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authorSteven Hammerton <steven.hammerton@openmarket.com>2015-11-17 10:55:41 +0000
committerSteven Hammerton <steven.hammerton@openmarket.com>2015-11-17 10:55:41 +0000
commitf5e25c5f358de93f8bbba83496a44cf217ce086a (patch)
treec01c8462aa3a004e103de4befc45b7f9206439b1 /synapse
parentSnakes not camels (diff)
parentMerge pull request #376 from matrix-org/daniel/jenkins (diff)
downloadsynapse-f5e25c5f358de93f8bbba83496a44cf217ce086a.tar.xz
Merge branch 'develop' into sh-cas-auth-via-homeserver
Diffstat (limited to 'synapse')
-rw-r--r--synapse/__init__.py2
-rw-r--r--synapse/api/constants.py1
-rwxr-xr-xsynapse/app/homeserver.py1
-rw-r--r--synapse/config/_base.py6
-rw-r--r--synapse/federation/federation_client.py11
-rw-r--r--synapse/handlers/_base.py63
-rw-r--r--synapse/handlers/federation.py21
-rw-r--r--synapse/handlers/message.py87
-rw-r--r--synapse/handlers/presence.py3
-rw-r--r--synapse/handlers/room.py39
-rw-r--r--synapse/handlers/sync.py205
-rw-r--r--synapse/notifier.py20
-rw-r--r--synapse/rest/client/v1/profile.py2
-rw-r--r--synapse/rest/client/v1/room.py42
-rw-r--r--synapse/rest/client/v2_alpha/sync.py123
-rw-r--r--synapse/state.py32
-rw-r--r--synapse/storage/background_updates.py256
-rw-r--r--synapse/storage/events.py8
-rw-r--r--synapse/storage/room.py71
-rw-r--r--synapse/storage/schema/delta/25/00background_updates.sql21
-rw-r--r--synapse/storage/schema/delta/25/fts.py101
-rw-r--r--synapse/storage/schema/delta/25/guest_access.sql25
-rw-r--r--synapse/storage/schema/delta/25/history_visibility.sql1
-rw-r--r--synapse/storage/search.py120
-rw-r--r--synapse/storage/state.py14
-rw-r--r--synapse/storage/tags.py2
-rw-r--r--synapse/storage/transactions.py2
-rw-r--r--synapse/util/__init__.py8
28 files changed, 1003 insertions, 284 deletions
diff --git a/synapse/__init__.py b/synapse/__init__.py
index e9ce0412ed..f68a15bb85 100644
--- a/synapse/__init__.py
+++ b/synapse/__init__.py
@@ -16,4 +16,4 @@
 """ This is a reference implementation of a Matrix home server.
 """
 
-__version__ = "0.10.1-rc1"
+__version__ = "0.11.0-rc1"
diff --git a/synapse/api/constants.py b/synapse/api/constants.py
index 41125e8719..c2450b771a 100644
--- a/synapse/api/constants.py
+++ b/synapse/api/constants.py
@@ -68,6 +68,7 @@ class EventTypes(object):
     RoomHistoryVisibility = "m.room.history_visibility"
     CanonicalAlias = "m.room.canonical_alias"
     RoomAvatar = "m.room.avatar"
+    GuestAccess = "m.room.guest_access"
 
     # These are used for validation
     Message = "m.room.message"
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index a77535a4ee..cd7a52ec07 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -439,6 +439,7 @@ def setup(config_options):
     hs.get_pusherpool().start()
     hs.get_state_handler().start_caching()
     hs.get_datastore().start_profiling()
+    hs.get_datastore().start_doing_background_updates()
     hs.get_replication_layer().start_get_pdu_cache()
 
     return hs
diff --git a/synapse/config/_base.py b/synapse/config/_base.py
index ceef309afc..c18e0bdbb8 100644
--- a/synapse/config/_base.py
+++ b/synapse/config/_base.py
@@ -14,6 +14,7 @@
 # limitations under the License.
 
 import argparse
+import errno
 import os
 import yaml
 import sys
@@ -91,8 +92,11 @@ class Config(object):
     @classmethod
     def ensure_directory(cls, dir_path):
         dir_path = cls.abspath(dir_path)
-        if not os.path.exists(dir_path):
+        try:
             os.makedirs(dir_path)
+        except OSError, e:
+            if e.errno != errno.EEXIST:
+                raise
         if not os.path.isdir(dir_path):
             raise ConfigError(
                 "%s is not a directory" % (dir_path,)
diff --git a/synapse/federation/federation_client.py b/synapse/federation/federation_client.py
index c0c0b693b8..c6a8c1249a 100644
--- a/synapse/federation/federation_client.py
+++ b/synapse/federation/federation_client.py
@@ -357,7 +357,8 @@ class FederationClient(FederationBase):
         defer.returnValue(signed_auth)
 
     @defer.inlineCallbacks
-    def make_membership_event(self, destinations, room_id, user_id, membership):
+    def make_membership_event(self, destinations, room_id, user_id, membership,
+                              content={},):
         """
         Creates an m.room.member event, with context, without participating in the room.
 
@@ -398,6 +399,14 @@ class FederationClient(FederationBase):
 
                 logger.debug("Got response to make_%s: %s", membership, pdu_dict)
 
+                pdu_dict["content"].update(content)
+
+                # The protoevent received over the JSON wire may not have all
+                # the required fields. Lets just gloss over that because
+                # there's some we never care about
+                if "prev_state" not in pdu_dict:
+                    pdu_dict["prev_state"] = []
+
                 defer.returnValue(
                     (destination, self.event_from_pdu_json(pdu_dict))
                 )
diff --git a/synapse/handlers/_base.py b/synapse/handlers/_base.py
index eef325a94b..6519f183df 100644
--- a/synapse/handlers/_base.py
+++ b/synapse/handlers/_base.py
@@ -29,6 +29,12 @@ logger = logging.getLogger(__name__)
 
 
 class BaseHandler(object):
+    """
+    Common base class for the event handlers.
+
+    :type store: synapse.storage.events.StateStore
+    :type state_handler: synapse.state.StateHandler
+    """
 
     def __init__(self, hs):
         self.store = hs.get_datastore()
@@ -175,6 +181,8 @@ class BaseHandler(object):
         if not suppress_auth:
             self.auth.check(event, auth_events=context.current_state)
 
