids = set(latest_event_ids)
-                        if new_latest_event_ids == latest_event_ids:
-                            # No change in extremities, so no change in state
-                            continue
-
-                        # there should always be at least one forward extremity.
-                        # (except during the initial persistence of the send_join
-                        # results, in which case there will be no existing
-                        # extremities, so we'll `continue` above and skip this bit.)
-                        assert new_latest_event_ids, "No forward extremities left!"
-
-                        new_forward_extremeties[room_id] = new_latest_event_ids
-
-                        len_1 = (
-                            len(latest_event_ids) == 1
-                            and len(new_latest_event_ids) == 1
-                        )
-                        if len_1:
-                            all_single_prev_not_state = all(
-                                len(event.prev_event_ids()) == 1
-                                and not event.is_state()
-                                for event, ctx in ev_ctx_rm
-                            )
-                            # Don't bother calculating state if they're just
-                            # a long chain of single ancestor non-state events.
-                            if all_single_prev_not_state:
-                                continue
-
-                        state_delta_counter.inc()
-                        if len(new_latest_event_ids) == 1:
-                            state_delta_single_event_counter.inc()
-
-                            # This is a fairly handwavey check to see if we could
-                            # have guessed what the delta would have been when
-                            # processing one of these events.
-                            # What we're interested in is if the latest extremities
-                            # were the same when we created the event as they are
-                            # now. When this server creates a new event (as opposed
-                            # to receiving it over federation) it will use the
-                            # forward extremities as the prev_events, so we can
-                            # guess this by looking at the prev_events and checking
-                            # if they match the current forward extremities.
-                            for ev, _ in ev_ctx_rm:
-                                prev_event_ids = set(ev.prev_event_ids())
-                                if latest_event_ids == prev_event_ids:
-                                    state_delta_reuse_delta_counter.inc()
-                                    break
-
-                        logger.info("Calculating state delta for room %s", room_id)
-                        with Measure(
-                            self._clock, "persist_events.get_new_state_after_events"
-                        ):
-                            res = yield self._get_new_state_after_events(
-                                room_id,
-                                ev_ctx_rm,
-                                latest_event_ids,
-                                new_latest_event_ids,
-                            )
-                            current_state, delta_ids = res
-
-                        # If either are not None then there has been a change,
-                        # and we need to work out the delta (or use that
-                        # given)
-                        if delta_ids is not None:
-                            # If there is a delta we know that we've
-                            # only added or replaced state, never
-                            # removed keys entirely.
-                            state_delta_for_room[room_id] = ([], delta_ids)
-                        elif current_state is not None:
-                            with Measure(
-                                self._clock, "persist_events.calculate_state_delta"
-                            ):
-                                delta = yield self._calculate_state_delta(
-                                    room_id, current_state
-                                )
-                            state_delta_for_room[room_id] = delta
-
-                        # If we have the current_state then lets prefill
-                        # the cache with it.
-                        if current_state is not None:
-                            current_state_for_room[room_id] = current_state
-
-            # We want to calculate the stream orderings as late as possible, as
-            # we only notify after all events with a lesser stream ordering have
-            # been persisted. I.e. if we spend 10s inside the with block then
-            # that will delay all subsequent events from being notified about.
-            # Hence why we do it down here rather than wrapping the entire
-            # function.
-            #
-            # Its safe to do this after calculating the state deltas etc as we
-            # only need to protect the *persistence* of the events. This is to
-            # ensure that queries of the form "fetch events since X" don't
-            # return events and stream positions after events that are still in
-            # flight, as otherwise subsequent requests "fetch event since Y"
-            # will not return those events.
-            #
-            # Note: Multiple instances of this function cannot be in flight at
-            # the same time for the same room.
-            if backfilled:
-                stream_ordering_manager = self._backfill_id_gen.get_next_mult(
-                    len(chunk)
+                # backfilled events have negative stream orderings, so we don't
+                # want to set the event_persisted_position to that.
+                synapse.metrics.event_persisted_position.set(
+                    events_and_contexts[-1][0].internal_metadata.stream_ordering
                 )
-            else:
-                stream_ordering_manager = self._stream_id_gen.get_next_mult(len(chunk))
-
-            with stream_ordering_manager as stream_orderings:
-                for (event, context), stream in zip(chunk, stream_orderings):
-                    event.internal_metadata.stream_ordering = stream
-
-                yield self.runInteraction(
-                    "persist_events",
-                    self._persist_events_txn,
-                    events_and_contexts=chunk,
-                    backfilled=backfilled,
-                    delete_existing=delete_existing,
-                    state_delta_for_room=state_delta_for_room,
-                    new_forward_extremeties=new_forward_extremeties,
-                )
-                persist_event_counter.inc(len(chunk))
-
-                if not backfilled:
-                    # backfilled events have negative stream orderings, so we don't
-                    # want to set the event_persisted_position to that.
-                    synapse.metrics.event_persisted_position.set(
-                        chunk[-1][0].internal_metadata.stream_ordering
-                    )
-
-                for event, context in chunk:
-                    if context.app_service:
-                        origin_type = "local"
-                        origin_entity = context.app_service.id
-                    elif self.hs.is_mine_id(event.sender):
-                        origin_type = "local"
-                        origin_entity = "*client*"
-                    else:
-                        origin_type = "remote"
-                        origin_entity = get_domain_from_id(event.sender)
-
-                    event_counter.labels(event.type, origin_type, origin_entity).inc()
-
-                for room_id, new_state in iteritems(current_state_for_room):
-                    self.get_current_state_ids.prefill((room_id,), new_state)
-
-                for room_id, latest_event_ids in iteritems(new_forward_extremeties):
-                    self.get_latest_event_ids_in_room.prefill(
-                        (room_id,), list(latest_event_ids)
-                    )
-
-    @defer.inlineCallbacks
-    def _calculate_new_extremities(self, room_id, event_contexts, latest_event_ids):
-        """Calculates the new forward extremities for a room given events to
-        persist.
-
-        Assumes that we are only persisting events for one room at a time.
-        """
-
-        # we're only interested in new events which aren't outliers and which aren't
-        # being rejected.
-        new_events = [
-            event
-            for event, ctx in event_contexts
-            if not event.internal_metadata.is_outlier()
-            and not ctx.rejected
-            and not event.internal_metadata.is_soft_failed()
-        ]
-
-        latest_event_ids = set(latest_event_ids)
 
-        # start with the existing forward extremities
-        result = set(latest_event_ids)
-
-        # add all the new events to the list
-        result.update(event.event_id for event in new_events)
-
-        # Now remove all events which are prev_events of any of the new events
-        result.difference_update(
-            e_id for event in new_events for e_id in event.prev_event_ids()
-        )
-
-        # Remove any events which are prev_events of any existing events.
-        existing_prevs = yield self._get_events_which_are_prevs(result)
-        result.difference_update(existing_prevs)
+            for event, context in events_and_contexts:
+                if context.app_service:
+                    origin_type = "local"
+                    origin_entity = context.app_service.id
+                elif self.hs.is_mine_id(event.sender):
+                    origin_type = "local"
+                    origin_entity = "*client*"
+                else:
+                    origin_type = "remote"
+                    origin_entity = get_domain_from_id(event.sender)
 
-        # Finally handle the case where the new events have soft-failed prev
-        # events. If they do we need to remove them and their prev events,
-        # otherwise we end up with dangling extremities.
-        existing_prevs = yield self._get_prevs_before_rejected(
-            e_id for event in new_events for e_id in event.prev_event_ids()
-        )
-        result.difference_update(existing_prevs)
+                event_counter.labels(event.type, origin_type, origin_entity).inc()
 
-        # We only update metrics for events that change forward extremities
-        # (e.g. we ignore backfill/outliers/etc)
-        if result != latest_event_ids:
-            forward_extremities_counter.observe(len(result))
-            stale = latest_event_ids & result
-            stale_forward_extremities_counter.observe(len(stale))
+            for room_id, new_state in iteritems(current_state_for_room):
+                self.get_current_state_ids.prefill((room_id,), new_state)
 
-        return result
+            for room_id, latest_event_ids in iteritems(new_forward_extremeties):
+                self.get_latest_event_ids_in_room.prefill(
+                    (room_id,), list(latest_event_ids)
+                )
 
