diff --git a/changelog.d/3659.feature b/changelog.d/3659.feature
new file mode 100644
index 0000000000..a5b4821c09
--- /dev/null
+++ b/changelog.d/3659.feature
@@ -0,0 +1 @@
+Support profile API endpoints on workers
diff --git a/changelog.d/3673.misc b/changelog.d/3673.misc
new file mode 100644
index 0000000000..d672111fb9
--- /dev/null
+++ b/changelog.d/3673.misc
@@ -0,0 +1 @@
+Refactor state module to support multiple room versions
diff --git a/changelog.d/3722.bugfix b/changelog.d/3722.bugfix
new file mode 100644
index 0000000000..16cbaf76cb
--- /dev/null
+++ b/changelog.d/3722.bugfix
@@ -0,0 +1 @@
+Fix error collecting prometheus metrics when run on dedicated thread due to threading concurrency issues
diff --git a/changelog.d/3726.misc b/changelog.d/3726.misc
new file mode 100644
index 0000000000..c4f66ec998
--- /dev/null
+++ b/changelog.d/3726.misc
@@ -0,0 +1 @@
+Split the state_group_cache into member and non-member state events (and so speed up LL /sync)
diff --git a/changelog.d/3727.misc b/changelog.d/3727.misc
new file mode 100644
index 0000000000..0b83220d90
--- /dev/null
+++ b/changelog.d/3727.misc
@@ -0,0 +1 @@
+Log failure to authenticate remote servers as warnings (without stack traces)
diff --git a/changelog.d/3732.bugfix b/changelog.d/3732.bugfix
new file mode 100644
index 0000000000..638b6334b0
--- /dev/null
+++ b/changelog.d/3732.bugfix
@@ -0,0 +1 @@
+Fix bug introduced in v0.33.3rc1 which made the ToS give a 500 error
\ No newline at end of file
diff --git a/changelog.d/3735.misc b/changelog.d/3735.misc
new file mode 100644
index 0000000000..f17004be71
--- /dev/null
+++ b/changelog.d/3735.misc
@@ -0,0 +1 @@
+Fix minor spelling error in federation client documentation.
diff --git a/docs/workers.rst b/docs/workers.rst
index aec319dd84..81146a211f 100644
--- a/docs/workers.rst
+++ b/docs/workers.rst
@@ -265,6 +265,7 @@ Handles some event creation. It can handle REST endpoints matching::
     ^/_matrix/client/(api/v1|r0|unstable)/rooms/.*/send
     ^/_matrix/client/(api/v1|r0|unstable)/rooms/.*/(join|invite|leave|ban|unban|kick)$
     ^/_matrix/client/(api/v1|r0|unstable)/join/
+    ^/_matrix/client/(api/v1|r0|unstable)/profile/
 
 It will create events locally and then send them on to the main synapse
 instance to be persisted and handled.
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index b0da506f6d..912bf024bf 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -97,9 +97,14 @@ class ThirdPartyEntityKind(object):
     LOCATION = "location"
 
 
+class RoomVersions(object):
+    V1 = "1"
+    VDH_TEST = "vdh-test-version"
+
+
 # the version we will give rooms which are created on this server
-DEFAULT_ROOM_VERSION = "1"
+DEFAULT_ROOM_VERSION = RoomVersions.V1
 
 # vdh-test-version is a placeholder to get room versioning support working and tested
 # until we have a working v2.
-KNOWN_ROOM_VERSIONS = {"1", "vdh-test-version"}
+KNOWN_ROOM_VERSIONS = {RoomVersions.V1, RoomVersions.VDH_TEST}
diff --git a/synapse/app/event_creator.py b/synapse/app/event_creator.py
index 03d39968a8..a34c89fa99 100644
--- a/synapse/app/event_creator.py
+++ b/synapse/app/event_creator.py
@@ -45,6 +45,11 @@ from synapse.replication.slave.storage.registration import SlavedRegistrationSto
 from synapse.replication.slave.storage.room import RoomStore
 from synapse.replication.slave.storage.transactions import SlavedTransactionStore
 from synapse.replication.tcp.client import ReplicationClientHandler
+from synapse.rest.client.v1.profile import (
+    ProfileAvatarURLRestServlet,
+    ProfileDisplaynameRestServlet,
+    ProfileRestServlet,
+)
 from synapse.rest.client.v1.room import (
     JoinRoomAliasServlet,
     RoomMembershipRestServlet,
@@ -53,6 +58,7 @@ from synapse.rest.client.v1.room import (
 )
 from synapse.server import HomeServer
 from synapse.storage.engines import create_engine
+from synapse.storage.user_directory import UserDirectoryStore
 from synapse.util.httpresourcetree import create_resource_tree
 from synapse.util.logcontext import LoggingContext
 from synapse.util.manhole import manhole
@@ -62,6 +68,9 @@ logger = logging.getLogger("synapse.app.event_creator")
 
 
 class EventCreatorSlavedStore(
+    # FIXME(#3714): We need to add UserDirectoryStore as we write directly
+    # rather than going via the correct worker.
+    UserDirectoryStore,
     DirectoryStore,
     SlavedTransactionStore,
     SlavedProfileStore,
@@ -101,6 +110,9 @@ class EventCreatorServer(HomeServer):
                     RoomMembershipRestServlet(self).register(resource)
                     RoomStateEventRestServlet(self).register(resource)
                     JoinRoomAliasServlet(self).register(resource)
+                    ProfileAvatarURLRestServlet(self).register(resource)
+                    ProfileDisplaynameRestServlet(self).register(resource)
+                    ProfileRestServlet(self).register(resource)
                     resources.update({
                         "/_matrix/client/r0": resource,
                         "/_matrix/client/unstable": resource,
diff --git a/synapse/crypto/keyclient.py b/synapse/crypto/keyclient.py
index c20a32096a..e94400b8e2 100644
--- a/synapse/crypto/keyclient.py
+++ b/synapse/crypto/keyclient.py
@@ -18,7 +18,9 @@ import logging
 from canonicaljson import json
 
 from twisted.internet import defer, reactor
+from twisted.internet.error import ConnectError
 from twisted.internet.protocol import Factory
+from twisted.names.error import DomainError
 from twisted.web.http import HTTPClient
 
 from synapse.http.endpoint import matrix_federation_endpoint
@@ -47,12 +49,14 @@ def fetch_server_key(server_name, tls_client_options_factory, path=KEY_API_V1):
                 server_response, server_certificate = yield protocol.remote_key
                 defer.returnValue((server_response, server_certificate))
         except SynapseKeyClientError as e:
-            logger.exception("Error getting key for %r" % (server_name,))
+            logger.warn("Error getting key for %r: %s", server_name, e)
             if e.status.startswith("4"):
                 # Don't retry for 4xx responses.
                 raise IOError("Cannot get key for %r" % server_name)
+        except (ConnectError, DomainError) as e:
+            logger.warn("Error getting key for %r: %s", server_name, e)
         except Exception as e:
-            logger.exception(e)
+            logger.exception("Error getting key for %r", server_name)
     raise IOError("Cannot get key for %r" % server_name)
 
 
diff --git a/synapse/federation/transport/client.py b/synapse/federation/transport/client.py
index b4fbe2c9d5..1054441ca5 100644
--- a/synapse/federation/transport/client.py
+++ b/synapse/federation/transport/client.py
@@ -106,7 +106,7 @@ class TransportLayerClient(object):
             dest (str)
             room_id (str)
             event_tuples (list)
-            limt (int)
+            limit (int)
 
         Returns:
             Deferred: Results in a dict received from the remote homeserver.
diff --git a/synapse/federation/transport/server.py b/synapse/federation/transport/server.py
index 77969a4f38..7a993fd1cf 100644
--- a/synapse/federation/transport/server.py
+++ b/synapse/federation/transport/server.py
@@ -261,10 +261,10 @@ class BaseFederationServlet(object):
             except NoAuthenticationError:
                 origin = None
                 if self.REQUIRE_AUTH:
-                    logger.exception("authenticate_request failed")
+                    logger.warn("authenticate_request failed: missing authentication")
                     raise
-            except Exception:
-                logger.exception("authenticate_request failed")
+            except Exception as e:
+                logger.warn("authenticate_request failed: %s", e)
                 raise
 
             if origin:
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 3dd107a285..0ebf0fd188 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -291,8 +291,9 @@ class FederationHandler(BaseHandler):
                             ev_ids, get_prev_content=False, check_redacted=False
                         )
 
+                    room_version = yield self.store.get_room_version(pdu.room_id)
                     state_map = yield resolve_events_with_factory(
-                        state_groups, {pdu.event_id: pdu}, fetch
+                        room_version, state_groups, {pdu.event_id: pdu}, fetch
                     )
 
                     state = (yield self.store.get_events(state_map.values())).values()
@@ -1828,7 +1829,10 @@ class FederationHandler(BaseHandler):
                     (d.type, d.state_key): d for d in different_events if d
                 })
 