+        yield self.maybe_kick_guest_users(event, context.current_state.values())
+
         if event.type == EventTypes.CanonicalAlias:
             # Check the alias is acually valid (at this time at least)
             room_alias_str = event.content.get("alias", None)
@@ -282,3 +290,58 @@ class BaseHandler(object):
         federation_handler.handle_new_event(
             event, destinations=destinations,
         )
+
+    @defer.inlineCallbacks
+    def maybe_kick_guest_users(self, event, current_state):
+        # Technically this function invalidates current_state by changing it.
+        # Hopefully this isn't that important to the caller.
+        if event.type == EventTypes.GuestAccess:
+            guest_access = event.content.get("guest_access", "forbidden")
+            if guest_access != "can_join":
+                yield self.kick_guest_users(current_state)
+
+    @defer.inlineCallbacks
+    def kick_guest_users(self, current_state):
+        for member_event in current_state:
+            try:
+                if member_event.type != EventTypes.Member:
+                    continue
+
+                if not self.hs.is_mine(UserID.from_string(member_event.state_key)):
+                    continue
+
+                if member_event.content["membership"] not in {
+                    Membership.JOIN,
+                    Membership.INVITE
+                }:
+                    continue
+
+                if (
+                    "kind" not in member_event.content
+                    or member_event.content["kind"] != "guest"
+                ):
+                    continue
+
+                # We make the user choose to leave, rather than have the
+                # event-sender kick them. This is partially because we don't
+                # need to worry about power levels, and partially because guest
+                # users are a concept which doesn't hugely work over federation,
+                # and having homeservers have their own users leave keeps more
+                # of that decision-making and control local to the guest-having
+                # homeserver.
+                message_handler = self.hs.get_handlers().message_handler
+                yield message_handler.create_and_send_event(
+                    {
+                        "type": EventTypes.Member,
+                        "state_key": member_event.state_key,
+                        "content": {
+                            "membership": Membership.LEAVE,
+                            "kind": "guest"
+                        },
+                        "room_id": member_event.room_id,
+                        "sender": member_event.state_key
+                    },
+                    ratelimit=False,
+                )
+            except Exception as e:
+                logger.warn("Error kicking guest user: %s" % (e,))
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
index 872051b8b9..c1bce07e31 100644
--- a/synapse/handlers/federation.py
+++ b/synapse/handlers/federation.py
@@ -564,7 +564,7 @@ class FederationHandler(BaseHandler):
 
     @log_function
     @defer.inlineCallbacks
-    def do_invite_join(self, target_hosts, room_id, joinee):
+    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`.
 
@@ -584,7 +584,8 @@ class FederationHandler(BaseHandler):
             target_hosts,
             room_id,
             joinee,
-            "join"
+            "join",
+            content,
         )
 
         self.room_queues[room_id] = []
@@ -840,12 +841,14 @@ class FederationHandler(BaseHandler):
         defer.returnValue(None)
 
     @defer.inlineCallbacks
-    def _make_and_verify_event(self, target_hosts, room_id, user_id, membership):
+    def _make_and_verify_event(self, target_hosts, room_id, user_id, membership,
+                               content={},):
         origin, pdu = yield self.replication_layer.make_membership_event(
             target_hosts,
             room_id,
             user_id,
-            membership
+            membership,
+            content,
         )
 
         logger.debug("Got response to make_%s: %s", membership, pdu)
@@ -1097,8 +1100,6 @@ class FederationHandler(BaseHandler):
         context = yield self._prep_event(
             origin, event,
             state=state,
-            backfilled=backfilled,
-            current_state=current_state,
             auth_events=auth_events,
         )
 
@@ -1121,7 +1122,6 @@ class FederationHandler(BaseHandler):
                     origin,
                     ev_info["event"],
                     state=ev_info.get("state"),
-                    backfilled=backfilled,
                     auth_events=ev_info.get("auth_events"),
                 )
                 for ev_info in event_infos
@@ -1208,8 +1208,7 @@ class FederationHandler(BaseHandler):
         defer.returnValue((event_stream_id, max_stream_id))
 
     @defer.inlineCallbacks
-    def _prep_event(self, origin, event, state=None, backfilled=False,
-                    current_state=None, auth_events=None):
+    def _prep_event(self, origin, event, state=None, auth_events=None):
         outlier = event.internal_metadata.is_outlier()
 
         context = yield self.state_handler.compute_event_context(
@@ -1242,6 +1241,10 @@ class FederationHandler(BaseHandler):
 
             context.rejected = RejectedReason.AUTH_ERROR
 
+        if event.type == EventTypes.GuestAccess:
+            full_context = yield self.store.get_current_state(room_id=event.room_id)
+            yield self.maybe_kick_guest_users(event, full_context)
+
         defer.returnValue(context)
 
     @defer.inlineCallbacks
diff --git a/synapse/handlers/message.py b/synapse/handlers/message.py
index 654ecd2b37..14051aee99 100644
--- a/synapse/handlers/message.py
+++ b/synapse/handlers/message.py
@@ -167,7 +167,7 @@ class MessageHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def create_and_send_event(self, event_dict, ratelimit=True,
-                              token_id=None, txn_id=None):
+                              token_id=None, txn_id=None, is_guest=False):
         """ Given a dict from a client, create and handle a new event.
 