     @defer.inlineCallbacks
     def _get_events_which_are_prevs(self, event_ids):
@@ -725,188 +349,6 @@ class EventsStore(
 
         return existing_prevs
 
-    @defer.inlineCallbacks
-    def _get_new_state_after_events(
-        self, room_id, events_context, old_latest_event_ids, new_latest_event_ids
-    ):
-        """Calculate the current state dict after adding some new events to
-        a room
-
-        Args:
-            room_id (str):
-                room to which the events are being added. Used for logging etc
-
-            events_context (list[(EventBase, EventContext)]):
-                events and contexts which are being added to the room
-
-            old_latest_event_ids (iterable[str]):
-                the old forward extremities for the room.
-
-            new_latest_event_ids (iterable[str]):
-                the new forward extremities for the room.
-
-        Returns:
-            Deferred[tuple[dict[(str,str), str]|None, dict[(str,str), str]|None]]:
-            Returns a tuple of two state maps, the first being the full new current
-            state and the second being the delta to the existing current state.
-            If both are None then there has been no change.
-
-            If there has been a change then we only return the delta if its
-            already been calculated. Conversely if we do know the delta then
-            the new current state is only returned if we've already calculated
-            it.
-        """
-        # map from state_group to ((type, key) -> event_id) state map
-        state_groups_map = {}
-
-        # Map from (prev state group, new state group) -> delta state dict
-        state_group_deltas = {}
-
-        for ev, ctx in events_context:
-            if ctx.state_group is None:
-                # This should only happen for outlier events.
-                if not ev.internal_metadata.is_outlier():
-                    raise Exception(
-                        "Context for new event %s has no state "
-                        "group" % (ev.event_id,)
-                    )
-                continue
-
-            if ctx.state_group in state_groups_map:
-                continue
-
-            # We're only interested in pulling out state that has already
-            # been cached in the context. We'll pull stuff out of the DB later
-            # if necessary.
-            current_state_ids = ctx.get_cached_current_state_ids()
-            if current_state_ids is not None:
-                state_groups_map[ctx.state_group] = current_state_ids
-
-            if ctx.prev_group:
-                state_group_deltas[(ctx.prev_group, ctx.state_group)] = ctx.delta_ids
-
-        # We need to map the event_ids to their state groups. First, let's
-        # check if the event is one we're persisting, in which case we can
-        # pull the state group from its context.
-        # Otherwise we need to pull the state group from the database.
-
-        # Set of events we need to fetch groups for. (We know none of the old
-        # extremities are going to be in events_context).
-        missing_event_ids = set(old_latest_event_ids)
-
-        event_id_to_state_group = {}
-        for event_id in new_latest_event_ids:
-            # First search in the list of new events we're adding.
-            for ev, ctx in events_context:
-                if event_id == ev.event_id and ctx.state_group is not None:
-                    event_id_to_state_group[event_id] = ctx.state_group
-                    break
-            else:
-                # If we couldn't find it, then we'll need to pull
-                # the state from the database
-                missing_event_ids.add(event_id)
-
-        if missing_event_ids:
-            # Now pull out the state groups for any missing events from DB
-            event_to_groups = yield self._get_state_group_for_events(missing_event_ids)
-            event_id_to_state_group.update(event_to_groups)
-
-        # State groups of old_latest_event_ids
-        old_state_groups = set(
-            event_id_to_state_group[evid] for evid in old_latest_event_ids
-        )
-
-        # State groups of new_latest_event_ids
-        new_state_groups = set(
-            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.
-        if old_state_groups == new_state_groups:
-            return None, None
-
-        if len(new_state_groups) == 1 and len(old_state_groups) == 1:
-            # If we're going from one state group to another, lets check if
-            # we have a delta for that transition. If we do then we can just
-            # return that.
-
-            new_state_group = next(iter(new_state_groups))
-            old_state_group = next(iter(old_state_groups))
-
-            delta_ids = state_group_deltas.get((old_state_group, new_state_group), None)
-            if delta_ids is not None:
-                # We have a delta from the existing to new current state,
-                # so lets just return that. If we happen to already have
-                # the current state in memory then lets also return that,
-                # but it doesn't matter if we don't.
-                new_state = state_groups_map.get(new_state_group)
-                return new_state, delta_ids
-
-        # Now that we have calculated new_state_groups we need to get
-        # their state IDs so we can resolve to a single state set.
-        missing_state = new_state_groups - set(state_groups_map)
-        if missing_state:
-            group_to_state = yield self._get_state_for_groups(missing_state)
-            state_groups_map.update(group_to_state)
-
-        if len(new_state_groups) == 1:
-            # If there is only one state group, then we know what the current
-            # state is.
-            return state_groups_map[new_state_groups.pop()], None
-
-        # Ok, we need to defer to the state handler to resolve our state sets.
-
-        state_groups = {sg: state_groups_map[sg] for sg in new_state_groups}
-
-        events_map = {ev.event_id: ev for ev, _ in events_context}
-
-        # We need to get the room version, which is in the create event.
-        # Normally that'd be in the database, but its also possible that we're
-        # currently trying to persist it.
-        room_version = None
-        for ev, _ in events_context:
-            if ev.type == EventTypes.Create and ev.state_key == "":
-                room_version = ev.content.get("room_version", "1")
-                break
-
-        if not room_version:
-            room_version = yield self.get_room_version(room_id)
-
-        logger.debug("calling resolve_state_groups from preserve_events")
-        res = yield self._state_resolution_handler.resolve_state_groups(
-            room_id,
-            room_version,
-            state_groups,
-            events_map,
-            state_res_store=StateResolutionStore(self),
-        )
-
-        return res.state, None
-
-    @defer.inlineCallbacks
-    def _calculate_state_delta(self, room_id, current_state):
-        """Calculate the new state deltas for a room.
-
-        Assumes that we are only persisting events for one room at a time.
-
-        Returns:
-            tuple[list, dict] (to_delete, to_insert): where to_delete are the
-            type/state_keys to remove from current_state_events and `to_insert`
-            are the updates to current_state_events.
-        """
-        existing_state = yield self.get_current_state_ids(room_id)
-
-        to_delete = [key for key in existing_state if key not in current_state]
-
-        to_insert = {
-            key: ev_id
-            for key, ev_id in iteritems(current_state)
-            if ev_id != existing_state.get(key)
-        }
-
-        return to_delete, to_insert
-
     @log_function
     def _persist_events_txn(
         self,
@@ -1490,6 +932,13 @@ class EventsStore(
 
             self._handle_event_relations(txn, event)
 
+            # Store the labels for this event.
+            labels = event.content.get(EventContentFields.LABELS)
+            if labels:
+                self.insert_labels_for_event_txn(
+                    txn, event.event_id, labels, event.room_id, event.depth
+                )
+
         # Insert into the room_memberships table.
         self._store_room_members_txn(
             txn,
@@ -1683,7 +1132,7 @@ class EventsStore(
                 AND stream_ordering > ?
             """
             txn.execute(sql, (self.stream_ordering_day_ago,))
-            count, = txn.fetchone()
+            (count,) = txn.fetchone()
             return count
 
         ret = yield self.runInteraction("count_messages", _count_messages)
@@ -1704,7 +1153,7 @@ class EventsStore(
             """
 
             txn.execute(sql, (like_clause, self.stream_ordering_day_ago))
-            count, = txn.fetchone()
+            (count,) = txn.fetchone()
             return count
 
         ret = yield self.runInteraction("count_daily_sent_messages", _count_messages)
@@ -1719,7 +1168,7 @@ class EventsStore(
                 AND stream_ordering > ?
             """
             txn.execute(sql, (self.stream_ordering_day_ago,))
-            count, = txn.fetchone()
+            (count,) = txn.fetchone()
             return count
 
         ret = yield self.runInteraction("count_daily_active_rooms", _count)
@@ -2204,7 +1653,7 @@ class EventsStore(
         """,
             (room_id,),
         )
-        min_depth, = txn.fetchone()
+        (min_depth,) = txn.fetchone()
 
         logger.info("[purge] updating room_depth to %d", min_depth)
 
@@ -2396,7 +1845,6 @@ class EventsStore(
             "room_stats_earliest_token",
             "rooms",
             "stream_ordering_to_exterm",
-            "topics",
             "users_in_public_rooms",
             "users_who_share_private_rooms",
             # no useful index, but let's clear them anyway
@@ -2439,12 +1887,11 @@ class EventsStore(
 
         logger.info("[purge] done")
 
-    @defer.inlineCallbacks
-    def is_event_after(self, event_id1, event_id2):
+    async def is_event_after(self, event_id1, event_id2):
         """Returns True if event_id1 is after event_id2 in the stream
         """
-        to_1, so_1 = yield self._get_event_ordering(event_id1)
-        to_2, so_2 = yield self._get_event_ordering(event_id2)
+        to_1, so_1 = await self._get_event_ordering(event_id1)
+        to_2, so_2 = await self._get_event_ordering(event_id2)
         return (to_1, so_1) > (to_2, so_2)
 
     @cachedInlineCallbacks(max_entries=5000)
@@ -2477,6 +1924,33 @@ class EventsStore(
             get_all_updated_current_state_deltas_txn,
         )
 
+    def insert_labels_for_event_txn(
+        self, txn, event_id, labels, room_id, topological_ordering
+    ):
+        """Store the mapping between an event's ID and its labels, with one row per
+        (event_id, label) tuple.
+
+        Args:
+            txn (LoggingTransaction): The transaction to execute.
+            event_id (str): The event's ID.
+            labels (list[str]): A list of text labels.
+            room_id (str): The ID of the room the event was sent to.
+            topological_ordering (int): The position of the event in the room's topology.
+        """
+        return self._simple_insert_many_txn(
+            txn=txn,
+            table="event_labels",
+            values=[
+                {
+                    "event_id": event_id,
+                    "label": label,
+                    "room_id": room_id,
+                    "topological_ordering": topological_ordering,
+                }
+                for label in labels
+            ],
+        )
+
 
 AllNewEventsResult = namedtuple(
     "AllNewEventsResult",
diff --git a/synapse/storage/data_stores/main/events_bg_updates.py b/synapse/storage/data_stores/main/events_bg_updates.py
index 31ea6f917f..51352b9966 100644
--- a/synapse/storage/data_stores/main/events_bg_updates.py
+++ b/synapse/storage/data_stores/main/events_bg_updates.py
@@ -438,7 +438,7 @@ class EventsBackgroundUpdatesStore(BackgroundUpdateStore):
             if not rows:
                 return 0
 