+                room_version = yield self.store.get_room_version(event.room_id)
+
                 new_state = self.state_handler.resolve_events(
+                    room_version,
                     [list(local_view.values()), list(remote_view.values())],
                     event
                 )
diff --git a/synapse/handlers/profile.py b/synapse/handlers/profile.py
index 9af2e8f869..75b8b7ce6a 100644
--- a/synapse/handlers/profile.py
+++ b/synapse/handlers/profile.py
@@ -32,12 +32,16 @@ from ._base import BaseHandler
 logger = logging.getLogger(__name__)
 
 
-class ProfileHandler(BaseHandler):
-    PROFILE_UPDATE_MS = 60 * 1000
-    PROFILE_UPDATE_EVERY_MS = 24 * 60 * 60 * 1000
+class BaseProfileHandler(BaseHandler):
+    """Handles fetching and updating user profile information.
+
+    BaseProfileHandler can be instantiated directly on workers and will
+    delegate to master when necessary. The master process should use the
+    subclass MasterProfileHandler
+    """
 
     def __init__(self, hs):
-        super(ProfileHandler, self).__init__(hs)
+        super(BaseProfileHandler, self).__init__(hs)
 
         self.federation = hs.get_federation_client()
         hs.get_federation_registry().register_query_handler(
@@ -46,11 +50,6 @@ class ProfileHandler(BaseHandler):
 
         self.user_directory_handler = hs.get_user_directory_handler()
 
-        if hs.config.worker_app is None:
-            self.clock.looping_call(
-                self._start_update_remote_profile_cache, self.PROFILE_UPDATE_MS,
-            )
-
     @defer.inlineCallbacks
     def get_profile(self, user_id):
         target_user = UserID.from_string(user_id)
@@ -282,6 +281,20 @@ class ProfileHandler(BaseHandler):
                     room_id, str(e.message)
                 )
 
+
+class MasterProfileHandler(BaseProfileHandler):
+    PROFILE_UPDATE_MS = 60 * 1000
+    PROFILE_UPDATE_EVERY_MS = 24 * 60 * 60 * 1000
+
+    def __init__(self, hs):
+        super(MasterProfileHandler, self).__init__(hs)
+
+        assert hs.config.worker_app is None
+
+        self.clock.looping_call(
+            self._start_update_remote_profile_cache, self.PROFILE_UPDATE_MS,
+        )
+
     def _start_update_remote_profile_cache(self):
         return run_as_background_process(
             "Update remote profile", self._update_remote_profile_cache,
diff --git a/synapse/handlers/room_member.py b/synapse/handlers/room_member.py
index 0d09926c9f..5a587ec7b5 100644
--- a/synapse/handlers/room_member.py
+++ b/synapse/handlers/room_member.py
@@ -364,6 +364,7 @@ class RoomMemberHandler(object):
         latest_event_ids = (
             event_id for (event_id, _, _) in prev_events_and_hashes
         )
+
         current_state_ids = yield self.state_handler.get_current_state_ids(
             room_id, latest_event_ids=latest_event_ids,
         )
diff --git a/synapse/handlers/user_directory.py b/synapse/handlers/user_directory.py
index 37dda64587..d8413d6aa7 100644
--- a/synapse/handlers/user_directory.py
+++ b/synapse/handlers/user_directory.py
@@ -119,6 +119,8 @@ class UserDirectoryHandler(object):
         """Called to update index of our local user profiles when they change
         irrespective of any rooms the user may be in.
         """
+        # FIXME(#3714): We should probably do this in the same worker as all
+        # the other changes.
         yield self.store.update_profile_in_user_dir(
             user_id, profile.display_name, profile.avatar_url, None,
         )
@@ -127,6 +129,8 @@ class UserDirectoryHandler(object):
     def handle_user_deactivated(self, user_id):
         """Called when a user ID is deactivated
         """
+        # FIXME(#3714): We should probably do this in the same worker as all
+        # the other changes.
         yield self.store.remove_from_user_dir(user_id)
         yield self.store.remove_from_user_in_public_room(user_id)
 
diff --git a/synapse/http/request_metrics.py b/synapse/http/request_metrics.py
index 588e280571..72c2654678 100644
--- a/synapse/http/request_metrics.py
+++ b/synapse/http/request_metrics.py
@@ -15,6 +15,7 @@
 # limitations under the License.
 
 import logging
+import threading
 
 from prometheus_client.core import Counter, Histogram
 
@@ -111,6 +112,9 @@ in_flight_requests_db_sched_duration = Counter(
 # The set of all in flight requests, set[RequestMetrics]
 _in_flight_requests = set()
 
+# Protects the _in_flight_requests set from concurrent accesss
+_in_flight_requests_lock = threading.Lock()
+
 
 def _get_in_flight_counts():
     """Returns a count of all in flight requests by (method, server_name)
@@ -120,7 +124,8 @@ def _get_in_flight_counts():
     """
     # Cast to a list to prevent it changing while the Prometheus
     # thread is collecting metrics
-    reqs = list(_in_flight_requests)
+    with _in_flight_requests_lock:
+        reqs = list(_in_flight_requests)
 
     for rm in reqs:
         rm.update_metrics()
@@ -154,10 +159,12 @@ class RequestMetrics(object):
         # to the "in flight" metrics.
         self._request_stats = self.start_context.get_resource_usage()
 
-        _in_flight_requests.add(self)
+        with _in_flight_requests_lock:
+            _in_flight_requests.add(self)
 
     def stop(self, time_sec, request):
-        _in_flight_requests.discard(self)
+        with _in_flight_requests_lock:
+            _in_flight_requests.discard(self)
 
         context = LoggingContext.current_context()
 
diff --git a/synapse/metrics/background_process_metrics.py b/synapse/metrics/background_process_metrics.py
index ce678d5f75..167167be0a 100644
--- a/synapse/metrics/background_process_metrics.py
+++ b/synapse/metrics/background_process_metrics.py
@@ -13,6 +13,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import threading
+
 import six
 
 from prometheus_client.core import REGISTRY, Counter, GaugeMetricFamily
@@ -78,6 +80,9 @@ _background_process_counts = dict()  # type: dict[str, int]
 # of process descriptions that no longer have any active processes.
 _background_processes = dict()  # type: dict[str, set[_BackgroundProcess]]
 
+# A lock that covers the above dicts
+_bg_metrics_lock = threading.Lock()
+
 
 class _Collector(object):
     """A custom metrics collector for the background process metrics.
@@ -92,7 +97,11 @@ class _Collector(object):
             labels=["name"],
         )
 
-        for desc, processes in six.iteritems(_background_processes):
+        # We copy the dict so that it doesn't change from underneath us
+        with _bg_metrics_lock:
+            _background_processes_copy = dict(_background_processes)
+
+        for desc, processes in six.iteritems(_background_processes_copy):
             background_process_in_flight_count.add_metric(
                 (desc,), len(processes),
             )
@@ -167,19 +176,26 @@ def run_as_background_process(desc, func, *args, **kwargs):
     """
     @defer.inlineCallbacks
     def run():
-        count = _background_process_counts.get(desc, 0)
-        _background_process_counts[desc] = count + 1
+        with _bg_metrics_lock:
+            count = _background_process_counts.get(desc, 0)
+            _background_process_counts[desc] = count + 1
+
         _background_process_start_count.labels(desc).inc()
 
         with LoggingContext(desc) as context:
             context.request = "%s-%i" % (desc, count)
             proc = _BackgroundProcess(desc, context)
-            _background_processes.setdefault(desc, set()).add(proc)
+
+            with _bg_metrics_lock:
+                _background_processes.setdefault(desc, set()).add(proc)
+
             try:
                 yield func(*args, **kwargs)
             finally:
                 proc.update_metrics()
-                _background_processes[desc].remove(proc)
+
+                with _bg_metrics_lock:
+                    _background_processes[desc].remove(proc)
 
     with PreserveLoggingContext():
         return run()
diff --git a/synapse/rest/consent/consent_resource.py b/synapse/rest/consent/consent_resource.py
index 52954ada12..7362e1858d 100644
--- a/synapse/rest/consent/consent_resource.py
+++ b/synapse/rest/consent/consent_resource.py
@@ -140,7 +140,7 @@ class ConsentResource(Resource):
         version = parse_string(request, "v",
                                default=self._default_consent_version)
         username = parse_string(request, "u", required=True)
-        userhmac = parse_string(request, "h", required=True)
+        userhmac = parse_string(request, "h", required=True, encoding=None)
 
         self._check_hash(username, userhmac)
 
diff --git a/synapse/server.py b/synapse/server.py
index 26228d8c72..a6fbc6ec0c 100644
--- a/synapse/server.py
+++ b/synapse/server.py
@@ -56,7 +56,7 @@ from synapse.handlers.initial_sync import InitialSyncHandler
 from synapse.handlers.message import EventCreationHandler, MessageHandler
 from synapse.handlers.pagination import PaginationHandler
 from synapse.handlers.presence import PresenceHandler
-from synapse.handlers.profile import ProfileHandler
+from synapse.handlers.profile import BaseProfileHandler, MasterProfileHandler
 from synapse.handlers.read_marker import ReadMarkerHandler
 from synapse.handlers.receipts import ReceiptsHandler
 from synapse.handlers.room import RoomContextHandler, RoomCreationHandler
@@ -308,7 +308,10 @@ class HomeServer(object):
         return InitialSyncHandler(self)
 
     def build_profile_handler(self):
-        return ProfileHandler(self)
+        if self.config.worker_app:
+            return BaseProfileHandler(self)
+        else:
+            return MasterProfileHandler(self)
 
     def build_event_creation_handler(self):
         return EventCreationHandler(self)
diff --git a/synapse/state.py b/synapse/state/__init__.py
similarity index 70%
rename from synapse/state.py
rename to synapse/state/__init__.py
index 0f2bedb694..b34970e4d1 100644
--- a/synapse/state.py
+++ b/synapse/state/__init__.py
@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 # Copyright 2014-2016 OpenMarket Ltd
+# Copyright 2018 New Vector Ltd
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -13,21 +14,18 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-
-import hashlib
 import logging
 from collections import namedtuple
 