         Creates an FrozenEvent object, filling out auth_events, prev_events,
@@ -213,7 +213,7 @@ class MessageHandler(BaseHandler):
 
         if event.type == EventTypes.Member:
             member_handler = self.hs.get_handlers().room_member_handler
-            yield member_handler.change_membership(event, context)
+            yield member_handler.change_membership(event, context, is_guest=is_guest)
         else:
             yield self.handle_new_client_event(
                 event=event,
@@ -258,20 +258,30 @@ class MessageHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def _check_in_room_or_world_readable(self, room_id, user_id, is_guest):
-        if is_guest:
+        try:
+            # check_user_was_in_room will return the most recent membership
+            # event for the user if:
+            #  * The user is a non-guest user, and was ever in the room
+            #  * The user is a guest user, and has joined the room
+            # else it will throw.
+            member_event = yield self.auth.check_user_was_in_room(room_id, user_id)
+            defer.returnValue((member_event.membership, member_event.event_id))
+            return
+        except AuthError, auth_error:
             visibility = yield self.state_handler.get_current_state(
                 room_id, EventTypes.RoomHistoryVisibility, ""
             )
-            if visibility.content["history_visibility"] == "world_readable":
+            if (
+                visibility and
+                visibility.content["history_visibility"] == "world_readable"
+            ):
                 defer.returnValue((Membership.JOIN, None))
                 return
-            else:
-                raise AuthError(
-                    403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
-                )
-        else:
-            member_event = yield self.auth.check_user_was_in_room(room_id, user_id)
-            defer.returnValue((member_event.membership, member_event.event_id))
+            if not is_guest:
+                raise auth_error
+            raise AuthError(
+                403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
+            )
 
     @defer.inlineCallbacks
     def get_state_events(self, user_id, room_id, is_guest=False):
@@ -456,7 +466,7 @@ class MessageHandler(BaseHandler):
         defer.returnValue(ret)
 
     @defer.inlineCallbacks
-    def room_initial_sync(self, user_id, room_id, pagin_config=None):
+    def room_initial_sync(self, user_id, room_id, pagin_config=None, is_guest=False):
         """Capture the a snapshot of a room. If user is currently a member of
         the room this will be what is currently in the room. If the user left
         the room this will be what was in the room when they left.
@@ -473,15 +483,19 @@ class MessageHandler(BaseHandler):
             A JSON serialisable dict with the snapshot of the room.
         """
 
-        member_event = yield self.auth.check_user_was_in_room(room_id, user_id)
+        membership, member_event_id = yield self._check_in_room_or_world_readable(
+            room_id,
+            user_id,
+            is_guest
+        )
 
-        if member_event.membership == Membership.JOIN:
+        if membership == Membership.JOIN:
             result = yield self._room_initial_sync_joined(
-                user_id, room_id, pagin_config, member_event
+                user_id, room_id, pagin_config, membership, is_guest
             )
-        elif member_event.membership == Membership.LEAVE:
+        elif membership == Membership.LEAVE:
             result = yield self._room_initial_sync_parted(
-                user_id, room_id, pagin_config, member_event
+                user_id, room_id, pagin_config, membership, member_event_id, is_guest
             )
 
         private_user_data = []
@@ -497,19 +511,19 @@ class MessageHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def _room_initial_sync_parted(self, user_id, room_id, pagin_config,
-                                  member_event):
+                                  membership, member_event_id, is_guest):
         room_state = yield self.store.get_state_for_events(
-            [member_event.event_id], None
+            [member_event_id], None
         )
 
-        room_state = room_state[member_event.event_id]
+        room_state = room_state[member_event_id]
 
         limit = pagin_config.limit if pagin_config else None
         if limit is None:
             limit = 10
 
         stream_token = yield self.store.get_stream_token_for_event(
-            member_event.event_id
+            member_event_id
         )
 
         messages, token = yield self.store.get_recent_events_for_room(
@@ -519,7 +533,7 @@ class MessageHandler(BaseHandler):
         )
 
         messages = yield self._filter_events_for_client(
-            user_id, messages
+            user_id, messages, is_guest=is_guest
         )
 
         start_token = StreamToken(token[0], 0, 0, 0, 0)
@@ -528,7 +542,7 @@ class MessageHandler(BaseHandler):
         time_now = self.clock.time_msec()
 
         defer.returnValue({
-            "membership": member_event.membership,
+            "membership": membership,
             "room_id": room_id,
             "messages": {
                 "chunk": [serialize_event(m, time_now) for m in messages],
@@ -542,7 +556,7 @@ class MessageHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def _room_initial_sync_joined(self, user_id, room_id, pagin_config,
-                                  member_event):
+                                  membership, is_guest):
         current_state = yield self.state.get_current_state(
             room_id=room_id,
         )
@@ -574,12 +588,14 @@ class MessageHandler(BaseHandler):
 
         @defer.inlineCallbacks
         def get_presence():
-            states = yield presence_handler.get_states(
-                target_users=[UserID.from_string(m.user_id) for m in room_members],
-                auth_user=auth_user,
-                as_event=True,
-                check_auth=False,
-            )
+            states = {}
+            if not is_guest:
+                states = yield presence_handler.get_states(
+                    target_users=[UserID.from_string(m.user_id) for m in room_members],
+                    auth_user=auth_user,
+                    as_event=True,
+                    check_auth=False,
+                )
 
             defer.returnValue(states.values())
 
@@ -599,7 +615,7 @@ class MessageHandler(BaseHandler):
         ).addErrback(unwrapFirstError)
 
         messages = yield self._filter_events_for_client(
-            user_id, messages
+            user_id, messages, is_guest=is_guest, require_all_visible_for_guests=False
         )
 
         start_token = now_token.copy_and_replace("room_key", token[0])
@@ -607,8 +623,7 @@ class MessageHandler(BaseHandler):
 
         time_now = self.clock.time_msec()
 
-        defer.returnValue({
-            "membership": member_event.membership,
+        ret = {
             "room_id": room_id,
             "messages": {
                 "chunk": [serialize_event(m, time_now) for m in messages],
@@ -618,4 +633,8 @@ class MessageHandler(BaseHandler):
             "state": state,
             "presence": presence,
             "receipts": receipts,
-        })
+        }
+        if not is_guest:
+            ret["membership"] = membership
+
+        defer.returnValue(ret)
diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py
index 0b780cd528..aca65096fc 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -950,7 +950,8 @@ class PresenceHandler(BaseHandler):
                 )
                 while len(self._remote_offline_serials) > MAX_OFFLINE_SERIALS:
                     self._remote_offline_serials.pop()  # remove the oldest
-                del self._user_cachemap[user]
+                if user in self._user_cachemap:
+                    del self._user_cachemap[user]
             else:
                 # Remove the user from remote_offline_serials now that they're
                 # no longer offline
diff --git a/synapse/handlers/room.py b/synapse/handlers/room.py
index 8cce8d0e99..3f04752581 100644
--- a/synapse/handlers/room.py
+++ b/synapse/handlers/room.py
@@ -369,7 +369,7 @@ class RoomMemberHandler(BaseHandler):
                     remotedomains.add(member.domain)
 
     @defer.inlineCallbacks
-    def change_membership(self, event, context, do_auth=True):
+    def change_membership(self, event, context, do_auth=True, is_guest=False):
         """ Change the membership status of a user in a room.
 