-            upper_event_id, = rows[-1]
+            (upper_event_id,) = rows[-1]
 
             # Update the redactions with the received_ts.
             #
diff --git a/synapse/storage/data_stores/main/group_server.py b/synapse/storage/data_stores/main/group_server.py
index aeae5a2b28..b3a2771f1b 100644
--- a/synapse/storage/data_stores/main/group_server.py
+++ b/synapse/storage/data_stores/main/group_server.py
@@ -249,7 +249,7 @@ class GroupServerStore(SQLBaseStore):
                 WHERE group_id = ? AND category_id = ?
             """
             txn.execute(sql, (group_id, category_id))
-            order, = txn.fetchone()
+            (order,) = txn.fetchone()
 
         if existing:
             to_update = {}
@@ -509,7 +509,7 @@ class GroupServerStore(SQLBaseStore):
                 WHERE group_id = ? AND role_id = ?
             """
             txn.execute(sql, (group_id, role_id))
-            order, = txn.fetchone()
+            (order,) = txn.fetchone()
 
         if existing:
             to_update = {}
diff --git a/synapse/storage/data_stores/main/monthly_active_users.py b/synapse/storage/data_stores/main/monthly_active_users.py
index e6ee1e4aaa..b41c3d317a 100644
--- a/synapse/storage/data_stores/main/monthly_active_users.py
+++ b/synapse/storage/data_stores/main/monthly_active_users.py
@@ -171,7 +171,7 @@ class MonthlyActiveUsersStore(SQLBaseStore):
             sql = "SELECT COALESCE(count(*), 0) FROM monthly_active_users"
 
             txn.execute(sql)
-            count, = txn.fetchone()
+            (count,) = txn.fetchone()
             return count
 
         return self.runInteraction("count_users", _count_users)
diff --git a/synapse/storage/data_stores/main/push_rule.py b/synapse/storage/data_stores/main/push_rule.py
index cd95f1ce60..b520062d84 100644
--- a/synapse/storage/data_stores/main/push_rule.py
+++ b/synapse/storage/data_stores/main/push_rule.py
@@ -143,7 +143,7 @@ class PushRulesWorkerStore(
                     " WHERE user_id = ? AND ? < stream_id"
                 )
                 txn.execute(sql, (user_id, last_id))
-                count, = txn.fetchone()
+                (count,) = txn.fetchone()
                 return bool(count)
 
             return self.runInteraction(
diff --git a/synapse/storage/data_stores/main/pusher.py b/synapse/storage/data_stores/main/pusher.py
index f005c1ae0a..d76861cdc0 100644
--- a/synapse/storage/data_stores/main/pusher.py
+++ b/synapse/storage/data_stores/main/pusher.py
@@ -44,7 +44,7 @@ class PusherWorkerStore(SQLBaseStore):
 
                 r["data"] = json.loads(dataJson)
             except Exception as e:
-                logger.warn(
+                logger.warning(
                     "Invalid JSON in data for pusher %d: %s, %s",
                     r["id"],
                     dataJson,
diff --git a/synapse/storage/data_stores/main/registration.py b/synapse/storage/data_stores/main/registration.py
index 6c5b29288a..f70d41ecab 100644
--- a/synapse/storage/data_stores/main/registration.py
+++ b/synapse/storage/data_stores/main/registration.py
@@ -459,7 +459,7 @@ class RegistrationWorkerStore(SQLBaseStore):
                 WHERE appservice_id IS NULL
             """
             )
-            count, = txn.fetchone()
+            (count,) = txn.fetchone()
             return count
 
         ret = yield self.runInteraction("count_users", _count_users)
diff --git a/synapse/storage/data_stores/main/roommember.py b/synapse/storage/data_stores/main/roommember.py
index e47ab604dd..2af24a20b7 100644
--- a/synapse/storage/data_stores/main/roommember.py
+++ b/synapse/storage/data_stores/main/roommember.py
@@ -720,7 +720,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         # See bulk_get_push_rules_for_room for how we work around this.
         assert state_group is not None
 
-        cache = self._get_joined_hosts_cache(room_id)
+        cache = yield self._get_joined_hosts_cache(room_id)
         joined_hosts = yield cache.get_destinations(state_entry)
 
         return joined_hosts
@@ -927,7 +927,7 @@ class RoomMemberBackgroundUpdateStore(BackgroundUpdateStore):
                 if not row or not row[0]:
                     return processed, True
 
-                next_room, = row
+                (next_room,) = row
 
                 sql = """
                     UPDATE current_state_events
diff --git a/synapse/storage/data_stores/main/schema/delta/56/delete_keys_from_deleted_backups.sql b/synapse/storage/data_stores/main/schema/delta/56/delete_keys_from_deleted_backups.sql
new file mode 100644
index 0000000000..1d2ddb1b1a
--- /dev/null
+++ b/synapse/storage/data_stores/main/schema/delta/56/delete_keys_from_deleted_backups.sql
@@ -0,0 +1,25 @@
+/* Copyright 2019 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.
+ */
+
+/* delete room keys that belong to deleted room key version, or to room key
+ * versions that don't exist (anymore)
+ */
+DELETE FROM e2e_room_keys
+WHERE version NOT IN (
+  SELECT version
+  FROM e2e_room_keys_versions
+  WHERE e2e_room_keys.user_id = e2e_room_keys_versions.user_id
+  AND e2e_room_keys_versions.deleted = 0
+);
diff --git a/synapse/storage/data_stores/main/schema/delta/56/event_labels.sql b/synapse/storage/data_stores/main/schema/delta/56/event_labels.sql
new file mode 100644
index 0000000000..5e29c1da19
--- /dev/null
+++ b/synapse/storage/data_stores/main/schema/delta/56/event_labels.sql
@@ -0,0 +1,30 @@
+/* Copyright 2019 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.
+ */
+
+-- room_id and topoligical_ordering are denormalised from the events table in order to
+-- make the index work.
+CREATE TABLE IF NOT EXISTS event_labels (
+    event_id TEXT,
+    label TEXT,
+    room_id TEXT NOT NULL,
+    topological_ordering BIGINT NOT NULL,
+    PRIMARY KEY(event_id, label)
+);
+
+
+-- This index enables an event pagination looking for a particular label to index the
+-- event_labels table first, which is much quicker than scanning the events table and then
+-- filtering by label, if the label is rarely used relative to the size of the room.
+CREATE INDEX event_labels_room_id_label_idx ON event_labels(room_id, label, topological_ordering);
diff --git a/synapse/storage/data_stores/main/schema/delta/56/hidden_devices_fix.sql.sqlite b/synapse/storage/data_stores/main/schema/delta/56/hidden_devices_fix.sql.sqlite
new file mode 100644
index 0000000000..e8b1fd35d8
--- /dev/null
+++ b/synapse/storage/data_stores/main/schema/delta/56/hidden_devices_fix.sql.sqlite
@@ -0,0 +1,42 @@
+/* Copyright 2019 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.
+ */
+
+/* Change the hidden column from a default value of FALSE to a default value of
+ * 0, because sqlite3 prior to 3.23.0 caused the hidden column to contain the
+ * string 'FALSE', which is truthy.
+ *
+ * Since sqlite doesn't allow us to just change the default value, we have to
+ * recreate the table, copy the data, fix the rows that have incorrect data, and
+ * replace the old table with the new table.
+ */
+
+CREATE TABLE IF NOT EXISTS devices2 (
+    user_id TEXT NOT NULL,
+    device_id TEXT NOT NULL,
+    display_name TEXT,
+    last_seen BIGINT,
+    ip TEXT,
+    user_agent TEXT,
+    hidden BOOLEAN DEFAULT 0,
+    CONSTRAINT device_uniqueness UNIQUE (user_id, device_id)
+);
+
+INSERT INTO devices2 SELECT * FROM devices;
+
+UPDATE devices2 SET hidden = 0 WHERE hidden = 'FALSE';
+
+DROP TABLE devices;
+
+ALTER TABLE devices2 RENAME TO devices;
diff --git a/synapse/storage/data_stores/main/search.py b/synapse/storage/data_stores/main/search.py
index 0e08497452..d1d7c6863d 100644
--- a/synapse/storage/data_stores/main/search.py
+++ b/synapse/storage/data_stores/main/search.py
@@ -196,7 +196,7 @@ class SearchBackgroundUpdateStore(BackgroundUpdateStore):
                         " ON event_search USING GIN (vector)"
                     )
                 except psycopg2.ProgrammingError as e:
-                    logger.warn(
+                    logger.warning(
                         "Ignoring error %r when trying to switch from GIST to GIN", e
                     )
 
@@ -672,7 +672,7 @@ class SearchStore(SearchBackgroundUpdateStore):
                     )
                 )
                 txn.execute(query, (value, search_query))
-                headline, = txn.fetchall()[0]
+                (headline,) = txn.fetchall()[0]
 
                 # Now we need to pick the possible highlights out of the haedline
                 # result.
diff --git a/synapse/storage/data_stores/main/state.py b/synapse/storage/data_stores/main/state.py
index d54442e5fa..3132848034 100644
--- a/synapse/storage/data_stores/main/state.py
+++ b/synapse/storage/data_stores/main/state.py
@@ -15,6 +15,7 @@
 
 import logging
 from collections import namedtuple
+from typing import Iterable, Tuple
 
 from six import iteritems, itervalues
 from six.moves import range
@@ -23,6 +24,8 @@ from twisted.internet import defer
 
 from synapse.api.constants import EventTypes
 from synapse.api.errors import NotFoundError
+from synapse.events import EventBase
+from synapse.events.snapshot import EventContext
 from synapse.storage._base import SQLBaseStore
 from synapse.storage.background_updates import BackgroundUpdateStore
 from synapse.storage.data_stores.main.events_worker import EventsWorkerStore
@@ -722,16 +725,18 @@ class StateGroupWorkerStore(
         member_filter, non_member_filter = state_filter.get_member_split()
 