-from six import iteritems, iterkeys, itervalues
+from six import iteritems, itervalues
 
 from frozendict import frozendict
 
 from twisted.internet import defer
 
-from synapse import event_auth
-from synapse.api.constants import EventTypes
-from synapse.api.errors import AuthError
+from synapse.api.constants import EventTypes, RoomVersions
 from synapse.events.snapshot import EventContext
+from synapse.state import v1
 from synapse.util.async_helpers import Linearizer
 from synapse.util.caches import get_cache_factor_for
 from synapse.util.caches.expiringcache import ExpiringCache
@@ -264,6 +262,7 @@ class StateHandler(object):
             defer.returnValue(context)
 
         logger.debug("calling resolve_state_groups from compute_event_context")
+
         entry = yield self.resolve_state_groups_for_events(
             event.room_id, [e for e, _ in event.prev_events],
         )
@@ -338,8 +337,11 @@ class StateHandler(object):
         event, resolves conflicts between them and returns them.
 
         Args:
-            room_id (str):
-            event_ids (list[str]):
+            room_id (str)
+            event_ids (list[str])
+            explicit_room_version (str|None): If set uses the the given room
+                version to choose the resolution algorithm. If None, then
+                checks the database for room version.
 
         Returns:
             Deferred[_StateCacheEntry]: resolved state
@@ -353,7 +355,12 @@ class StateHandler(object):
             room_id, event_ids
         )
 
-        if len(state_groups_ids) == 1:
+        if len(state_groups_ids) == 0:
+            defer.returnValue(_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)
@@ -365,8 +372,11 @@ class StateHandler(object):
                 delta_ids=delta_ids,
             ))
 
+        room_version = yield self.store.get_room_version(room_id)
+
         result = yield self._state_resolution_handler.resolve_state_groups(
-            room_id, state_groups_ids, None, self._state_map_factory,
+            room_id, room_version, state_groups_ids, None,
+            self._state_map_factory,
         )
         defer.returnValue(result)
 
@@ -375,7 +385,7 @@ class StateHandler(object):
             ev_ids, get_prev_content=False, check_redacted=False,
         )
 
-    def resolve_events(self, state_sets, event):
+    def resolve_events(self, room_version, state_sets, event):
         logger.info(
             "Resolving state for %s with %d groups", event.room_id, len(state_sets)
         )
@@ -391,7 +401,9 @@ class StateHandler(object):
         }
 
         with Measure(self.clock, "state._resolve_events"):
-            new_state = resolve_events_with_state_map(state_set_ids, state_map)
+            new_state = resolve_events_with_state_map(
+                room_version, state_set_ids, state_map,
+            )
 
         new_state = {
             key: state_map[ev_id] for key, ev_id in iteritems(new_state)
@@ -430,7 +442,7 @@ class StateResolutionHandler(object):
     @defer.inlineCallbacks
     @log_function
     def resolve_state_groups(
-        self, room_id, state_groups_ids, event_map, state_map_factory,
+        self, room_id, room_version, state_groups_ids, event_map, state_map_factory,
     ):
         """Resolves conflicts between a set of state groups
 
@@ -439,6 +451,7 @@ class StateResolutionHandler(object):
 
         Args:
             room_id (str): room we are resolving for (used for logging)
+            room_version (str): version of the room
             state_groups_ids (dict[int, dict[(str, str), str]]):
                  map from state group id to the state in that state group
                 (where 'state' is a map from state key to event id)
@@ -492,6 +505,7 @@ class StateResolutionHandler(object):
                 logger.info("Resolving conflicted state for %r", room_id)
                 with Measure(self.clock, "state._resolve_events"):
                     new_state = yield resolve_events_with_factory(
+                        room_version,
                         list(itervalues(state_groups_ids)),
                         event_map=event_map,
                         state_map_factory=state_map_factory,
@@ -575,16 +589,10 @@ def _make_state_cache_entry(
     )
 
 
-def _ordered_events(events):
-    def key_func(e):
-        return -int(e.depth), hashlib.sha1(e.event_id.encode('ascii')).hexdigest()
-
-    return sorted(events, key=key_func)
-
-
-def resolve_events_with_state_map(state_sets, state_map):
+def resolve_events_with_state_map(room_version, state_sets, state_map):
     """
     Args:
+        room_version(str): Version of the room
         state_sets(list): List of dicts of (type, state_key) -> event_id,
             which are the different state groups to resolve.
         state_map(dict): a dict from event_id to event, for all events in
@@ -594,75 +602,23 @@ def resolve_events_with_state_map(state_sets, state_map):
         dict[(str, str), str]:
             a map from (type, state_key) to event_id.
     """
-    if len(state_sets) == 1:
-        return state_sets[0]
-
-    unconflicted_state, conflicted_state = _seperate(
-        state_sets,
-    )
-
-    auth_events = _create_auth_events_from_maps(
-        unconflicted_state, conflicted_state, state_map
-    )
-
-    return _resolve_with_state(
-        unconflicted_state, conflicted_state, auth_events, state_map
-    )
+    if room_version in (RoomVersions.V1, RoomVersions.VDH_TEST,):
+        return v1.resolve_events_with_state_map(
+            state_sets, state_map,
+        )
+    else:
+        # This should only happen if we added a version but forgot to add it to
+        # the list above.
+        raise Exception(
+            "No state resolution algorithm defined for version %r" % (room_version,)
+        )
 
 
-def _seperate(state_sets):
-    """Takes the state_sets and figures out which keys are conflicted and
-    which aren't. i.e., which have multiple different event_ids associated
-    with them in different state sets.
-
-    Args:
-        state_sets(iterable[dict[(str, str), str]]):
-            List of dicts of (type, state_key) -> event_id, which are the
-            different state groups to resolve.
-
-    Returns:
-        (dict[(str, str), str], dict[(str, str), set[str]]):
-            A tuple of (unconflicted_state, conflicted_state), where:
-
-            unconflicted_state is a dict mapping (type, state_key)->event_id
-            for unconflicted state keys.
-
-            conflicted_state is a dict mapping (type, state_key) to a set of
-            event ids for conflicted state keys.
-    """
-    state_set_iterator = iter(state_sets)
-    unconflicted_state = dict(next(state_set_iterator))
-    conflicted_state = {}
-
-    for state_set in state_set_iterator:
-        for key, value in iteritems(state_set):
-            # Check if there is an unconflicted entry for the state key.
-            unconflicted_value = unconflicted_state.get(key)
-            if unconflicted_value is None:
-                # There isn't an unconflicted entry so check if there is a
-                # conflicted entry.
-                ls = conflicted_state.get(key)
-                if ls is None:
-                    # There wasn't a conflicted entry so haven't seen this key before.
-                    # Therefore it isn't conflicted yet.
-                    unconflicted_state[key] = value
-                else:
-                    # This key is already conflicted, add our value to the conflict set.
-                    ls.add(value)
-            elif unconflicted_value != value:
-                # If the unconflicted value is not the same as our value then we
-                # have a new conflict. So move the key from the unconflicted_state
-                # to the conflicted state.
-                conflicted_state[key] = {value, unconflicted_value}
-                unconflicted_state.pop(key, None)
-
-    return unconflicted_state, conflicted_state
-
-
-@defer.inlineCallbacks
-def resolve_events_with_factory(state_sets, event_map, state_map_factory):
+def resolve_events_with_factory(room_version, state_sets, event_map, state_map_factory):
     """
     Args:
+        room_version(str): Version of the room
+
         state_sets(list): List of dicts of (type, state_key) -> event_id,
             which are the different state groups to resolve.
 