         Args:
@@ -390,6 +390,20 @@ class RoomMemberHandler(BaseHandler):
         # if this HS is not currently in the room, i.e. we have to do the
         # invite/join dance.
         if event.membership == Membership.JOIN:
+            if is_guest:
+                guest_access = context.current_state.get(
+                    (EventTypes.GuestAccess, ""),
+                    None
+                )
+                is_guest_access_allowed = (
+                    guest_access
+                    and guest_access.content
+                    and "guest_access" in guest_access.content
+                    and guest_access.content["guest_access"] == "can_join"
+                )
+                if not is_guest_access_allowed:
+                    raise AuthError(403, "Guest access not allowed")
+
             yield self._do_join(event, context, do_auth=do_auth)
         else:
             if event.membership == Membership.LEAVE:
@@ -490,7 +504,8 @@ class RoomMemberHandler(BaseHandler):
             yield handler.do_invite_join(
                 room_hosts,
                 room_id,
-                event.user_id
+                event.user_id,
+                event.content,
             )
         else:
             logger.debug("Doing normal join")
@@ -582,7 +597,6 @@ class RoomMemberHandler(BaseHandler):
             medium,
             address,
             id_server,
-            display_name,
             token_id,
             txn_id
     ):
@@ -609,7 +623,6 @@ class RoomMemberHandler(BaseHandler):
         else:
             yield self._make_and_store_3pid_invite(
                 id_server,
-                display_name,
                 medium,
                 address,
                 room_id,
@@ -673,7 +686,6 @@ class RoomMemberHandler(BaseHandler):
     def _make_and_store_3pid_invite(
             self,
             id_server,
-            display_name,
             medium,
             address,
             room_id,
@@ -681,7 +693,7 @@ class RoomMemberHandler(BaseHandler):
             token_id,
             txn_id
     ):
-        token, public_key, key_validity_url = (
+        token, public_key, key_validity_url, display_name = (
             yield self._ask_id_server_for_third_party_invite(
                 id_server,
                 medium,
@@ -725,10 +737,11 @@ class RoomMemberHandler(BaseHandler):
         # TODO: Check for success
         token = data["token"]
         public_key = data["public_key"]
+        display_name = data["display_name"]
         key_validity_url = "%s%s/_matrix/identity/api/v1/pubkey/isvalid" % (
             id_server_scheme, id_server,
         )
-        defer.returnValue((token, public_key, key_validity_url))
+        defer.returnValue((token, public_key, key_validity_url, display_name))
 
 
 class RoomListHandler(BaseHandler):
@@ -753,7 +766,7 @@ class RoomListHandler(BaseHandler):
 
 class RoomContextHandler(BaseHandler):
     @defer.inlineCallbacks
-    def get_event_context(self, user, room_id, event_id, limit):
+    def get_event_context(self, user, room_id, event_id, limit, is_guest):
         """Retrieves events, pagination tokens and state around a given event
         in a room.
 
@@ -777,11 +790,17 @@ class RoomContextHandler(BaseHandler):
         )
 
         results["events_before"] = yield self._filter_events_for_client(
-            user.to_string(), results["events_before"]
+            user.to_string(),
+            results["events_before"],
+            is_guest=is_guest,
+            require_all_visible_for_guests=False
         )
 
         results["events_after"] = yield self._filter_events_for_client(
-            user.to_string(), results["events_after"]
+            user.to_string(),
+            results["events_after"],
+            is_guest=is_guest,
+            require_all_visible_for_guests=False
         )
 
         if results["events_after"]:
diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 5294d96466..6dc9d0fb92 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -47,9 +47,9 @@ class TimelineBatch(collections.namedtuple("TimelineBatch", [
 
 
 class JoinedSyncResult(collections.namedtuple("JoinedSyncResult", [
-    "room_id",
-    "timeline",
-    "state",
+    "room_id",           # str
+    "timeline",          # TimelineBatch
+    "state",             # dict[(str, str), FrozenEvent]
     "ephemeral",
     "private_user_data",
 ])):
@@ -68,9 +68,9 @@ class JoinedSyncResult(collections.namedtuple("JoinedSyncResult", [
 
 
 class ArchivedSyncResult(collections.namedtuple("JoinedSyncResult", [
-    "room_id",
-    "timeline",
-    "state",
+    "room_id",            # str
+    "timeline",           # TimelineBatch
+    "state",              # dict[(str, str), FrozenEvent]
     "private_user_data",
 ])):
     __slots__ = []
@@ -87,8 +87,8 @@ class ArchivedSyncResult(collections.namedtuple("JoinedSyncResult", [
 
 
 class InvitedSyncResult(collections.namedtuple("InvitedSyncResult", [
-    "room_id",
-    "invite",
+    "room_id",   # str
+    "invite",    # FrozenEvent: the invite event
 ])):
     __slots__ = []
 
@@ -254,15 +254,12 @@ class SyncHandler(BaseHandler):
             room_id, sync_config, now_token, since_token=timeline_since_token
         )
 
-        current_state = yield self.state_handler.get_current_state(
-            room_id
-        )
-        current_state_events = current_state.values()
+        current_state = yield self.get_state_at(room_id, now_token)
 
         defer.returnValue(JoinedSyncResult(
             room_id=room_id,
             timeline=batch,
-            state=current_state_events,
+            state=current_state,
             ephemeral=ephemeral_by_room.get(room_id, []),
             private_user_data=self.private_user_data_for_room(
                 room_id, tags_by_room
@@ -272,7 +269,7 @@ class SyncHandler(BaseHandler):
     def private_user_data_for_room(self, room_id, tags_by_room):
         private_user_data = []
         tags = tags_by_room.get(room_id)
-        if tags:
+        if tags is not None:
             private_user_data.append({
                 "type": "m.tag",
                 "content": {"tags": tags},
@@ -311,8 +308,13 @@ class SyncHandler(BaseHandler):
         ephemeral_by_room = {}
 
         for event in typing:
-            room_id = event.pop("room_id")
-            ephemeral_by_room.setdefault(room_id, []).append(event)
+            # we want to exclude the room_id from the event, but modifying the
+            # result returned by the event source is poor form (it might cache
+            # the object)
+            room_id = event["room_id"]
+            event_copy = {k: v for (k, v) in event.iteritems()
+                          if k != "room_id"}
+            ephemeral_by_room.setdefault(room_id, []).append(event_copy)
 
         receipt_key = since_token.receipt_key if since_token else "0"
 