         # Now we look them up in the member and non-member caches
-        non_member_state, incomplete_groups_nm, = (
-            yield self._get_state_for_groups_using_cache(
-                groups, self._state_group_cache, state_filter=non_member_filter
-            )
+        (
+            non_member_state,
+            incomplete_groups_nm,
+        ) = yield self._get_state_for_groups_using_cache(
+            groups, self._state_group_cache, state_filter=non_member_filter
         )
 
-        member_state, incomplete_groups_m, = (
-            yield self._get_state_for_groups_using_cache(
-                groups, self._state_group_members_cache, state_filter=member_filter
-            )
+        (
+            member_state,
+            incomplete_groups_m,
+        ) = yield self._get_state_for_groups_using_cache(
+            groups, self._state_group_members_cache, state_filter=member_filter
         )
 
         state = dict(non_member_state)
@@ -1073,7 +1078,7 @@ class StateBackgroundUpdateStore(
                     " WHERE id < ? AND room_id = ?",
                     (state_group, room_id),
                 )
-                prev_group, = txn.fetchone()
+                (prev_group,) = txn.fetchone()
                 new_last_state_group = state_group
 
                 if prev_group:
@@ -1215,7 +1220,9 @@ class StateStore(StateGroupWorkerStore, StateBackgroundUpdateStore):
     def __init__(self, db_conn, hs):
         super(StateStore, self).__init__(db_conn, hs)
 
-    def _store_event_state_mappings_txn(self, txn, events_and_contexts):
+    def _store_event_state_mappings_txn(
+        self, txn, events_and_contexts: Iterable[Tuple[EventBase, EventContext]]
+    ):
         state_groups = {}
         for event, context in events_and_contexts:
             if event.internal_metadata.is_outlier():
diff --git a/synapse/storage/data_stores/main/stats.py b/synapse/storage/data_stores/main/stats.py
index 5ab639b2ad..45b3de7d56 100644
--- a/synapse/storage/data_stores/main/stats.py
+++ b/synapse/storage/data_stores/main/stats.py
@@ -332,7 +332,7 @@ class StatsStore(StateDeltasStore):
         def _bulk_update_stats_delta_txn(txn):
             for stats_type, stats_updates in updates.items():
                 for stats_id, fields in stats_updates.items():
-                    logger.info(
+                    logger.debug(
                         "Updating %s stats for %s: %s", stats_type, stats_id, fields
                     )
                     self._update_stats_delta_txn(
@@ -773,7 +773,7 @@ class StatsStore(StateDeltasStore):
                 (room_id,),
             )
 
-            current_state_events_count, = txn.fetchone()
+            (current_state_events_count,) = txn.fetchone()
 
             users_in_room = self.get_users_in_room_txn(txn, room_id)
 
@@ -863,7 +863,7 @@ class StatsStore(StateDeltasStore):
                 """,
                 (user_id,),
             )
-            count, = txn.fetchone()
+            (count,) = txn.fetchone()
             return count, pos
 
         joined_rooms, pos = yield self.runInteraction(
diff --git a/synapse/storage/data_stores/main/stream.py b/synapse/storage/data_stores/main/stream.py
index 263999dfca..616ef91d4e 100644
--- a/synapse/storage/data_stores/main/stream.py
+++ b/synapse/storage/data_stores/main/stream.py
@@ -229,6 +229,14 @@ def filter_to_clause(event_filter):
         clauses.append("contains_url = ?")
         args.append(event_filter.contains_url)
 
+    # We're only applying the "labels" filter on the database query, because applying the
+    # "not_labels" filter via a SQL query is non-trivial. Instead, we let
+    # event_filter.check_fields apply it, which is not as efficient but makes the
+    # implementation simpler.
+    if event_filter.labels:
+        clauses.append("(%s)" % " OR ".join("label = ?" for _ in event_filter.labels))
+        args.extend(event_filter.labels)
+
     return " AND ".join(clauses), args
 
 
@@ -864,8 +872,9 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore):
         args.append(int(limit))
 