@@ -682,185 +638,13 @@ def resolve_events_with_factory(state_sets, event_map, state_map_factory):
         Deferred[dict[(str, str), str]]:
             a map from (type, state_key) to event_id.
     """
-    if len(state_sets) == 1:
-        defer.returnValue(state_sets[0])
-
-    unconflicted_state, conflicted_state = _seperate(
-        state_sets,
-    )
-
-    needed_events = set(
-        event_id
-        for event_ids in itervalues(conflicted_state)
-        for event_id in event_ids
-    )
-    if event_map is not None:
-        needed_events -= set(iterkeys(event_map))
-
-    logger.info("Asking for %d conflicted events", len(needed_events))
-
-    # dict[str, FrozenEvent]: a map from state event id to event. Only includes
-    # the state events which are in conflict (and those in event_map)
-    state_map = yield state_map_factory(needed_events)
-    if event_map is not None:
-        state_map.update(event_map)
-
-    # get the ids of the auth events which allow us to authenticate the
-    # conflicted state, picking only from the unconflicting state.
-    #
-    # dict[(str, str), str]: a map from state key to event id
-    auth_events = _create_auth_events_from_maps(
-        unconflicted_state, conflicted_state, state_map
-    )
-
-    new_needed_events = set(itervalues(auth_events))
-    new_needed_events -= needed_events
-    if event_map is not None:
-        new_needed_events -= set(iterkeys(event_map))
-
-    logger.info("Asking for %d auth events", len(new_needed_events))
-
-    state_map_new = yield state_map_factory(new_needed_events)
-    state_map.update(state_map_new)
-
-    defer.returnValue(_resolve_with_state(
-        unconflicted_state, conflicted_state, auth_events, state_map
-    ))
-
-
-def _create_auth_events_from_maps(unconflicted_state, conflicted_state, state_map):
-    auth_events = {}
-    for event_ids in itervalues(conflicted_state):
-        for event_id in event_ids:
-            if event_id in state_map:
-                keys = event_auth.auth_types_for_event(state_map[event_id])
-                for key in keys:
-                    if key not in auth_events:
-                        event_id = unconflicted_state.get(key, None)
-                        if event_id:
-                            auth_events[key] = event_id
-    return auth_events
-
-
-def _resolve_with_state(unconflicted_state_ids, conflicted_state_ids, auth_event_ids,
-                        state_map):
-    conflicted_state = {}
-    for key, event_ids in iteritems(conflicted_state_ids):
-        events = [state_map[ev_id] for ev_id in event_ids if ev_id in state_map]
-        if len(events) > 1:
-            conflicted_state[key] = events
-        elif len(events) == 1:
-            unconflicted_state_ids[key] = events[0].event_id
-
-    auth_events = {
-        key: state_map[ev_id]
-        for key, ev_id in iteritems(auth_event_ids)
-        if ev_id in state_map
-    }
-
-    try:
-        resolved_state = _resolve_state_events(
-            conflicted_state, auth_events
+    if room_version in (RoomVersions.V1, RoomVersions.VDH_TEST,):
+        return v1.resolve_events_with_factory(
+            state_sets, event_map, state_map_factory,
+        )
+    else:
+        # This should only happen if we added a version but forgot to add it to
+        # the list above.
+        raise Exception(
+            "No state resolution algorithm defined for version %r" % (room_version,)
         )
-    except Exception:
-        logger.exception("Failed to resolve state")
-        raise
-
-    new_state = unconflicted_state_ids
-    for key, event in iteritems(resolved_state):
-        new_state[key] = event.event_id
-
-    return new_state
-
-
-def _resolve_state_events(conflicted_state, auth_events):
-    """ This is where we actually decide which of the conflicted state to
-    use.
-
-    We resolve conflicts in the following order:
-        1. power levels
-        2. join rules
-        3. memberships
-        4. other events.
-    """
-    resolved_state = {}
-    if POWER_KEY in conflicted_state:
-        events = conflicted_state[POWER_KEY]
-        logger.debug("Resolving conflicted power levels %r", events)
-        resolved_state[POWER_KEY] = _resolve_auth_events(
-            events, auth_events)
-
-    auth_events.update(resolved_state)
-
-    for key, events in iteritems(conflicted_state):
-        if key[0] == EventTypes.JoinRules:
-            logger.debug("Resolving conflicted join rules %r", events)
-            resolved_state[key] = _resolve_auth_events(
-                events,
-                auth_events
-            )
-
-    auth_events.update(resolved_state)
-
-    for key, events in iteritems(conflicted_state):
-        if key[0] == EventTypes.Member:
-            logger.debug("Resolving conflicted member lists %r", events)
-            resolved_state[key] = _resolve_auth_events(
-                events,
-                auth_events
-            )
-
-    auth_events.update(resolved_state)
-
-    for key, events in iteritems(conflicted_state):
-        if key not in resolved_state:
-            logger.debug("Resolving conflicted state %r:%r", key, events)
-            resolved_state[key] = _resolve_normal_events(
-                events, auth_events
-            )
-
-    return resolved_state
-
-
-def _resolve_auth_events(events, auth_events):
-    reverse = [i for i in reversed(_ordered_events(events))]
-
-    auth_keys = set(
-        key
-        for event in events
-        for key in event_auth.auth_types_for_event(event)
-    )
-
-    new_auth_events = {}
-    for key in auth_keys:
-        auth_event = auth_events.get(key, None)
-        if auth_event:
-            new_auth_events[key] = auth_event
-
-    auth_events = new_auth_events
-
-    prev_event = reverse[0]
-    for event in reverse[1:]:
-        auth_events[(prev_event.type, prev_event.state_key)] = prev_event
-        try:
-            # The signatures have already been checked at this point
-            event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False)
-            prev_event = event
-        except AuthError:
-            return prev_event
-
-    return event
-
-
-def _resolve_normal_events(events, auth_events):
-    for event in _ordered_events(events):
-        try:
-            # The signatures have already been checked at this point
-            event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False)
-            return event
-        except AuthError:
-            pass
-
-    # Use the last event (the one with the least depth) if they all fail
-    # the auth check.
-    return event
diff --git a/synapse/state/v1.py b/synapse/state/v1.py
new file mode 100644
index 0000000000..3a1f7054a1
--- /dev/null
+++ b/synapse/state/v1.py
@@ -0,0 +1,321 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector Ltd
+#
+# 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 hashlib
+import logging
+
+from six import iteritems, iterkeys, itervalues
+
+from twisted.internet import defer
+
+from synapse import event_auth
+from synapse.api.constants import EventTypes
+from synapse.api.errors import AuthError
+
+logger = logging.getLogger(__name__)
+
+
+POWER_KEY = (EventTypes.PowerLevels, "")
+
+
+def resolve_events_with_state_map(state_sets, state_map):
+    """
+    Args:
+        state_sets(list): List of dicts of (type, state_key) -> event_id,
+            which are the different state groups to resolve.
+        state_map(dict): a dict from event_id to event, for all events in
+            state_sets.
+
+    Returns
+        dict[(str, str), str]:
+            a map from (type, state_key) to event_id.
+    """
+    if len(state_sets) == 1:
+        return state_sets[0]
+
+    unconflicted_state, conflicted_state = _seperate(
+        state_sets,
+    )
+
+    auth_events = _create_auth_events_from_maps(
+        unconflicted_state, conflicted_state, state_map
+    )
+
+    return _resolve_with_state(
+        unconflicted_state, conflicted_state, auth_events, state_map
+    )
+
+
+@defer.inlineCallbacks
+def resolve_events_with_factory(state_sets, event_map, state_map_factory):
+    """
+    Args:
+        state_sets(list): List of dicts of (type, state_key) -> event_id,
+            which are the different state groups to resolve.
+
+        event_map(dict[str,FrozenEvent]|None):
+            a dict from event_id to event, for any events that we happen to
+            have in flight (eg, those currently being persisted). This will be
+            used as a starting point fof finding the state we need; any missing
+            events will be requested via state_map_factory.
+
+            If None, all events will be fetched via state_map_factory.
+
+        state_map_factory(func): will be called
+            with a list of event_ids that are needed, and should return with
+            a Deferred of dict of event_id to event.
+
+    Returns
+        Deferred[dict[(str, str), str]]:
+            a map from (type, state_key) to event_id.
+    """
+    if len(state_sets) == 1:
+        defer.returnValue(state_sets[0])
+
+    unconflicted_state, conflicted_state = _seperate(
+        state_sets,
+    )
+
+    needed_events = set(
+        event_id
+        for event_ids in itervalues(conflicted_state)
+        for event_id in event_ids
+    )
+    if event_map is not None:
+        needed_events -= set(iterkeys(event_map))
+
+    logger.info("Asking for %d conflicted events", len(needed_events))
+
+    # dict[str, FrozenEvent]: a map from state event id to event. Only includes
+    # the state events which are in conflict (and those in event_map)
+    state_map = yield state_map_factory(needed_events)
+    if event_map is not None:
+        state_map.update(event_map)
+
+    # get the ids of the auth events which allow us to authenticate the
+    # conflicted state, picking only from the unconflicting state.
+    #
+    # dict[(str, str), str]: a map from state key to event id
+    auth_events = _create_auth_events_from_maps(
+        unconflicted_state, conflicted_state, state_map
+    )
+
+    new_needed_events = set(itervalues(auth_events))
+    new_needed_events -= needed_events
+    if event_map is not None:
+        new_needed_events -= set(iterkeys(event_map))
+
+    logger.info("Asking for %d auth events", len(new_needed_events))
+
+    state_map_new = yield state_map_factory(new_needed_events)
+    state_map.update(state_map_new)
+
+    defer.returnValue(_resolve_with_state(
+        unconflicted_state, conflicted_state, auth_events, state_map
+    ))
+
+
+def _seperate(state_sets):
+    """Takes the state_sets and figures out which keys are conflicted and
+    which aren't. i.e., which have multiple different event_ids associated
+    with them in different state sets.
+
+    Args:
+        state_sets(iterable[dict[(str, str), str]]):
+            List of dicts of (type, state_key) -> event_id, which are the
+            different state groups to resolve.
+
+    Returns:
+        (dict[(str, str), str], dict[(str, str), set[str]]):
+            A tuple of (unconflicted_state, conflicted_state), where:
+
+            unconflicted_state is a dict mapping (type, state_key)->event_id
+            for unconflicted state keys.
+
+            conflicted_state is a dict mapping (type, state_key) to a set of
+            event ids for conflicted state keys.
+    """
+    state_set_iterator = iter(state_sets)
+    unconflicted_state = dict(next(state_set_iterator))
+    conflicted_state = {}
+
+    for state_set in state_set_iterator:
+        for key, value in iteritems(state_set):
+            # Check if there is an unconflicted entry for the state key.
+            unconflicted_value = unconflicted_state.get(key)
+            if unconflicted_value is None:
+                # There isn't an unconflicted entry so check if there is a
+                # conflicted entry.
+                ls = conflicted_state.get(key)
+                if ls is None:
+                    # There wasn't a conflicted entry so haven't seen this key before.
+                    # Therefore it isn't conflicted yet.
+                    unconflicted_state[key] = value
+                else:
+                    # This key is already conflicted, add our value to the conflict set.
+                    ls.add(value)
+            elif unconflicted_value != value:
+                # If the unconflicted value is not the same as our value then we
+                # have a new conflict. So move the key from the unconflicted_state
+                # to the conflicted state.
+                conflicted_state[key] = {value, unconflicted_value}
+                unconflicted_state.pop(key, None)
+
+    return unconflicted_state, conflicted_state
+
+
+def _create_auth_events_from_maps(unconflicted_state, conflicted_state, state_map):
+    auth_events = {}
+    for event_ids in itervalues(conflicted_state):
+        for event_id in event_ids:
+            if event_id in state_map:
+                keys = event_auth.auth_types_for_event(state_map[event_id])
+                for key in keys:
+                    if key not in auth_events:
+                        event_id = unconflicted_state.get(key, None)
+                        if event_id:
+                            auth_events[key] = event_id
+    return auth_events
+
+
+def _resolve_with_state(unconflicted_state_ids, conflicted_state_ids, auth_event_ids,
+                        state_map):
+    conflicted_state = {}
+    for key, event_ids in iteritems(conflicted_state_ids):
+        events = [state_map[ev_id] for ev_id in event_ids if ev_id in state_map]
+        if len(events) > 1:
+            conflicted_state[key] = events
+        elif len(events) == 1:
+            unconflicted_state_ids[key] = events[0].event_id
+
+    auth_events = {
+        key: state_map[ev_id]
+        for key, ev_id in iteritems(auth_event_ids)
+        if ev_id in state_map
+    }
+
+    try:
+        resolved_state = _resolve_state_events(
+            conflicted_state, auth_events
+        )
+    except Exception:
+        logger.exception("Failed to resolve state")
+        raise
+
+    new_state = unconflicted_state_ids
+    for key, event in iteritems(resolved_state):
+        new_state[key] = event.event_id
+
+    return new_state
+
+
+def _resolve_state_events(conflicted_state, auth_events):
+    """ This is where we actually decide which of the conflicted state to
+    use.
+
+    We resolve conflicts in the following order:
+        1. power levels
+        2. join rules
+        3. memberships
+        4. other events.
+    """
+    resolved_state = {}
+    if POWER_KEY in conflicted_state:
+        events = conflicted_state[POWER_KEY]
+        logger.debug("Resolving conflicted power levels %r", events)
+        resolved_state[POWER_KEY] = _resolve_auth_events(
+            events, auth_events)
+
+    auth_events.update(resolved_state)
+
+    for key, events in iteritems(conflicted_state):
+        if key[0] == EventTypes.JoinRules:
+            logger.debug("Resolving conflicted join rules %r", events)
+            resolved_state[key] = _resolve_auth_events(
+                events,
+                auth_events
+            )
+
+    auth_events.update(resolved_state)
+
+    for key, events in iteritems(conflicted_state):
+        if key[0] == EventTypes.Member:
+            logger.debug("Resolving conflicted member lists %r", events)
+            resolved_state[key] = _resolve_auth_events(
+                events,
+                auth_events
+            )
+
+    auth_events.update(resolved_state)
+
+    for key, events in iteritems(conflicted_state):
+        if key not in resolved_state:
+            logger.debug("Resolving conflicted state %r:%r", key, events)
+            resolved_state[key] = _resolve_normal_events(
+                events, auth_events
+            )
+
+    return resolved_state
+
+
+def _resolve_auth_events(events, auth_events):
+    reverse = [i for i in reversed(_ordered_events(events))]
+
+    auth_keys = set(
+        key
+        for event in events
+        for key in event_auth.auth_types_for_event(event)
+    )
+
+    new_auth_events = {}
+    for key in auth_keys:
+        auth_event = auth_events.get(key, None)
+        if auth_event:
+            new_auth_events[key] = auth_event
+
+    auth_events = new_auth_events
+
+    prev_event = reverse[0]
+    for event in reverse[1:]:
+        auth_events[(prev_event.type, prev_event.state_key)] = prev_event
+        try:
+            # The signatures have already been checked at this point
+            event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False)
+            prev_event = event
+        except AuthError:
+            return prev_event
+
+    return event
+
+
+def _resolve_normal_events(events, auth_events):
+    for event in _ordered_events(events):
+        try:
+            # The signatures have already been checked at this point
+            event_auth.check(event, auth_events, do_sig_check=False, do_size_check=False)
+            return event
+        except AuthError:
+            pass
+
+    # Use the last event (the one with the least depth) if they all fail
+    # the auth check.
+    return event
+
+
+def _ordered_events(events):
+    def key_func(e):
+        return -int(e.depth), hashlib.sha1(e.event_id.encode('ascii')).hexdigest()
+
+    return sorted(events, key=key_func)
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 025a7fb6d9..f39c8c8461 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -705,9 +705,11 @@ class EventsStore(EventFederationStore, EventsWorkerStore, BackgroundUpdateStore
         }
 