@@ -328,8 +330,11 @@ class SyncHandler(BaseHandler):
         now_token = now_token.copy_and_replace("receipt_key", receipt_key)
 
         for event in receipts:
-            room_id = event.pop("room_id")
-            ephemeral_by_room.setdefault(room_id, []).append(event)
+            room_id = event["room_id"]
+            # exclude room id, as above
+            event_copy = {k: v for (k, v) in event.iteritems()
+                          if k != "room_id"}
+            ephemeral_by_room.setdefault(room_id, []).append(event_copy)
 
         defer.returnValue((now_token, ephemeral_by_room))
 
@@ -346,14 +351,12 @@ class SyncHandler(BaseHandler):
             room_id, sync_config, leave_token, since_token=timeline_since_token
         )
 
-        leave_state = yield self.store.get_state_for_events(
-            [leave_event_id], None
-        )
+        leave_state = yield self.store.get_state_for_event(leave_event_id)
 
         defer.returnValue(ArchivedSyncResult(
             room_id=room_id,
             timeline=batch,
-            state=leave_state[leave_event_id].values(),
+            state=leave_state,
             private_user_data=self.private_user_data_for_room(
                 room_id, tags_by_room
             ),
@@ -417,6 +420,9 @@ class SyncHandler(BaseHandler):
         if len(room_events) <= timeline_limit:
             # There is no gap in any of the rooms. Therefore we can just
             # partition the new events by room and return them.
+            logger.debug("Got %i events for incremental sync - not limited",
+                         len(room_events))
+
             invite_events = []
             leave_events = []
             events_by_room_id = {}
@@ -432,7 +438,12 @@ class SyncHandler(BaseHandler):
 
             for room_id in joined_room_ids:
                 recents = events_by_room_id.get(room_id, [])
-                state = [event for event in recents if event.is_state()]
+                logger.debug("Events for room %s: %r", room_id, recents)
+                state = {
+                    (event.type, event.state_key): event
+                    for event in recents if event.is_state()}
+                limited = False
+
                 if recents:
                     prev_batch = now_token.copy_and_replace(
                         "room_key", recents[0].internal_metadata.before
@@ -440,9 +451,13 @@ class SyncHandler(BaseHandler):
                 else:
                     prev_batch = now_token
 
-                state, limited = yield self.check_joined_room(
-                    sync_config, room_id, state
-                )
+                just_joined = yield self.check_joined_room(sync_config, state)
+                if just_joined:
+                    logger.debug("User has just joined %s: needs full state",
+                                 room_id)
+                    state = yield self.get_state_at(room_id, now_token)
+                    # the timeline is inherently limited if we've just joined
+                    limited = True
 
                 room_sync = JoinedSyncResult(
                     room_id=room_id,
@@ -457,10 +472,15 @@ class SyncHandler(BaseHandler):
                         room_id, tags_by_room
                     ),
                 )
+                logger.debug("Result for room %s: %r", room_id, room_sync)
+
                 if room_sync:
                     joined.append(room_sync)
 
         else:
+            logger.debug("Got %i events for incremental sync - hit limit",
+                         len(room_events))
+
             invite_events = yield self.store.get_invites_for_user(
                 sync_config.user.to_string()
             )
@@ -499,6 +519,9 @@ class SyncHandler(BaseHandler):
     @defer.inlineCallbacks
     def load_filtered_recents(self, room_id, sync_config, now_token,
                               since_token=None):
+        """
+        :returns a Deferred TimelineBatch
+        """
         limited = True
         recents = []
         filtering_factor = 2
@@ -550,6 +573,8 @@ class SyncHandler(BaseHandler):
         Returns:
             A Deferred JoinedSyncResult
         """
+        logger.debug("Doing incremental sync for room %s between %s and %s",
+                     room_id, since_token, now_token)
 
         # TODO(mjark): Check for redactions we might have missed.
 
@@ -559,31 +584,26 @@ class SyncHandler(BaseHandler):
 
         logging.debug("Recents %r", batch)
 
-        # TODO(mjark): This seems racy since this isn't being passed a
-        # token to indicate what point in the stream this is
-        current_state = yield self.state_handler.get_current_state(
-            room_id
-        )
-        current_state_events = current_state.values()
+        current_state = yield self.get_state_at(room_id, now_token)
 
-        state_at_previous_sync = yield self.get_state_at_previous_sync(
-            room_id, since_token=since_token
+        state_at_previous_sync = yield self.get_state_at(
+            room_id, stream_position=since_token
         )
 
-        state_events_delta = yield self.compute_state_delta(
+        state = yield self.compute_state_delta(
             since_token=since_token,
             previous_state=state_at_previous_sync,
-            current_state=current_state_events,
+            current_state=current_state,
         )
 
-        state_events_delta, _ = yield self.check_joined_room(
-            sync_config, room_id, state_events_delta
-        )
+        just_joined = yield self.check_joined_room(sync_config, state)
+        if just_joined:
+            state = yield self.get_state_at(room_id, now_token)
 
         room_sync = JoinedSyncResult(
             room_id=room_id,
             timeline=batch,
-            state=state_events_delta,
+            state=state,
             ephemeral=ephemeral_by_room.get(room_id, []),
             private_user_data=self.private_user_data_for_room(
                 room_id, tags_by_room
@@ -615,16 +635,12 @@ class SyncHandler(BaseHandler):
 
         logging.debug("Recents %r", batch)
 
-        # TODO(mjark): This seems racy since this isn't being passed a
-        # token to indicate what point in the stream this is
-        leave_state = yield self.store.get_state_for_events(
-            [leave_event.event_id], None
+        state_events_at_leave = yield self.store.get_state_for_event(
+            leave_event.event_id
         )
 