         sql = (
-            "SELECT event_id, topological_ordering, stream_ordering"
+            "SELECT DISTINCT event_id, topological_ordering, stream_ordering"
             " FROM events"
+            " LEFT JOIN event_labels USING (event_id, room_id, topological_ordering)"
             " WHERE outlier = ? AND room_id = ? AND %(bounds)s"
             " ORDER BY topological_ordering %(order)s,"
             " stream_ordering %(order)s LIMIT ?"
diff --git a/synapse/storage/persist_events.py b/synapse/storage/persist_events.py
new file mode 100644
index 0000000000..fa03ca9ff7
--- /dev/null
+++ b/synapse/storage/persist_events.py
@@ -0,0 +1,649 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014-2016 OpenMarket Ltd
+# Copyright 2018-2019 New Vector Ltd
+# Copyright 2019 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 logging
+from collections import deque, namedtuple
+
+from six import iteritems
+from six.moves import range
+
+from prometheus_client import Counter, Histogram
+
+from twisted.internet import defer
+
+from synapse.api.constants import EventTypes
+from synapse.logging.context import PreserveLoggingContext, make_deferred_yieldable
+from synapse.metrics.background_process_metrics import run_as_background_process
+from synapse.state import StateResolutionStore
+from synapse.storage.data_stores import DataStores
+from synapse.util.async_helpers import ObservableDeferred
+from synapse.util.metrics import Measure
+
+logger = logging.getLogger(__name__)
+
+# The number of times we are recalculating the current state
+state_delta_counter = Counter("synapse_storage_events_state_delta", "")
+
+# The number of times we are recalculating state when there is only a
+# single forward extremity
+state_delta_single_event_counter = Counter(
+    "synapse_storage_events_state_delta_single_event", ""
+)
+
+# The number of times we are reculating state when we could have resonably
+# calculated the delta when we calculated the state for an event we were
+# persisting.
+state_delta_reuse_delta_counter = Counter(
+    "synapse_storage_events_state_delta_reuse_delta", ""
+)
+
+# The number of forward extremities for each new event.
+forward_extremities_counter = Histogram(
+    "synapse_storage_events_forward_extremities_persisted",
+    "Number of forward extremities for each new event",
+    buckets=(1, 2, 3, 5, 7, 10, 15, 20, 50, 100, 200, 500, "+Inf"),
+)
+
+# The number of stale forward extremities for each new event. Stale extremities
+# are those that were in the previous set of extremities as well as the new.
+stale_forward_extremities_counter = Histogram(
+    "synapse_storage_events_stale_forward_extremities_persisted",
+    "Number of unchanged forward extremities for each new event",
+    buckets=(0, 1, 2, 3, 5, 7, 10, 15, 20, 50, 100, 200, 500, "+Inf"),
+)
+
+
+class _EventPeristenceQueue(object):
+    """Queues up events so that they can be persisted in bulk with only one
+    concurrent transaction per room.
+    """
+
+    _EventPersistQueueItem = namedtuple(
+        "_EventPersistQueueItem", ("events_and_contexts", "backfilled", "deferred")
+    )
+
+    def __init__(self):
+        self._event_persist_queues = {}
+        self._currently_persisting_rooms = set()
+
+    def add_to_queue(self, room_id, events_and_contexts, backfilled):
+        """Add events to the queue, with the given persist_event options.
+
+        NB: due to the normal usage pattern of this method, it does *not*
+        follow the synapse logcontext rules, and leaves the logcontext in
+        place whether or not the returned deferred is ready.
+
+        Args:
+            room_id (str):
+            events_and_contexts (list[(EventBase, EventContext)]):
+            backfilled (bool):
+
+        Returns:
+            defer.Deferred: a deferred which will resolve once the events are
+                persisted. Runs its callbacks *without* a logcontext.
+        """
+        queue = self._event_persist_queues.setdefault(room_id, deque())
+        if queue:
+            # if the last item in the queue has the same `backfilled` setting,
+            # we can just add these new events to that item.
+            end_item = queue[-1]
+            if end_item.backfilled == backfilled:
+                end_item.events_and_contexts.extend(events_and_contexts)
+                return end_item.deferred.observe()
+
+        deferred = ObservableDeferred(defer.Deferred(), consumeErrors=True)
+
+        queue.append(
+            self._EventPersistQueueItem(
+                events_and_contexts=events_and_contexts,
+                backfilled=backfilled,
+                deferred=deferred,
+            )
+        )
+
+        return deferred.observe()
+
+    def handle_queue(self, room_id, per_item_callback):
+        """Attempts to handle the queue for a room if not already being handled.
+
+        The given callback will be invoked with for each item in the queue,
+        of type _EventPersistQueueItem. The per_item_callback will continuously
+        be called with new items, unless the queue becomnes empty. The return
+        value of the function will be given to the deferreds waiting on the item,
+        exceptions will be passed to the deferreds as well.
+
+        This function should therefore be called whenever anything is added
+        to the queue.
+
+        If another callback is currently handling the queue then it will not be
+        invoked.
+        """
+
+        if room_id in self._currently_persisting_rooms:
+            return
+
+        self._currently_persisting_rooms.add(room_id)
+
+        @defer.inlineCallbacks
+        def handle_queue_loop():
+            try:
+                queue = self._get_drainining_queue(room_id)
+                for item in queue:
+                    try:
+                        ret = yield per_item_callback(item)
+                    except Exception:
+                        with PreserveLoggingContext():
+                            item.deferred.errback()
+                    else:
+                        with PreserveLoggingContext():
+                            item.deferred.callback(ret)
+            finally:
+                queue = self._event_persist_queues.pop(room_id, None)
+                if queue:
+                    self._event_persist_queues[room_id] = queue
+                self._currently_persisting_rooms.discard(room_id)
+
+        # set handle_queue_loop off in the background
+        run_as_background_process("persist_events", handle_queue_loop)
+
+    def _get_drainining_queue(self, room_id):
+        queue = self._event_persist_queues.setdefault(room_id, deque())
+
+        try:
+            while True:
+                yield queue.popleft()
+        except IndexError:
+            # Queue has been drained.
+            pass
+
+
+class EventsPersistenceStorage(object):
+    """High level interface for handling persisting newly received events.
+
+    Takes care of batching up events by room, and calculating the necessary
+    current state and forward extremity changes.
+    """
+
+    def __init__(self, hs, stores: DataStores):
+        # We ultimately want to split out the state store from the main store,
+        # so we use separate variables here even though they point to the same
+        # store for now.
+        self.main_store = stores.main
+        self.state_store = stores.main
+
+        self._clock = hs.get_clock()
+        self.is_mine_id = hs.is_mine_id
+        self._event_persist_queue = _EventPeristenceQueue()
+        self._state_resolution_handler = hs.get_state_resolution_handler()
+
+    @defer.inlineCallbacks
+    def persist_events(self, events_and_contexts, backfilled=False):
+        """
+        Write events to the database
+        Args:
+            events_and_contexts: list of tuples of (event, context)
+            backfilled (bool): Whether the results are retrieved from federation
+                via backfill or not. Used to determine if they're "new" events
+                which might update the current state etc.
+
+        Returns:
+            Deferred[int]: the stream ordering of the latest persisted event
+        """
+        partitioned = {}
+        for event, ctx in events_and_contexts:
+            partitioned.setdefault(event.room_id, []).append((event, ctx))
+
+        deferreds = []
+        for room_id, evs_ctxs in iteritems(partitioned):
+            d = self._event_persist_queue.add_to_queue(
+                room_id, evs_ctxs, backfilled=backfilled
+            )
+            deferreds.append(d)
+
+        for room_id in partitioned:
+            self._maybe_start_persisting(room_id)
+
+        yield make_deferred_yieldable(
+            defer.gatherResults(deferreds, consumeErrors=True)
+        )
+
+        max_persisted_id = yield self.main_store.get_current_events_token()
+
+        return max_persisted_id
+
+    @defer.inlineCallbacks
+    def persist_event(self, event, context, backfilled=False):
+        """
+
+        Args:
+            event (EventBase):
+            context (EventContext):
+            backfilled (bool):
+
+        Returns:
+            Deferred: resolves to (int, int): the stream ordering of ``event``,
+            and the stream ordering of the latest persisted event
+        """
+        deferred = self._event_persist_queue.add_to_queue(
+            event.room_id, [(event, context)], backfilled=backfilled
+        )
+
+        self._maybe_start_persisting(event.room_id)
+
+        yield make_deferred_yieldable(deferred)
+
+        max_persisted_id = yield self.main_store.get_current_events_token()
+        return (event.internal_metadata.stream_ordering, max_persisted_id)
+
+    def _maybe_start_persisting(self, room_id):
+        @defer.inlineCallbacks
+        def persisting_queue(item):
+            with Measure(self._clock, "persist_events"):
+                yield self._persist_events(
+                    item.events_and_contexts, backfilled=item.backfilled
+                )
+
+        self._event_persist_queue.handle_queue(room_id, persisting_queue)
+
+    @defer.inlineCallbacks
+    def _persist_events(self, events_and_contexts, backfilled=False):
+        """Calculates the change to current state and forward extremities, and
+        persists the given events and with those updates.
+
+        Args:
+            events_and_contexts (list[(EventBase, EventContext)]):
+            backfilled (bool):
+            delete_existing (bool):
+
+        Returns:
+            Deferred: resolves when the events have been persisted
+        """
+        if not events_and_contexts:
+            return
+
+        chunks = [
+            events_and_contexts[x : x + 100]
+            for x in range(0, len(events_and_contexts), 100)
+        ]
+
+        for chunk in chunks:
+            # We can't easily parallelize these since different chunks
+            # might contain the same event. :(
+
+            # NB: Assumes that we are only persisting events for one room
+            # at a time.
+
+            # map room_id->list[event_ids] giving the new forward
+            # extremities in each room
+            new_forward_extremeties = {}
+
+            # map room_id->(type,state_key)->event_id tracking the full
+            # state in each room after adding these events.
+            # This is simply used to prefill the get_current_state_ids
+            # cache
+            current_state_for_room = {}
+
+            # map room_id->(to_delete, to_insert) where to_delete is a list
+            # of type/state keys to remove from current state, and to_insert
+            # is a map (type,key)->event_id giving the state delta in each
+            # room
+            state_delta_for_room = {}
+
+            if not backfilled:
+                with Measure(self._clock, "_calculate_state_and_extrem"):
+                    # Work out the new "current state" for each room.
+                    # We do this by working out what the new extremities are and then
+                    # calculating the state from that.
+                    events_by_room = {}
+                    for event, context in chunk:
+                        events_by_room.setdefault(event.room_id, []).append(
+                            (event, context)
+                        )
+
+                    for room_id, ev_ctx_rm in iteritems(events_by_room):
+                        latest_event_ids = yield self.main_store.get_latest_event_ids_in_room(
+                            room_id
+                        )
+                        new_latest_event_ids = yield self._calculate_new_extremities(
+                            room_id, ev_ctx_rm, latest_event_ids
+                        )
+
+                        latest_event_ids = set(latest_event_ids)
+                        if new_latest_event_ids == latest_event_ids:
+                            # No change in extremities, so no change in state
+                            continue
+
+                        # there should always be at least one forward extremity.
+                        # (except during the initial persistence of the send_join
+                        # results, in which case there will be no existing
+                        # extremities, so we'll `continue` above and skip this bit.)
+                        assert new_latest_event_ids, "No forward extremities left!"
+
+                        new_forward_extremeties[room_id] = new_latest_event_ids
+
+                        len_1 = (
+                            len(latest_event_ids) == 1
+                            and len(new_latest_event_ids) == 1
+                        )
+                        if len_1:
+                            all_single_prev_not_state = all(
+                                len(event.prev_event_ids()) == 1
+                                and not event.is_state()