         events_map = {ev.event_id: ev for ev, _ in events_context}
+        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, state_groups, events_map, get_events
+            room_id, room_version, state_groups, events_map, get_events
         )
 
         defer.returnValue((res.state, None))
diff --git a/synapse/storage/profile.py b/synapse/storage/profile.py
index 60295da254..88b50f33b5 100644
--- a/synapse/storage/profile.py
+++ b/synapse/storage/profile.py
@@ -71,8 +71,6 @@ class ProfileWorkerStore(SQLBaseStore):
             desc="get_from_remote_profile_cache",
         )
 
-
-class ProfileStore(ProfileWorkerStore):
     def create_profile(self, user_localpart):
         return self._simple_insert(
             table="profiles",
@@ -96,6 +94,8 @@ class ProfileStore(ProfileWorkerStore):
             desc="set_profile_avatar_url",
         )
 
+
+class ProfileStore(ProfileWorkerStore):
     def add_remote_profile_cache(self, user_id, displayname, avatar_url):
         """Ensure we are caching the remote user's profiles.
 
diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index 3378fc77d1..61013b8919 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -186,6 +186,35 @@ class RoomWorkerStore(SQLBaseStore):
             desc="is_room_blocked",
         )
 
+    @cachedInlineCallbacks(max_entries=10000)
+    def get_ratelimit_for_user(self, user_id):
+        """Check if there are any overrides for ratelimiting for the given
+        user
+
+        Args:
+            user_id (str)
+
+        Returns:
+            RatelimitOverride if there is an override, else None. If the contents
+            of RatelimitOverride are None or 0 then ratelimitng has been
+            disabled for that user entirely.
+        """
+        row = yield self._simple_select_one(
+            table="ratelimit_override",
+            keyvalues={"user_id": user_id},
+            retcols=("messages_per_second", "burst_count"),
+            allow_none=True,
+            desc="get_ratelimit_for_user",
+        )
+
+        if row:
+            defer.returnValue(RatelimitOverride(
+                messages_per_second=row["messages_per_second"],
+                burst_count=row["burst_count"],
+            ))
+        else:
+            defer.returnValue(None)
+
 
 class RoomStore(RoomWorkerStore, SearchStore):
 