-        state_events_at_leave = leave_state[leave_event.event_id].values()
-
-        state_at_previous_sync = yield self.get_state_at_previous_sync(
-            leave_event.room_id, since_token=since_token
+        state_at_previous_sync = yield self.get_state_at(
+            leave_event.room_id, stream_position=since_token
         )
 
         state_events_delta = yield self.compute_state_delta(
@@ -647,60 +663,77 @@ class SyncHandler(BaseHandler):
         defer.returnValue(room_sync)
 
     @defer.inlineCallbacks
-    def get_state_at_previous_sync(self, room_id, since_token):
-        """ Get the room state at the previous sync the client made.
-        Returns:
-            A Deferred list of Events.
+    def get_state_after_event(self, event):
+        """
+        Get the room state after the given event
+
+        :param synapse.events.EventBase event: event of interest
+        :return: A Deferred map from ((type, state_key)->Event)
+        """
+        state = yield self.store.get_state_for_event(event.event_id)
+        if event.is_state():
+            state = state.copy()
+            state[(event.type, event.state_key)] = event
+        defer.returnValue(state)
+
+    @defer.inlineCallbacks
+    def get_state_at(self, room_id, stream_position):
+        """ Get the room state at a particular stream position
+        :param str room_id: room for which to get state
+        :param StreamToken stream_position: point at which to get state
+        :returns: A Deferred map from ((type, state_key)->Event)
         """
         last_events, token = yield self.store.get_recent_events_for_room(
-            room_id, end_token=since_token.room_key, limit=1,
+            room_id, end_token=stream_position.room_key, limit=1,
         )
 
         if last_events:
-            last_event = last_events[0]
-            last_context = yield self.state_handler.compute_event_context(
-                last_event
-            )
-            if last_event.is_state():
-                state = [last_event] + last_context.current_state.values()
-            else:
-                state = last_context.current_state.values()
+            last_event = last_events[-1]
+            state = yield self.get_state_after_event(last_event)
+
         else:
-            state = ()
+            # no events in this room - so presumably no state
+            state = {}
         defer.returnValue(state)
 
     def compute_state_delta(self, since_token, previous_state, current_state):
         """ Works out the differnce in state between the current state and the
         state the client got when it last performed a sync.
-        Returns:
-            A list of events.
+
+        :param str since_token: the point we are comparing against
+        :param dict[(str,str), synapse.events.FrozenEvent] previous_state: the
+            state to compare to
+        :param dict[(str,str), synapse.events.FrozenEvent] current_state: the
+            new state
+
+        :returns A new event dictionary
         """
         # TODO(mjark) Check if the state events were received by the server
         # after the previous sync, since we need to include those state
         # updates even if they occured logically before the previous event.
         # TODO(mjark) Check for new redactions in the state events.
-        previous_dict = {event.event_id: event for event in previous_state}
-        state_delta = []
-        for event in current_state:
-            if event.event_id not in previous_dict:
-                state_delta.append(event)
+
+        state_delta = {}
+        for key, event in current_state.iteritems():
+            if (key not in previous_state or
+                    previous_state[key].event_id != event.event_id):
+                state_delta[key] = event
         return state_delta
 
-    @defer.inlineCallbacks
-    def check_joined_room(self, sync_config, room_id, state_delta):
-        joined = False
-        limited = False
-        for event in state_delta:
-            if (
-                event.type == EventTypes.Member
-                and event.state_key == sync_config.user.to_string()
-            ):
-                if event.content["membership"] == Membership.JOIN:
-                    joined = True
-
-        if joined:
-            res = yield self.state_handler.get_current_state(room_id)
-            state_delta = res.values()
-            limited = True
+    def check_joined_room(self, sync_config, state_delta):
+        """
+        Check if the user has just joined the given room (so should
+        be given the full state)
 
-        defer.returnValue((state_delta, limited))
+        :param sync_config:
+        :param dict[(str,str), synapse.events.FrozenEvent] state_delta: the
+           difference in state since the last sync
+
+        :returns A deferred Tuple (state_delta, limited)
+        """
+        join_event = state_delta.get((
+            EventTypes.Member, sync_config.user.to_string()), None)
+        if join_event is not None:
+            if join_event.content["membership"] == Membership.JOIN:
+                return True
+        return False
diff --git a/synapse/notifier.py b/synapse/notifier.py
index 56c4c863b5..e3b42e2331 100644
--- a/synapse/notifier.py
+++ b/synapse/notifier.py
@@ -14,6 +14,8 @@
 # limitations under the License.
 
 from twisted.internet import defer
+from synapse.api.constants import EventTypes
+from synapse.api.errors import AuthError
 
 from synapse.util.logutils import log_function
 from synapse.util.async import run_on_reactor, ObservableDeferred
@@ -346,9 +348,9 @@ class Notifier(object):
 
         room_ids = []
         if is_guest:
-            # TODO(daniel): Deal with non-room events too
-            only_room_events = True
             if guest_room_id:
+                if not self._is_world_readable(guest_room_id):
+                    raise AuthError(403, "Guest access not allowed")
                 room_ids = [guest_room_id]
         else:
             rooms = yield self.store.get_rooms_for_user(user.to_string())
@@ -361,6 +363,7 @@ class Notifier(object):
 
             events = []
             end_token = from_token
+
             for name, source in self.event_sources.sources.items():
                 keyname = "%s_key" % name
                 before_id = getattr(before_token, keyname)
@@ -377,7 +380,7 @@ class Notifier(object):
                     room_ids=room_ids,
                 )
 
-                if is_guest:
+                if name == "room":
                     room_member_handler = self.hs.get_handlers().room_member_handler
                     new_events = yield room_member_handler._filter_events_for_client(
                         user.to_string(),
@@ -403,6 +406,17 @@ class Notifier(object):
 
         defer.returnValue(result)
 