+                                for event, ctx in ev_ctx_rm
+                            )
+                            # Don't bother calculating state if they're just
+                            # a long chain of single ancestor non-state events.
+                            if all_single_prev_not_state:
+                                continue
+
+                        state_delta_counter.inc()
+                        if len(new_latest_event_ids) == 1:
+                            state_delta_single_event_counter.inc()
+
+                            # This is a fairly handwavey check to see if we could
+                            # have guessed what the delta would have been when
+                            # processing one of these events.
+                            # What we're interested in is if the latest extremities
+                            # were the same when we created the event as they are
+                            # now. When this server creates a new event (as opposed
+                            # to receiving it over federation) it will use the
+                            # forward extremities as the prev_events, so we can
+                            # guess this by looking at the prev_events and checking
+                            # if they match the current forward extremities.
+                            for ev, _ in ev_ctx_rm:
+                                prev_event_ids = set(ev.prev_event_ids())
+                                if latest_event_ids == prev_event_ids:
+                                    state_delta_reuse_delta_counter.inc()
+                                    break
+
+                        logger.info("Calculating state delta for room %s", room_id)
+                        with Measure(
+                            self._clock, "persist_events.get_new_state_after_events"
+                        ):
+                            res = yield self._get_new_state_after_events(
+                                room_id,
+                                ev_ctx_rm,
+                                latest_event_ids,
+                                new_latest_event_ids,
+                            )
+                            current_state, delta_ids = res
+
+                        # If either are not None then there has been a change,
+                        # and we need to work out the delta (or use that
+                        # given)
+                        if delta_ids is not None:
+                            # If there is a delta we know that we've
+                            # only added or replaced state, never
+                            # removed keys entirely.
+                            state_delta_for_room[room_id] = ([], delta_ids)
+                        elif current_state is not None:
+                            with Measure(
+                                self._clock, "persist_events.calculate_state_delta"
+                            ):
+                                delta = yield self._calculate_state_delta(
+                                    room_id, current_state
+                                )
+                            state_delta_for_room[room_id] = delta
+
+                        # If we have the current_state then lets prefill
+                        # the cache with it.
+                        if current_state is not None:
+                            current_state_for_room[room_id] = current_state
+
+            yield self.main_store._persist_events_and_state_updates(
+                chunk,
+                current_state_for_room=current_state_for_room,
+                state_delta_for_room=state_delta_for_room,
+                new_forward_extremeties=new_forward_extremeties,
+                backfilled=backfilled,
+            )
+
+    @defer.inlineCallbacks
+    def _calculate_new_extremities(self, room_id, event_contexts, latest_event_ids):
+        """Calculates the new forward extremities for a room given events to
+        persist.
+
+        Assumes that we are only persisting events for one room at a time.
+        """
+
+        # we're only interested in new events which aren't outliers and which aren't
+        # being rejected.
+        new_events = [
+            event
+            for event, ctx in event_contexts
+            if not event.internal_metadata.is_outlier()
+            and not ctx.rejected
+            and not event.internal_metadata.is_soft_failed()
+        ]
+
+        latest_event_ids = set(latest_event_ids)
+
+        # start with the existing forward extremities
+        result = set(latest_event_ids)
+
+        # add all the new events to the list
+        result.update(event.event_id for event in new_events)
+
+        # Now remove all events which are prev_events of any of the new events
+        result.difference_update(
+            e_id for event in new_events for e_id in event.prev_event_ids()
+        )
+
+        # Remove any events which are prev_events of any existing events.
+        existing_prevs = yield self.main_store._get_events_which_are_prevs(result)
+        result.difference_update(existing_prevs)
+
+        # Finally handle the case where the new events have soft-failed prev
+        # events. If they do we need to remove them and their prev events,
+        # otherwise we end up with dangling extremities.
+        existing_prevs = yield self.main_store._get_prevs_before_rejected(
+            e_id for event in new_events for e_id in event.prev_event_ids()
+        )
+        result.difference_update(existing_prevs)
+
+        # We only update metrics for events that change forward extremities
+        # (e.g. we ignore backfill/outliers/etc)
+        if result != latest_event_ids:
+            forward_extremities_counter.observe(len(result))
+            stale = latest_event_ids & result
+            stale_forward_extremities_counter.observe(len(stale))
+
+        return result
+
+    @defer.inlineCallbacks
+    def _get_new_state_after_events(
+        self, room_id, events_context, old_latest_event_ids, new_latest_event_ids
+    ):
+        """Calculate the current state dict after adding some new events to
+        a room
+
+        Args:
+            room_id (str):
+                room to which the events are being added. Used for logging etc
+
+            events_context (list[(EventBase, EventContext)]):
+                events and contexts which are being added to the room
+
+            old_latest_event_ids (iterable[str]):
+                the old forward extremities for the room.
+
+            new_latest_event_ids (iterable[str]):
+                the new forward extremities for the room.
+
+        Returns:
+            Deferred[tuple[dict[(str,str), str]|None, dict[(str,str), str]|None]]:
+            Returns a tuple of two state maps, the first being the full new current
+            state and the second being the delta to the existing current state.
+            If both are None then there has been no change.
+
+            If there has been a change then we only return the delta if its
+            already been calculated. Conversely if we do know the delta then
+            the new current state is only returned if we've already calculated
+            it.
+        """
+        # map from state_group to ((type, key) -> event_id) state map
+        state_groups_map = {}
+
+        # Map from (prev state group, new state group) -> delta state dict
+        state_group_deltas = {}
+
+        for ev, ctx in events_context:
+            if ctx.state_group is None:
+                # This should only happen for outlier events.
+                if not ev.internal_metadata.is_outlier():
+                    raise Exception(
+                        "Context for new event %s has no state "
+                        "group" % (ev.event_id,)
+                    )
+                continue
+
+            if ctx.state_group in state_groups_map:
+                continue
+
+            # We're only interested in pulling out state that has already
+            # been cached in the context. We'll pull stuff out of the DB later
+            # if necessary.
+            current_state_ids = ctx.get_cached_current_state_ids()
+            if current_state_ids is not None:
+                state_groups_map[ctx.state_group] = current_state_ids
+
+            if ctx.prev_group:
+                state_group_deltas[(ctx.prev_group, ctx.state_group)] = ctx.delta_ids
+
+        # We need to map the event_ids to their state groups. First, let's
+        # check if the event is one we're persisting, in which case we can
+        # pull the state group from its context.
+        # Otherwise we need to pull the state group from the database.
+
+        # Set of events we need to fetch groups for. (We know none of the old
+        # extremities are going to be in events_context).
+        missing_event_ids = set(old_latest_event_ids)
+
+        event_id_to_state_group = {}
+        for event_id in new_latest_event_ids:
+            # First search in the list of new events we're adding.
+            for ev, ctx in events_context:
+                if event_id == ev.event_id and ctx.state_group is not None:
+                    event_id_to_state_group[event_id] = ctx.state_group
+                    break
+            else:
+                # If we couldn't find it, then we'll need to pull
+                # the state from the database
+                missing_event_ids.add(event_id)
+
+        if missing_event_ids:
+            # Now pull out the state groups for any missing events from DB
+            event_to_groups = yield self.main_store._get_state_group_for_events(
+                missing_event_ids
+            )
+            event_id_to_state_group.update(event_to_groups)
+
+        # State groups of old_latest_event_ids
+        old_state_groups = set(
+            event_id_to_state_group[evid] for evid in old_latest_event_ids
+        )
+
+        # State groups of new_latest_event_ids
+        new_state_groups = set(
+            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.
+        if old_state_groups == new_state_groups:
+            return None, None
+
+        if len(new_state_groups) == 1 and len(old_state_groups) == 1:
+            # If we're going from one state group to another, lets check if
+            # we have a delta for that transition. If we do then we can just
+            # return that.
+
+            new_state_group = next(iter(new_state_groups))
+            old_state_group = next(iter(old_state_groups))
+
+            delta_ids = state_group_deltas.get((old_state_group, new_state_group), None)
+            if delta_ids is not None:
+                # We have a delta from the existing to new current state,
+                # so lets just return that. If we happen to already have
+                # the current state in memory then lets also return that,
+                # but it doesn't matter if we don't.
+                new_state = state_groups_map.get(new_state_group)
+                return new_state, delta_ids
+
+        # Now that we have calculated new_state_groups we need to get
+        # their state IDs so we can resolve to a single state set.
+        missing_state = new_state_groups - set(state_groups_map)
+        if missing_state:
+            group_to_state = yield self.state_store._get_state_for_groups(missing_state)
+            state_groups_map.update(group_to_state)
+
+        if len(new_state_groups) == 1:
+            # If there is only one state group, then we know what the current
+            # state is.
+            return state_groups_map[new_state_groups.pop()], None
+
+        # Ok, we need to defer to the state handler to resolve our state sets.
+
+        state_groups = {sg: state_groups_map[sg] for sg in new_state_groups}
+
+        events_map = {ev.event_id: ev for ev, _ in events_context}
+
+        # We need to get the room version, which is in the create event.
+        # Normally that'd be in the database, but its also possible that we're
+        # currently trying to persist it.
+        room_version = None
+        for ev, _ in events_context:
+            if ev.type == EventTypes.Create and ev.state_key == "":
+                room_version = ev.content.get("room_version", "1")
+                break
+
+        if not room_version:
+            room_version = yield self.main_store.get_room_version(room_id)
+
+        logger.debug("calling resolve_state_groups from preserve_events")
+        res = yield self._state_resolution_handler.resolve_state_groups(
+            room_id,
+            room_version,
+            state_groups,
+            events_map,
+            state_res_store=StateResolutionStore(self.main_store),
+        )
+
+        return res.state, None
+
+    @defer.inlineCallbacks
+    def _calculate_state_delta(self, room_id, current_state):
+        """Calculate the new state deltas for a room.
+
+        Assumes that we are only persisting events for one room at a time.
+
+        Returns:
+            tuple[list, dict] (to_delete, to_insert): where to_delete are the
+            type/state_keys to remove from current_state_events and `to_insert`
+            are the updates to current_state_events.
+        """
+        existing_state = yield self.main_store.get_current_state_ids(room_id)
+
+        to_delete = [key for key in existing_state if key not in current_state]
+
+        to_insert = {
+            key: ev_id
+            for key, ev_id in iteritems(current_state)
+            if ev_id != existing_state.get(key)
+        }
+
+        return to_delete, to_insert
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index a2df8fa827..3735846899 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -19,6 +19,8 @@ from six import iteritems, itervalues
 