@@ -469,35 +498,6 @@ class RoomStore(RoomWorkerStore, SearchStore):
             "get_all_new_public_rooms", get_all_new_public_rooms
         )
 
-    @cachedInlineCallbacks(max_entries=10000)
-    def get_ratelimit_for_user(self, user_id):
-        """Check if there are any overrides for ratelimiting for the given
-        user
-
-        Args:
-            user_id (str)
-
-        Returns:
-            RatelimitOverride if there is an override, else None. If the contents
-            of RatelimitOverride are None or 0 then ratelimitng has been
-            disabled for that user entirely.
-        """
-        row = yield self._simple_select_one(
-            table="ratelimit_override",
-            keyvalues={"user_id": user_id},
-            retcols=("messages_per_second", "burst_count"),
-            allow_none=True,
-            desc="get_ratelimit_for_user",
-        )
-
-        if row:
-            defer.returnValue(RatelimitOverride(
-                messages_per_second=row["messages_per_second"],
-                burst_count=row["burst_count"],
-            ))
-        else:
-            defer.returnValue(None)
-
     @defer.inlineCallbacks
     def block_room(self, room_id, user_id):
         yield self._simple_insert(
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index dd03c4168b..4b971efdba 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -60,8 +60,43 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
     def __init__(self, db_conn, hs):
         super(StateGroupWorkerStore, self).__init__(db_conn, hs)
 
+        # Originally the state store used a single DictionaryCache to cache the
+        # event IDs for the state types in a given state group to avoid hammering
+        # on the state_group* tables.
+        #
+        # The point of using a DictionaryCache is that it can cache a subset
+        # of the state events for a given state group (i.e. a subset of the keys for a
+        # given dict which is an entry in the cache for a given state group ID).
+        #
+        # However, this poses problems when performing complicated queries
+        # on the store - for instance: "give me all the state for this group, but
+        # limit members to this subset of users", as DictionaryCache's API isn't
+        # rich enough to say "please cache any of these fields, apart from this subset".
+        # This is problematic when lazy loading members, which requires this behaviour,
+        # as without it the cache has no choice but to speculatively load all
+        # state events for the group, which negates the efficiency being sought.
+        #
+        # Rather than overcomplicating DictionaryCache's API, we instead split the
+        # state_group_cache into two halves - one for tracking non-member events,
+        # and the other for tracking member_events.  This means that lazy loading
+        # queries can be made in a cache-friendly manner by querying both caches
+        # separately and then merging the result.  So for the example above, you
+        # would query the members cache for a specific subset of state keys
+        # (which DictionaryCache will handle efficiently and fine) and the non-members
+        # cache for all state (which DictionaryCache will similarly handle fine)
+        # and then just merge the results together.
+        #
+        # We size the non-members cache to be smaller than the members cache as the
+        # vast majority of state in Matrix (today) is member events.
+
         self._state_group_cache = DictionaryCache(
-            "*stateGroupCache*", 500000 * get_cache_factor_for("stateGroupCache")
+            "*stateGroupCache*",
+            # TODO: this hasn't been tuned yet
+            50000 * get_cache_factor_for("stateGroupCache")
+        )
+        self._state_group_members_cache = DictionaryCache(
+            "*stateGroupMembersCache*",
+            500000 * get_cache_factor_for("stateGroupMembersCache")
         )
 
     @defer.inlineCallbacks
@@ -275,7 +310,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         })
 
     @defer.inlineCallbacks
-    def _get_state_groups_from_groups(self, groups, types):
+    def _get_state_groups_from_groups(self, groups, types, members=None):
         """Returns the state groups for a given set of groups, filtering on
         types of state events.
 
@@ -284,6 +319,9 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             types (Iterable[str, str|None]|None): list of 2-tuples of the form
                 (`type`, `state_key`), where a `state_key` of `None` matches all
                 state_keys for the `type`. If None, all types are returned.
+            members (bool|None): If not None, then, in addition to any filtering
+                implied by types, the results are also filtered to only include
+                member events (if True), or to exclude member events (if False)
 
         Returns:
             dictionary state_group -> (dict of (type, state_key) -> event id)
@@ -294,14 +332,14 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         for chunk in chunks:
             res = yield self.runInteraction(
                 "_get_state_groups_from_groups",
-                self._get_state_groups_from_groups_txn, chunk, types,
+                self._get_state_groups_from_groups_txn, chunk, types, members,
             )
             results.update(res)
 
         defer.returnValue(results)
 
     def _get_state_groups_from_groups_txn(
-        self, txn, groups, types=None,
+        self, txn, groups, types=None, members=None,
     ):
         results = {group: {} for group in groups}
 
@@ -339,6 +377,11 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
                 %s
             """)
 
+            if members is True:
+                sql += " AND type = '%s'" % (EventTypes.Member,)
+            elif members is False:
+                sql += " AND type <> '%s'" % (EventTypes.Member,)
+
             # Turns out that postgres doesn't like doing a list of OR's and
             # is about 1000x slower, so we just issue a query for each specific
             # type seperately.
@@ -386,6 +429,11 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             else:
                 where_clause = ""
 
+            if members is True:
+                where_clause += " AND type = '%s'" % EventTypes.Member
+            elif members is False:
+                where_clause += " AND type <> '%s'" % EventTypes.Member
+
             # We don't use WITH RECURSIVE on sqlite3 as there are distributions
             # that ship with an sqlite3 version that doesn't support it (e.g. wheezy)
             for group in groups:
@@ -580,10 +628,11 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
         defer.returnValue({row["event_id"]: row["state_group"] for row in rows})
 
-    def _get_some_state_from_cache(self, group, types, filtered_types=None):
+    def _get_some_state_from_cache(self, cache, group, types, filtered_types=None):
         """Checks if group is in cache. See `_get_state_for_groups`
 
         Args:
+            cache(DictionaryCache): the state group cache to use
             group(int): The state group to lookup
             types(list[str, str|None]): List of 2-tuples of the form
                 (`type`, `state_key`), where a `state_key` of `None` matches all
@@ -597,11 +646,11 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         requests state from the cache, if False we need to query the DB for the
         missing state.
         """
-        is_all, known_absent, state_dict_ids = self._state_group_cache.get(group)
+        is_all, known_absent, state_dict_ids = cache.get(group)
 
         type_to_key = {}
 
-        # tracks whether any of ourrequested types are missing from the cache
+        # tracks whether any of our requested types are missing from the cache
         missing_types = False
 
         for typ, state_key in types:
@@ -648,7 +697,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
             if include(k[0], k[1])
         }, got_all
 
-    def _get_all_state_from_cache(self, group):
+    def _get_all_state_from_cache(self, cache, group):
         """Checks if group is in cache. See `_get_state_for_groups`
 
         Returns 2-tuple (`state_dict`, `got_all`). `got_all` is a bool
@@ -656,9 +705,10 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         cache, if False we need to query the DB for the missing state.
 
         Args:
+            cache(DictionaryCache): the state group cache to use
             group: The state group to lookup
         """
-        is_all, _, state_dict_ids = self._state_group_cache.get(group)
+        is_all, _, state_dict_ids = cache.get(group)
 
         return state_dict_ids, is_all
 
@@ -681,6 +731,62 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
                 list of event types.  Other types of events are returned unfiltered.
                 If None, `types` filtering is applied to all events.
 
+        Returns:
+            Deferred[dict[int, dict[(type, state_key), EventBase]]]
+                a dictionary mapping from state group to state dictionary.
+        """
+        if types is not None:
+            non_member_types = [t for t in types if t[0] != EventTypes.Member]
+
+            if filtered_types is not None and EventTypes.Member not in filtered_types:
+                # we want all of the membership events
+                member_types = None
+            else:
+                member_types = [t for t in types if t[0] == EventTypes.Member]
+
+        else:
+            non_member_types = None
+            member_types = None
+
+        non_member_state = yield self._get_state_for_groups_using_cache(
+            groups, self._state_group_cache, non_member_types, filtered_types,
+        )
+        # XXX: we could skip this entirely if member_types is []
+        member_state = yield self._get_state_for_groups_using_cache(
+            # we set filtered_types=None as member_state only ever contain members.
+            groups, self._state_group_members_cache, member_types, None,
+        )
+
+        state = non_member_state
+        for group in groups:
+            state[group].update(member_state[group])
+
+        defer.returnValue(state)
+
+    @defer.inlineCallbacks
+    def _get_state_for_groups_using_cache(
+        self, groups, cache, types=None, filtered_types=None
+    ):
+        """Gets the state at each of a list of state groups, optionally
+        filtering by type/state_key, querying from a specific cache.
+
+        Args:
+            groups (iterable[int]): list of state groups for which we want
+                to get the state.
+            cache (DictionaryCache): the cache of group ids to state dicts which
+                we will pass through - either the normal state cache or the specific
+                members state cache.
+            types (None|iterable[(str, None|str)]):
+                indicates the state type/keys required. If None, the whole
+                state is fetched and returned.
+
+                Otherwise, each entry should be a `(type, state_key)` tuple to
+                include in the response. A `state_key` of None is a wildcard
+                meaning that we require all state with that type.
+            filtered_types(list[str]|None): Only apply filtering via `types` to this
+                list of event types.  Other types of events are returned unfiltered.
+                If None, `types` filtering is applied to all events.
+
         Returns:
             Deferred[dict[int, dict[(type, state_key), EventBase]]]
                 a dictionary mapping from state group to state dictionary.
@@ -692,7 +798,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         if types is not None:
             for group in set(groups):
                 state_dict_ids, got_all = self._get_some_state_from_cache(
-                    group, types, filtered_types
+                    cache, group, types, filtered_types
                 )
                 results[group] = state_dict_ids
 