+    @defer.inlineCallbacks
+    def _is_world_readable(self, room_id):
+        state = yield self.hs.get_state_handler().get_current_state(
+            room_id,
+            EventTypes.RoomHistoryVisibility
+        )
+        if state and "history_visibility" in state.content:
+            defer.returnValue(state.content["history_visibility"] == "world_readable")
+        else:
+            defer.returnValue(False)
+
     @log_function
     def remove_expired_streams(self):
         time_now_ms = self.clock.time_msec()
diff --git a/synapse/rest/client/v1/profile.py b/synapse/rest/client/v1/profile.py
index 6b379e4e5f..3218e47025 100644
--- a/synapse/rest/client/v1/profile.py
+++ b/synapse/rest/client/v1/profile.py
@@ -37,7 +37,7 @@ class ProfileDisplaynameRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_PUT(self, request, user_id):
-        auth_user, _, _ = yield self.auth.get_user_by_req(request)
+        auth_user, _, _ = yield self.auth.get_user_by_req(request, allow_guest=True)
         user = UserID.from_string(user_id)
 
         try:
diff --git a/synapse/rest/client/v1/room.py b/synapse/rest/client/v1/room.py
index 6e0d93766b..139dac1cc3 100644
--- a/synapse/rest/client/v1/room.py
+++ b/synapse/rest/client/v1/room.py
@@ -17,7 +17,7 @@
 from twisted.internet import defer
 
 from base import ClientV1RestServlet, client_path_pattern
-from synapse.api.errors import SynapseError, Codes
+from synapse.api.errors import SynapseError, Codes, AuthError
 from synapse.streams.config import PaginationConfig
 from synapse.api.constants import EventTypes, Membership
 from synapse.types import UserID, RoomID, RoomAlias
@@ -175,7 +175,7 @@ class RoomSendEventRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request, room_id, event_type, txn_id=None):
-        user, token_id, _ = yield self.auth.get_user_by_req(request)
+        user, token_id, _ = yield self.auth.get_user_by_req(request, allow_guest=True)
         content = _parse_json(request)
 
         msg_handler = self.handlers.message_handler
@@ -220,7 +220,10 @@ class JoinRoomAliasServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request, room_identifier, txn_id=None):
-        user, token_id, _ = yield self.auth.get_user_by_req(request)
+        user, token_id, is_guest = yield self.auth.get_user_by_req(
+            request,
+            allow_guest=True
+        )
 
         # the identifier could be a room alias or a room id. Try one then the
         # other if it fails to parse, without swallowing other valid
@@ -242,16 +245,20 @@ class JoinRoomAliasServlet(ClientV1RestServlet):
             defer.returnValue((200, ret_dict))
         else:  # room id
             msg_handler = self.handlers.message_handler
+            content = {"membership": Membership.JOIN}
+            if is_guest:
+                content["kind"] = "guest"
             yield msg_handler.create_and_send_event(
                 {
                     "type": EventTypes.Member,
-                    "content": {"membership": Membership.JOIN},
+                    "content": content,
                     "room_id": identifier.to_string(),
                     "sender": user.to_string(),
                     "state_key": user.to_string(),
                 },
                 token_id=token_id,
                 txn_id=txn_id,
+                is_guest=is_guest,
             )
 
             defer.returnValue((200, {"room_id": identifier.to_string()}))
@@ -319,7 +326,7 @@ class RoomMemberListRestServlet(ClientV1RestServlet):
         }))
 
 
-# TODO: Needs unit testing
+# TODO: Needs better unit testing
 class RoomMessageListRestServlet(ClientV1RestServlet):
     PATTERN = client_path_pattern("/rooms/(?P<room_id>[^/]*)/messages$")
 
@@ -365,12 +372,13 @@ class RoomInitialSyncRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id):
-        user, _, _ = yield self.auth.get_user_by_req(request)
+        user, _, is_guest = yield self.auth.get_user_by_req(request, allow_guest=True)
         pagination_config = PaginationConfig.from_request(request)
         content = yield self.handlers.message_handler.room_initial_sync(
             room_id=room_id,
             user_id=user.to_string(),
             pagin_config=pagination_config,
+            is_guest=is_guest,
         )
         defer.returnValue((200, content))
 
@@ -410,12 +418,12 @@ class RoomEventContext(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_GET(self, request, room_id, event_id):
-        user, _ = yield self.auth.get_user_by_req(request)
+        user, _, is_guest = yield self.auth.get_user_by_req(request, allow_guest=True)
 
         limit = int(request.args.get("limit", [10])[0])
 
         results = yield self.handlers.room_context_handler.get_event_context(
-            user, room_id, event_id, limit,
+            user, room_id, event_id, limit, is_guest
         )
 
         time_now = self.clock.time_msec()
@@ -445,7 +453,13 @@ class RoomMembershipRestServlet(ClientV1RestServlet):
 
     @defer.inlineCallbacks
     def on_POST(self, request, room_id, membership_action, txn_id=None):
-        user, token_id, _ = yield self.auth.get_user_by_req(request)
+        user, token_id, is_guest = yield self.auth.get_user_by_req(
+            request,
+            allow_guest=True
+        )
+
+        if is_guest and membership_action not in {Membership.JOIN, Membership.LEAVE}:
+            raise AuthError(403, "Guest access not allowed")
 
         content = _parse_json(request)
 
@@ -459,7 +473,6 @@ class RoomMembershipRestServlet(ClientV1RestServlet):
                 content["medium"],
                 content["address"],
                 content["id_server"],
-                content["display_name"],
                 token_id,
                 txn_id
             )
@@ -479,22 +492,27 @@ class RoomMembershipRestServlet(ClientV1RestServlet):
 
         msg_handler = self.handlers.message_handler
 
+        content = {"membership": unicode(membership_action)}
+        if is_guest:
+            content["kind"] = "guest"
+
         yield msg_handler.create_and_send_event(
             {
                 "type": EventTypes.Member,
-                "content": {"membership": unicode(membership_action)},
+                "content": content,
                 "room_id": room_id,
                 "sender": user.to_string(),
                 "state_key": state_key,
             },
             token_id=token_id,
             txn_id=txn_id,
+            is_guest=is_guest,
         )
 
         defer.returnValue((200, {}))
 
     def _has_3pid_invite_keys(self, content):
-        for key in {"id_server", "medium", "address", "display_name"}:
+        for key in {"id_server", "medium", "address"}:
             if key not in content:
                 return False
         return True
diff --git a/synapse/rest/client/v2_alpha/sync.py b/synapse/rest/client/v2_alpha/sync.py
index d24507effa..efd8281558 100644
--- a/synapse/rest/client/v2_alpha/sync.py
+++ b/synapse/rest/client/v2_alpha/sync.py
@@ -20,6 +20,7 @@ from synapse.http.servlet import (
 )
 from synapse.handlers.sync import SyncConfig
 from synapse.types import StreamToken
+from synapse.events import FrozenEvent
 from synapse.events.utils import (
     serialize_event, format_event_for_client_v2_without_event_id,
 )
@@ -165,6 +166,20 @@ class SyncRestServlet(RestServlet):
         return {"events": filter.filter_presence(formatted)}
 