 import attr
 
+from twisted.internet import defer
+
 from synapse.api.constants import EventTypes
 
 logger = logging.getLogger(__name__)
@@ -322,3 +324,234 @@ class StateFilter(object):
         )
 
         return member_filter, non_member_filter
+
+
+class StateGroupStorage(object):
+    """High level interface to fetching state for event.
+    """
+
+    def __init__(self, hs, stores):
+        self.stores = stores
+
+    def get_state_group_delta(self, state_group):
+        """Given a state group try to return a previous group and a delta between
+        the old and the new.
+
+        Returns:
+            Deferred[Tuple[Optional[int], Optional[list[dict[tuple[str, str], str]]]]]):
+                (prev_group, delta_ids)
+        """
+
+        return self.stores.main.get_state_group_delta(state_group)
+
+    @defer.inlineCallbacks
+    def get_state_groups_ids(self, _room_id, event_ids):
+        """Get the event IDs of all the state for the state groups for the given events
+
+        Args:
+            _room_id (str): id of the room for these events
+            event_ids (iterable[str]): ids of the events
+
+        Returns:
+            Deferred[dict[int, dict[tuple[str, str], str]]]:
+                dict of state_group_id -> (dict of (type, state_key) -> event id)
+        """
+        if not event_ids:
+            return {}
+
+        event_to_groups = yield self.stores.main._get_state_group_for_events(event_ids)
+
+        groups = set(itervalues(event_to_groups))
+        group_to_state = yield self.stores.main._get_state_for_groups(groups)
+
+        return group_to_state
+
+    @defer.inlineCallbacks
+    def get_state_ids_for_group(self, state_group):
+        """Get the event IDs of all the state in the given state group
+
+        Args:
+            state_group (int)
+
+        Returns:
+            Deferred[dict]: Resolves to a map of (type, state_key) -> event_id
+        """
+        group_to_state = yield self._get_state_for_groups((state_group,))
+
+        return group_to_state[state_group]
+
+    @defer.inlineCallbacks
+    def get_state_groups(self, room_id, event_ids):
+        """ Get the state groups for the given list of event_ids
+        Returns:
+            Deferred[dict[int, list[EventBase]]]:
+                dict of state_group_id -> list of state events.
+        """
+        if not event_ids:
+            return {}
+
+        group_to_ids = yield self.get_state_groups_ids(room_id, event_ids)
+
+        state_event_map = yield self.stores.main.get_events(
+            [
+                ev_id
+                for group_ids in itervalues(group_to_ids)
+                for ev_id in itervalues(group_ids)
+            ],
+            get_prev_content=False,
+        )
+
+        return {
+            group: [
+                state_event_map[v]
+                for v in itervalues(event_id_map)
+                if v in state_event_map
+            ]
+            for group, event_id_map in iteritems(group_to_ids)
+        }
+
+    def _get_state_groups_from_groups(self, groups, state_filter):
+        """Returns the state groups for a given set of groups, filtering on
+        types of state events.
+
+        Args:
+            groups(list[int]): list of state group IDs to query
+            state_filter (StateFilter): The state filter used to fetch state
+                from the database.
+        Returns:
+            Deferred[dict[int, dict[tuple[str, str], str]]]:
+                dict of state_group_id -> (dict of (type, state_key) -> event id)
+        """
+
+        return self.stores.main._get_state_groups_from_groups(groups, state_filter)
+
+    @defer.inlineCallbacks
+    def get_state_for_events(self, event_ids, state_filter=StateFilter.all()):
+        """Given a list of event_ids and type tuples, return a list of state
+        dicts for each event.
+        Args:
+            event_ids (list[string])
+            state_filter (StateFilter): The state filter used to fetch state
+                from the database.
+        Returns:
+            deferred: A dict of (event_id) -> (type, state_key) -> [state_events]
+        """
+        event_to_groups = yield self.stores.main._get_state_group_for_events(event_ids)
+
+        groups = set(itervalues(event_to_groups))
+        group_to_state = yield self.stores.main._get_state_for_groups(
+            groups, state_filter
+        )
+
+        state_event_map = yield self.stores.main.get_events(
+            [ev_id for sd in itervalues(group_to_state) for ev_id in itervalues(sd)],
+            get_prev_content=False,
+        )
+
+        event_to_state = {
+            event_id: {
+                k: state_event_map[v]
+                for k, v in iteritems(group_to_state[group])
+                if v in state_event_map
+            }
+            for event_id, group in iteritems(event_to_groups)
+        }
+
+        return {event: event_to_state[event] for event in event_ids}
+
+    @defer.inlineCallbacks
+    def get_state_ids_for_events(self, event_ids, state_filter=StateFilter.all()):
+        """
+        Get the state dicts corresponding to a list of events, containing the event_ids
+        of the state events (as opposed to the events themselves)
+
+        Args:
+            event_ids(list(str)): events whose state should be returned
+            state_filter (StateFilter): The state filter used to fetch state
+                from the database.
+
+        Returns:
+            A deferred dict from event_id -> (type, state_key) -> event_id
+        """
+        event_to_groups = yield self.stores.main._get_state_group_for_events(event_ids)
+
+        groups = set(itervalues(event_to_groups))
+        group_to_state = yield self.stores.main._get_state_for_groups(
+            groups, state_filter
+        )
+
+        event_to_state = {
+            event_id: group_to_state[group]
+            for event_id, group in iteritems(event_to_groups)
+        }
+
+        return {event: event_to_state[event] for event in event_ids}
+
+    @defer.inlineCallbacks
+    def get_state_for_event(self, event_id, state_filter=StateFilter.all()):
+        """
+        Get the state dict corresponding to a particular event
+
+        Args:
+            event_id(str): event whose state should be returned
+            state_filter (StateFilter): The state filter used to fetch state
+                from the database.
+
+        Returns:
+            A deferred dict from (type, state_key) -> state_event
+        """
+        state_map = yield self.get_state_for_events([event_id], state_filter)
+        return state_map[event_id]
+
+    @defer.inlineCallbacks
+    def get_state_ids_for_event(self, event_id, state_filter=StateFilter.all()):
+        """
+        Get the state dict corresponding to a particular event
+
+        Args:
+            event_id(str): event whose state should be returned
+            state_filter (StateFilter): The state filter used to fetch state
+                from the database.
+
+        Returns:
+            A deferred dict from (type, state_key) -> state_event
+        """
+        state_map = yield self.get_state_ids_for_events([event_id], state_filter)
+        return state_map[event_id]
+
+    def _get_state_for_groups(self, groups, state_filter=StateFilter.all()):
+        """Gets the state at each of a list of state groups, optionally
+        filtering by type/state_key
+
+        Args:
+            groups (iterable[int]): list of state groups for which we want
+                to get the state.
+            state_filter (StateFilter): The state filter used to fetch state
+                from the database.
+        Returns:
+            Deferred[dict[int, dict[tuple[str, str], str]]]:
+                dict of state_group_id -> (dict of (type, state_key) -> event id)
+        """
+        return self.stores.main._get_state_for_groups(groups, state_filter)
+
+    def store_state_group(
+        self, event_id, room_id, prev_group, delta_ids, current_state_ids
+    ):
+        """Store a new set of state, returning a newly assigned state group.
+
+        Args:
+            event_id (str): The event ID for which the state was calculated
+            room_id (str)
+            prev_group (int|None): A previous state group for the room, optional.
+            delta_ids (dict|None): The delta between state at `prev_group` and
+                `current_state_ids`, if `prev_group` was given. Same format as
+                `current_state_ids`.
+            current_state_ids (dict): The state to store. Map of (type, state_key)
+                to event_id.
+
+        Returns:
+            Deferred[int]: The state group ID
+        """
+        return self.stores.main.store_state_group(
+            event_id, room_id, prev_group, delta_ids, current_state_ids
+        )
diff --git a/synapse/storage/util/id_generators.py b/synapse/storage/util/id_generators.py
index cbb0a4810a..9d851beaa5 100644
--- a/synapse/storage/util/id_generators.py
+++ b/synapse/storage/util/id_generators.py
@@ -46,7 +46,7 @@ def _load_current_id(db_conn, table, column, step=1):
         cur.execute("SELECT MAX(%s) FROM %s" % (column, table))
     else:
         cur.execute("SELECT MIN(%s) FROM %s" % (column, table))
-    val, = cur.fetchone()
+    (val,) = cur.fetchone()
     cur.close()
     current_id = int(val) if val else step
     return (max if step > 0 else min)(current_id, step)
diff --git a/synapse/util/async_helpers.py b/synapse/util/async_helpers.py
index 804dbca443..5c4de2e69f 100644
--- a/synapse/util/async_helpers.py
+++ b/synapse/util/async_helpers.py
@@ -86,11 +86,12 @@ class ObservableDeferred(object):
 
         deferred.addCallbacks(callback, errback)
 
-    def observe(self):
+    def observe(self) -> defer.Deferred:
         """Observe the underlying deferred.
 
-        Can return either a deferred if the underlying deferred is still pending
-        (or has failed), or the actual value. Callers may need to use maybeDeferred.
+        This returns a brand new deferred that is resolved when the underlying
+        deferred is resolved. Interacting with the returned deferred does not
+        effect the underdlying deferred.
         """
         if not self._result:
             d = defer.Deferred()
@@ -105,7 +106,7 @@ class ObservableDeferred(object):
             return d
         else:
             success, res = self._result
-            return res if success else defer.fail(res)
+            return defer.succeed(res) if success else defer.fail(res)
 
     def observers(self):
         return self._observers
@@ -138,7 +139,7 @@ def concurrently_execute(func, args, limit):
     the number of concurrent executions.
 
     Args:
-        func (func): Function to execute, should return a deferred.
+        func (func): Function to execute, should return a deferred or coroutine.
         args (list): List of arguments to pass to func, each invocation of func
             gets a signle argument.
         limit (int): Maximum number of conccurent executions.
@@ -148,11 +149,10 @@ def concurrently_execute(func, args, limit):
     """
     it = iter(args)
 
-    @defer.inlineCallbacks
-    def _concurrently_execute_inner():
+    async def _concurrently_execute_inner():
         try:
             while True:
-                yield func(next(it))
+                await maybe_awaitable(func(next(it)))
         except StopIteration:
             pass
 
@@ -309,7 +309,7 @@ class Linearizer(object):
                 )
 
             else:
-                logger.warn(
+                logger.warning(
                     "Unexpected exception waiting for linearizer lock %r for key %r",
                     self.name,
                     key,
diff --git a/synapse/util/caches/__init__.py b/synapse/util/caches/__init__.py
index 43fd65d693..da5077b471 100644
--- a/synapse/util/caches/__init__.py
+++ b/synapse/util/caches/__init__.py
@@ -107,7 +107,7 @@ def register_cache(cache_type, cache_name, cache, collect_callback=None):
                 if collect_callback:
                     collect_callback()
             except Exception as e:
-                logger.warn("Error calculating metrics for %s: %s", cache_name, e)
+                logger.warning("Error calculating metrics for %s: %s", cache_name, e)
                 raise
 
             yield GaugeMetricFamily("__unused", "")
diff --git a/synapse/util/caches/descriptors.py b/synapse/util/caches/descriptors.py
index 5ac2530a6a..0e8da27f53 100644
--- a/synapse/util/caches/descriptors.py
+++ b/synapse/util/caches/descriptors.py
@@ -438,7 +438,7 @@ class CacheDescriptor(_CacheDescriptorBase):
                 if isinstance(cached_result_d, ObservableDeferred):
                     observer = cached_result_d.observe()
                 else:
-                    observer = cached_result_d
+                    observer = defer.succeed(cached_result_d)
 
             except KeyError:
                 ret = defer.maybeDeferred(
@@ -482,9 +482,8 @@ class CacheListDescriptor(_CacheDescriptorBase):
     Given a list of keys it looks in the cache to find any hits, then passes
     the list of missing keys to the wrapped function.
 