@@ -701,7 +807,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         else:
             for group in set(groups):
                 state_dict_ids, got_all = self._get_all_state_from_cache(
-                    group
+                    cache, group
                 )
 
                 results[group] = state_dict_ids
@@ -710,8 +816,8 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
                     missing_groups.append(group)
 
         if missing_groups:
-            # Okay, so we have some missing_types, lets fetch them.
-            cache_seq_num = self._state_group_cache.sequence
+            # Okay, so we have some missing_types, let's fetch them.
+            cache_seq_num = cache.sequence
 
             # the DictionaryCache knows if it has *all* the state, but
             # does not know if it has all of the keys of a particular type,
@@ -725,7 +831,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
                 types_to_fetch = types
 
             group_to_state_dict = yield self._get_state_groups_from_groups(
-                missing_groups, types_to_fetch
+                missing_groups, types_to_fetch, cache == self._state_group_members_cache,
             )
 
             for group, group_state_dict in iteritems(group_to_state_dict):
@@ -745,7 +851,7 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
 
                 # update the cache with all the things we fetched from the
                 # database.
-                self._state_group_cache.update(
+                cache.update(
                     cache_seq_num,
                     key=group,
                     value=group_state_dict,
@@ -847,15 +953,33 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
                     ],
                 )
 
-            # Prefill the state group cache with this group.
+            # Prefill the state group caches with this group.
             # It's fine to use the sequence like this as the state group map
             # is immutable. (If the map wasn't immutable then this prefill could
             # race with another update)
+
+            current_member_state_ids = {
+                s: ev
+                for (s, ev) in iteritems(current_state_ids)
+                if s[0] == EventTypes.Member
+            }
+            txn.call_after(
+                self._state_group_members_cache.update,
+                self._state_group_members_cache.sequence,
+                key=state_group,
+                value=dict(current_member_state_ids),
+            )
+
+            current_non_member_state_ids = {
+                s: ev
+                for (s, ev) in iteritems(current_state_ids)
+                if s[0] != EventTypes.Member
+            }
             txn.call_after(
                 self._state_group_cache.update,
                 self._state_group_cache.sequence,
                 key=state_group,
-                value=dict(current_state_ids),
+                value=dict(current_non_member_state_ids),
             )
 
             return state_group
diff --git a/tests/handlers/test_profile.py b/tests/handlers/test_profile.py
index 62dc69003c..80da1c8954 100644
--- a/tests/handlers/test_profile.py
+++ b/tests/handlers/test_profile.py
@@ -20,7 +20,7 @@ from twisted.internet import defer
 
 import synapse.types
 from synapse.api.errors import AuthError
-from synapse.handlers.profile import ProfileHandler
+from synapse.handlers.profile import MasterProfileHandler
 from synapse.types import UserID
 
 from tests import unittest
@@ -29,7 +29,7 @@ from tests.utils import setup_test_homeserver
 
 class ProfileHandlers(object):
     def __init__(self, hs):
-        self.profile_handler = ProfileHandler(hs)
+        self.profile_handler = MasterProfileHandler(hs)
 
 
 class ProfileTestCase(unittest.TestCase):
diff --git a/tests/replication/slave/storage/test_events.py b/tests/replication/slave/storage/test_events.py
index 622be2eef8..2ba80ccdcf 100644
--- a/tests/replication/slave/storage/test_events.py
+++ b/tests/replication/slave/storage/test_events.py
@@ -112,6 +112,7 @@ class SlavedEventStoreTestCase(BaseSlavedStoreTestCase):
 
     @defer.inlineCallbacks
     def test_invites(self):
+        yield self.persist(type="m.room.create", key="", creator=USER_ID)
         yield self.check("get_invited_rooms_for_user", [USER_ID_2], [])
         event = yield self.persist(
             type="m.room.member", key=USER_ID_2, membership="invite"
@@ -133,7 +134,7 @@ class SlavedEventStoreTestCase(BaseSlavedStoreTestCase):
 
     @defer.inlineCallbacks
     def test_push_actions_for_user(self):
-        yield self.persist(type="m.room.create", creator=USER_ID)
+        yield self.persist(type="m.room.create", key="", creator=USER_ID)
         yield self.persist(type="m.room.join", key=USER_ID, membership="join")
         yield self.persist(
             type="m.room.join", sender=USER_ID, key=USER_ID_2, membership="join"
diff --git a/tests/storage/test_redaction.py b/tests/storage/test_redaction.py
index c4e9fb72bf..02bf975fbf 100644
--- a/tests/storage/test_redaction.py
+++ b/tests/storage/test_redaction.py
@@ -22,7 +22,7 @@ from synapse.api.constants import EventTypes, Membership
 from synapse.types import RoomID, UserID
 
 from tests import unittest
-from tests.utils import setup_test_homeserver
+from tests.utils import create_room, setup_test_homeserver
 
 
 class RedactionTestCase(unittest.TestCase):
@@ -41,6 +41,8 @@ class RedactionTestCase(unittest.TestCase):
 
         self.room1 = RoomID.from_string("!abc123:test")
 
+        yield create_room(hs, self.room1.to_string(), self.u_alice.to_string())
+
         self.depth = 1
 
     @defer.inlineCallbacks
diff --git a/tests/storage/test_roommember.py b/tests/storage/test_roommember.py
index c83ef60062..978c66133d 100644
--- a/tests/storage/test_roommember.py
+++ b/tests/storage/test_roommember.py
@@ -22,7 +22,7 @@ from synapse.api.constants import EventTypes, Membership
 from synapse.types import RoomID, UserID
 
 from tests import unittest
-from tests.utils import setup_test_homeserver
+from tests.utils import create_room, setup_test_homeserver
 
 
 class RoomMemberStoreTestCase(unittest.TestCase):
@@ -45,6 +45,8 @@ class RoomMemberStoreTestCase(unittest.TestCase):
 
         self.room = RoomID.from_string("!abc123:test")
 
+        yield create_room(hs, self.room.to_string(), self.u_alice.to_string())
+
     @defer.inlineCallbacks
     def inject_room_member(self, room, user, membership, replaces_state=None):
         builder = self.event_builder_factory.new(
diff --git a/tests/storage/test_state.py b/tests/storage/test_state.py
index ebfd969b36..d717b9f94e 100644
--- a/tests/storage/test_state.py
+++ b/tests/storage/test_state.py
@@ -185,6 +185,7 @@ class StateStoreTestCase(tests.unittest.TestCase):
 
         # test _get_some_state_from_cache correctly filters out members with types=[]
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_cache,
             group, [], filtered_types=[EventTypes.Member]
         )
 
@@ -197,8 +198,20 @@ class StateStoreTestCase(tests.unittest.TestCase):
             state_dict,
         )
 
+        (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
+            group, [], filtered_types=[EventTypes.Member]
+        )
+
+        self.assertEqual(is_all, True)
+        self.assertDictEqual(
+            {},
+            state_dict,
+        )
+
         # test _get_some_state_from_cache correctly filters in members with wildcard types
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_cache,
             group, [(EventTypes.Member, None)], filtered_types=[EventTypes.Member]
         )
 
@@ -207,6 +220,18 @@ class StateStoreTestCase(tests.unittest.TestCase):
             {
                 (e1.type, e1.state_key): e1.event_id,
                 (e2.type, e2.state_key): e2.event_id,
+            },
+            state_dict,
+        )
+
+        (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
+            group, [(EventTypes.Member, None)], filtered_types=[EventTypes.Member]
+        )
+
+        self.assertEqual(is_all, True)
+        self.assertDictEqual(
+            {
                 (e3.type, e3.state_key): e3.event_id,
                 # e4 is overwritten by e5
                 (e5.type, e5.state_key): e5.event_id,
@@ -216,6 +241,7 @@ class StateStoreTestCase(tests.unittest.TestCase):
 