-    Once wrapped, the function returns either a Deferred which resolves to
-    the list of results, or (if all results were cached), just the list of
-    results.
+    Once wrapped, the function returns a Deferred which resolves to the list
+    of results.
     """
 
     def __init__(
@@ -618,7 +617,7 @@ class CacheListDescriptor(_CacheDescriptorBase):
                 )
                 return make_deferred_yieldable(d)
             else:
-                return results
+                return defer.succeed(results)
 
         obj.__dict__[self.orig.__name__] = wrapped
 
diff --git a/synapse/util/metrics.py b/synapse/util/metrics.py
index 4b1bcdf23c..3286804322 100644
--- a/synapse/util/metrics.py
+++ b/synapse/util/metrics.py
@@ -119,7 +119,7 @@ class Measure(object):
         context = LoggingContext.current_context()
 
         if context != self.start_context:
-            logger.warn(
+            logger.warning(
                 "Context has unexpectedly changed from '%s' to '%s'. (%r)",
                 self.start_context,
                 context,
@@ -128,7 +128,7 @@ class Measure(object):
             return
 
         if not context:
-            logger.warn("Expected context. (%r)", self.name)
+            logger.warning("Expected context. (%r)", self.name)
             return
 
         current = context.get_resource_usage()
@@ -140,7 +140,7 @@ class Measure(object):
             block_db_txn_duration.labels(self.name).inc(usage.db_txn_duration_sec)
             block_db_sched_duration.labels(self.name).inc(usage.db_sched_duration_sec)
         except ValueError:
-            logger.warn(
+            logger.warning(
                 "Failed to save metrics! OLD: %r, NEW: %r", self.start_usage, current
             )
 
diff --git a/synapse/util/rlimit.py b/synapse/util/rlimit.py
index 6c0f2bb0cf..207cd17c2a 100644
--- a/synapse/util/rlimit.py
+++ b/synapse/util/rlimit.py
@@ -33,4 +33,4 @@ def change_resource_limit(soft_file_no):
             resource.RLIMIT_CORE, (resource.RLIM_INFINITY, resource.RLIM_INFINITY)
         )
     except (ValueError, resource.error) as e:
-        logger.warn("Failed to set file or core limit: %s", e)
+        logger.warning("Failed to set file or core limit: %s", e)
diff --git a/synapse/util/versionstring.py b/synapse/util/versionstring.py
index fa404b9d75..ab7d03af3a 100644
--- a/synapse/util/versionstring.py
+++ b/synapse/util/versionstring.py
@@ -42,6 +42,7 @@ def get_version_string(module):
     try:
         null = open(os.devnull, "w")
         cwd = os.path.dirname(os.path.abspath(module.__file__))
+
         try:
             git_branch = (
                 subprocess.check_output(
@@ -51,7 +52,8 @@ def get_version_string(module):
                 .decode("ascii")
             )
             git_branch = "b=" + git_branch
-        except subprocess.CalledProcessError:
+        except (subprocess.CalledProcessError, FileNotFoundError):
+            # FileNotFoundError can arise when git is not installed
             git_branch = ""
 
         try:
@@ -63,7 +65,7 @@ def get_version_string(module):
                 .decode("ascii")
             )
             git_tag = "t=" + git_tag
-        except subprocess.CalledProcessError:
+        except (subprocess.CalledProcessError, FileNotFoundError):
             git_tag = ""
 
         try:
@@ -74,7 +76,7 @@ def get_version_string(module):
                 .strip()
                 .decode("ascii")
             )
-        except subprocess.CalledProcessError:
+        except (subprocess.CalledProcessError, FileNotFoundError):
             git_commit = ""
 
         try:
@@ -89,7 +91,7 @@ def get_version_string(module):
             )
 
             git_dirty = "dirty" if is_dirty else ""
-        except subprocess.CalledProcessError:
+        except (subprocess.CalledProcessError, FileNotFoundError):
             git_dirty = ""
 
         if git_branch or git_tag or git_commit or git_dirty:
diff --git a/synapse/visibility.py b/synapse/visibility.py
index bf0f1eebd8..8c843febd8 100644
--- a/synapse/visibility.py
+++ b/synapse/visibility.py
@@ -23,6 +23,7 @@ from twisted.internet import defer
 
 from synapse.api.constants import EventTypes, Membership
 from synapse.events.utils import prune_event
+from synapse.storage import Storage
 from synapse.storage.state import StateFilter
 from synapse.types import get_domain_from_id
 
@@ -43,14 +44,13 @@ MEMBERSHIP_PRIORITY = (
 
 @defer.inlineCallbacks
 def filter_events_for_client(
-    store, user_id, events, is_peeking=False, always_include_ids=frozenset()
+    storage: Storage, user_id, events, is_peeking=False, always_include_ids=frozenset()
 ):
     """
     Check which events a user is allowed to see
 
     Args:
-        store (synapse.storage.DataStore): our datastore (can also be a worker
-            store)
+        storage
         user_id(str): user id to be checked
         events(list[synapse.events.EventBase]): sequence of events to be checked
         is_peeking(bool): should be True if:
@@ -68,12 +68,12 @@ def filter_events_for_client(
     events = list(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 store.get_state_for_events(
+    event_id_to_state = yield storage.state.get_state_for_events(
         frozenset(e.event_id for e in events),
         state_filter=StateFilter.from_types(types),
     )
 
-    ignore_dict_content = yield store.get_global_account_data_by_type_for_user(
+    ignore_dict_content = yield storage.main.get_global_account_data_by_type_for_user(
         "m.ignored_user_list", user_id
     )
 
@@ -84,7 +84,7 @@ def filter_events_for_client(
         else []
     )
 
-    erased_senders = yield store.are_users_erased((e.sender for e in events))
+    erased_senders = yield storage.main.are_users_erased((e.sender for e in events))
 
     def allowed(event):
         """
@@ -213,13 +213,17 @@ def filter_events_for_client(
 
 @defer.inlineCallbacks
 def filter_events_for_server(
-    store, server_name, events, redact=True, check_history_visibility_only=False
+    storage: Storage,
+    server_name,
+    events,
+    redact=True,
+    check_history_visibility_only=False,
 ):
     """Filter a list of events based on whether given server is allowed to
     see them.
 
     Args:
-        store (DataStore)
+        storage
         server_name (str)
         events (iterable[FrozenEvent])
         redact (bool): Whether to return a redacted version of the event, or
@@ -274,7 +278,7 @@ def filter_events_for_server(
     # Lets check to see if all the events have a history visibility
     # of "shared" or "world_readable". If thats the case then we don't
     # need to check membership (as we know the server is in the room).
-    event_to_state_ids = yield store.get_state_ids_for_events(
+    event_to_state_ids = yield storage.state.get_state_ids_for_events(
         frozenset(e.event_id for e in events),
         state_filter=StateFilter.from_types(
             types=((EventTypes.RoomHistoryVisibility, ""),)
@@ -292,14 +296,14 @@ def filter_events_for_server(
     if not visibility_ids:
         all_open = True
     else:
-        event_map = yield store.get_events(visibility_ids)
+        event_map = yield storage.main.get_events(visibility_ids)
         all_open = all(
             e.content.get("history_visibility") in (None, "shared", "world_readable")
             for e in itervalues(event_map)
         )
 
     if not check_history_visibility_only:
-        erased_senders = yield store.are_users_erased((e.sender for e in events))
+        erased_senders = yield storage.main.are_users_erased((e.sender for e in events))
     else:
         # We don't want to check whether users are erased, which is equivalent
         # to no users having been erased.
@@ -328,7 +332,7 @@ def filter_events_for_server(
 
     # first, for each event we're wanting to return, get the event_ids
     # of the history vis and membership state at those events.
-    event_to_state_ids = yield store.get_state_ids_for_events(
+    event_to_state_ids = yield storage.state.get_state_ids_for_events(
         frozenset(e.event_id for e in events),
         state_filter=StateFilter.from_types(
             types=((EventTypes.RoomHistoryVisibility, ""), (EventTypes.Member, None))
@@ -358,7 +362,7 @@ def filter_events_for_server(
             return False
         return state_key[idx + 1 :] == server_name
 
-    event_map = yield store.get_events(
+    event_map = yield storage.main.get_events(
         [
             e_id
             for e_id, key in iteritems(event_id_to_state_key)