         # test _get_some_state_from_cache correctly filters in members with specific types
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_cache,
             group,
             [(EventTypes.Member, e5.state_key)],
             filtered_types=[EventTypes.Member],
@@ -226,6 +252,20 @@ class StateStoreTestCase(tests.unittest.TestCase):
             {
                 (e1.type, e1.state_key): e1.event_id,
                 (e2.type, e2.state_key): e2.event_id,
+            },
+            state_dict,
+        )
+
+        (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
+            group,
+            [(EventTypes.Member, e5.state_key)],
+            filtered_types=[EventTypes.Member],
+        )
+
+        self.assertEqual(is_all, True)
+        self.assertDictEqual(
+            {
                 (e5.type, e5.state_key): e5.event_id,
             },
             state_dict,
@@ -234,6 +274,7 @@ class StateStoreTestCase(tests.unittest.TestCase):
         # test _get_some_state_from_cache correctly filters in members with specific types
         # and no filtered_types
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
             group, [(EventTypes.Member, e5.state_key)], filtered_types=None
         )
 
@@ -254,9 +295,6 @@ class StateStoreTestCase(tests.unittest.TestCase):
             {
                 (e1.type, e1.state_key): e1.event_id,
                 (e2.type, e2.state_key): e2.event_id,
-                (e3.type, e3.state_key): e3.event_id,
-                # e4 is overwritten by e5
-                (e5.type, e5.state_key): e5.event_id,
             },
         )
 
@@ -269,8 +307,6 @@ class StateStoreTestCase(tests.unittest.TestCase):
             # list fetched keys so it knows it's partial
             fetched_keys=(
                 (e1.type, e1.state_key),
-                (e3.type, e3.state_key),
-                (e5.type, e5.state_key),
             ),
         )
 
@@ -284,8 +320,6 @@ class StateStoreTestCase(tests.unittest.TestCase):
             set(
                 [
                     (e1.type, e1.state_key),
-                    (e3.type, e3.state_key),
-                    (e5.type, e5.state_key),
                 ]
             ),
         )
@@ -293,8 +327,6 @@ class StateStoreTestCase(tests.unittest.TestCase):
             state_dict_ids,
             {
                 (e1.type, e1.state_key): e1.event_id,
-                (e3.type, e3.state_key): e3.event_id,
-                (e5.type, e5.state_key): e5.event_id,
             },
         )
 
@@ -304,14 +336,25 @@ class StateStoreTestCase(tests.unittest.TestCase):
         # test _get_some_state_from_cache correctly filters out members with types=[]
         room_id = self.room.to_string()
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_cache,
             group, [], filtered_types=[EventTypes.Member]
         )
 
         self.assertEqual(is_all, False)
         self.assertDictEqual({(e1.type, e1.state_key): e1.event_id}, state_dict)
 
+        room_id = self.room.to_string()
+        (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
+            group, [], filtered_types=[EventTypes.Member]
+        )
+
+        self.assertEqual(is_all, True)
+        self.assertDictEqual({}, state_dict)
+
         # test _get_some_state_from_cache correctly filters in members wildcard types
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_cache,
             group, [(EventTypes.Member, None)], filtered_types=[EventTypes.Member]
         )
 
@@ -319,8 +362,19 @@ class StateStoreTestCase(tests.unittest.TestCase):
         self.assertDictEqual(
             {
                 (e1.type, e1.state_key): e1.event_id,
+            },
+            state_dict,
+        )
+
+        (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
+            group, [(EventTypes.Member, None)], filtered_types=[EventTypes.Member]
+        )
+
+        self.assertEqual(is_all, True)
+        self.assertDictEqual(
+            {
                 (e3.type, e3.state_key): e3.event_id,
-                # e4 is overwritten by e5
                 (e5.type, e5.state_key): e5.event_id,
             },
             state_dict,
@@ -328,6 +382,7 @@ class StateStoreTestCase(tests.unittest.TestCase):
 
         # test _get_some_state_from_cache correctly filters in members with specific types
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_cache,
             group,
             [(EventTypes.Member, e5.state_key)],
             filtered_types=[EventTypes.Member],
@@ -337,6 +392,20 @@ class StateStoreTestCase(tests.unittest.TestCase):
         self.assertDictEqual(
             {
                 (e1.type, e1.state_key): e1.event_id,
+            },
+            state_dict,
+        )
+
+        (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
+            group,
+            [(EventTypes.Member, e5.state_key)],
+            filtered_types=[EventTypes.Member],
+        )
+
+        self.assertEqual(is_all, True)
+        self.assertDictEqual(
+            {
                 (e5.type, e5.state_key): e5.event_id,
             },
             state_dict,
@@ -345,8 +414,22 @@ class StateStoreTestCase(tests.unittest.TestCase):
         # test _get_some_state_from_cache correctly filters in members with specific types
         # and no filtered_types
         (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_cache,
+            group, [(EventTypes.Member, e5.state_key)], filtered_types=None
+        )
+
+        self.assertEqual(is_all, False)
+        self.assertDictEqual({}, state_dict)
+
+        (state_dict, is_all) = yield self.store._get_some_state_from_cache(
+            self.store._state_group_members_cache,
             group, [(EventTypes.Member, e5.state_key)], filtered_types=None
         )
 
         self.assertEqual(is_all, True)
-        self.assertDictEqual({(e5.type, e5.state_key): e5.event_id}, state_dict)
+        self.assertDictEqual(
+            {
+                (e5.type, e5.state_key): e5.event_id,
+            },
+            state_dict,
+        )
diff --git a/tests/test_state.py b/tests/test_state.py
index 96fdb8636c..452a123c3a 100644
--- a/tests/test_state.py
+++ b/tests/test_state.py
@@ -18,7 +18,7 @@ from mock import Mock
 from twisted.internet import defer
 
 from synapse.api.auth import Auth
-from synapse.api.constants import EventTypes, Membership
+from synapse.api.constants import EventTypes, Membership, RoomVersions
 from synapse.events import FrozenEvent
 from synapse.state import StateHandler, StateResolutionHandler
 
@@ -117,6 +117,9 @@ class StateGroupStore(object):
     def register_event_id_state_group(self, event_id, state_group):
         self._event_to_state_group[event_id] = state_group
 
+    def get_room_version(self, room_id):
+        return RoomVersions.V1
+
 
 class DictObj(dict):
     def __init__(self, **kwargs):
@@ -176,7 +179,9 @@ class StateTestCase(unittest.TestCase):
     def test_branch_no_conflict(self):
         graph = Graph(
             nodes={
-                "START": DictObj(type=EventTypes.Create, state_key="", depth=1),
+                "START": DictObj(
+                    type=EventTypes.Create, state_key="", content={}, depth=1,
+                ),
                 "A": DictObj(type=EventTypes.Message, depth=2),
                 "B": DictObj(type=EventTypes.Message, depth=3),
                 "C": DictObj(type=EventTypes.Name, state_key="", depth=3),
diff --git a/tests/test_visibility.py b/tests/test_visibility.py
index 45a78338d6..8d8ce0cab9 100644
--- a/tests/test_visibility.py
+++ b/tests/test_visibility.py
@@ -21,7 +21,7 @@ from synapse.events import FrozenEvent
 from synapse.visibility import filter_events_for_server
 
 import tests.unittest
-from tests.utils import setup_test_homeserver
+from tests.utils import create_room, setup_test_homeserver
 
 logger = logging.getLogger(__name__)
 
@@ -36,6 +36,8 @@ class FilterEventsForServerTestCase(tests.unittest.TestCase):
         self.event_builder_factory = self.hs.get_event_builder_factory()
         self.store = self.hs.get_datastore()
 
+        yield create_room(self.hs, TEST_ROOM_ID, "@someone:ROOM")
+
     @defer.inlineCallbacks
     def test_filtering(self):
         #
diff --git a/tests/utils.py b/tests/utils.py
index bb0fc74054..9f7ff94575 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -24,6 +24,7 @@ from six.moves.urllib import parse as urlparse
 
 from twisted.internet import defer, reactor
 
+from synapse.api.constants import EventTypes
 from synapse.api.errors import CodeMessageException, cs_error
 from synapse.federation.transport import server
 from synapse.http.server import HttpServer
@@ -539,3 +540,32 @@ class DeferredMockCallable(object):
                 "Expected not to received any calls, got:\n"
                 + "\n".join(["call(%s)" % _format_call(c[0], c[1]) for c in calls])
             )
+
+
+@defer.inlineCallbacks
+def create_room(hs, room_id, creator_id):
+    """Creates and persist a creation event for the given room
+
+    Args:
+        hs
+        room_id (str)
+        creator_id (str)
+    """
+
+    store = hs.get_datastore()
+    event_builder_factory = hs.get_event_builder_factory()
+    event_creation_handler = hs.get_event_creation_handler()
+
+    builder = event_builder_factory.new({
+        "type": EventTypes.Create,
+        "state_key": "",
+        "sender": creator_id,
+        "room_id": room_id,
+        "content": {},
+    })
+
+    event, context = yield event_creation_handler.create_new_client_event(
+        builder
+    )
+
+    yield store.persist_event(event, context)