     def encode_joined(self, rooms, filter, time_now, token_id):
+        """
+        Encode the joined rooms in a sync result
+
+        :param list[synapse.handlers.sync.JoinedSyncResult] rooms: list of sync
+            results for rooms this user is joined to
+        :param FilterCollection filter: filters to apply to the results
+        :param int time_now: current time - used as a baseline for age
+            calculations
+        :param int token_id: ID of the user's auth token - used for namespacing
+            of transaction IDs
+
+        :return: the joined rooms list, in our response format
+        :rtype: dict[str, dict[str, object]]
+        """
         joined = {}
         for room in rooms:
             joined[room.room_id] = self.encode_room(
@@ -174,6 +189,20 @@ class SyncRestServlet(RestServlet):
         return joined
 
     def encode_invited(self, rooms, filter, time_now, token_id):
+        """
+        Encode the invited rooms in a sync result
+
+        :param list[synapse.handlers.sync.InvitedSyncResult] rooms: list of
+             sync results for rooms this user is joined to
+        :param FilterCollection filter: filters to apply to the results
+        :param int time_now: current time - used as a baseline for age
+            calculations
+        :param int token_id: ID of the user's auth token - used for namespacing
+            of transaction IDs
+
+        :return: the invited rooms list, in our response format
+        :rtype: dict[str, dict[str, object]]
+        """
         invited = {}
         for room in rooms:
             invite = serialize_event(
@@ -189,6 +218,20 @@ class SyncRestServlet(RestServlet):
         return invited
 
     def encode_archived(self, rooms, filter, time_now, token_id):
+        """
+        Encode the archived rooms in a sync result
+
+        :param list[synapse.handlers.sync.ArchivedSyncResult] rooms: list of
+             sync results for rooms this user is joined to
+        :param FilterCollection filter: filters to apply to the results
+        :param int time_now: current time - used as a baseline for age
+            calculations
+        :param int token_id: ID of the user's auth token - used for namespacing
+            of transaction IDs
+
+        :return: the invited rooms list, in our response format
+        :rtype: dict[str, dict[str, object]]
+        """
         joined = {}
         for room in rooms:
             joined[room.room_id] = self.encode_room(
@@ -199,8 +242,28 @@ class SyncRestServlet(RestServlet):
 
     @staticmethod
     def encode_room(room, filter, time_now, token_id, joined=True):
+        """
+        :param JoinedSyncResult|ArchivedSyncResult room: sync result for a
+            single room
+        :param FilterCollection filter: filters to apply to the results
+        :param int time_now: current time - used as a baseline for age
+            calculations
+        :param int token_id: ID of the user's auth token - used for namespacing
+            of transaction IDs
+        :param joined: True if the user is joined to this room - will mean
+            we handle ephemeral events
+
+        :return: the room, encoded in our response format
+        :rtype: dict[str, object]
+        """
         event_map = {}
-        state_events = filter.filter_room_state(room.state)
+        state_dict = room.state
+        timeline_events = filter.filter_room_timeline(room.timeline.events)
+
+        state_dict = SyncRestServlet._rollback_state_for_timeline(
+            state_dict, timeline_events)
+
+        state_events = filter.filter_room_state(state_dict.values())
         state_event_ids = []
         for event in state_events:
             # TODO(mjark): Respect formatting requirements in the filter.
@@ -210,7 +273,6 @@ class SyncRestServlet(RestServlet):
             )
             state_event_ids.append(event.event_id)
 
-        timeline_events = filter.filter_room_timeline(room.timeline.events)
         timeline_event_ids = []
         for event in timeline_events:
             # TODO(mjark): Respect formatting requirements in the filter.
@@ -241,6 +303,63 @@ class SyncRestServlet(RestServlet):
 
         return result
 
+    @staticmethod
+    def _rollback_state_for_timeline(state, timeline):
+        """
+        Wind the state dictionary backwards, so that it represents the
+        state at the start of the timeline, rather than at the end.
+
+        :param dict[(str, str), synapse.events.EventBase] state: the
+            state dictionary. Will be updated to the state before the timeline.
+        :param list[synapse.events.EventBase] timeline: the event timeline
+        :return: updated state dictionary
+        """
+        logger.debug("Processing state dict %r; timeline %r", state,
+                     [e.get_dict() for e in timeline])
+
+        result = state.copy()
+
+        for timeline_event in reversed(timeline):
+            if not timeline_event.is_state():
+                continue
+
+            event_key = (timeline_event.type, timeline_event.state_key)
+
+            logger.debug("Considering %s for removal", event_key)
+
+            state_event = result.get(event_key)
+            if (state_event is None or
+                    state_event.event_id != timeline_event.event_id):
+                # the event in the timeline isn't present in the state
+                # dictionary.
+                #
+                # the most likely cause for this is that there was a fork in
+                # the event graph, and the state is no longer valid. Really,
+                # the event shouldn't be in the timeline. We're going to ignore
+                # it for now, however.
+                logger.warn("Found state event %r in timeline which doesn't "
+                            "match state dictionary", timeline_event)
+                continue
+
+            prev_event_id = timeline_event.unsigned.get("replaces_state", None)
+            logger.debug("Replacing %s with %s in state dict",
+                         timeline_event.event_id, prev_event_id)
+
+            if prev_event_id is None:
+                del result[event_key]
+            else:
+                result[event_key] = FrozenEvent({
+                    "type": timeline_event.type,
+                    "state_key": timeline_event.state_key,
+                    "content": timeline_event.unsigned['prev_content'],
+                    "sender": timeline_event.unsigned['prev_sender'],
+                    "event_id": prev_event_id,
+                    "room_id": timeline_event.room_id,
+                })
+            logger.debug("New value: %r", result.get(event_key))
+
+        return result
+
 
 def register_servlets(hs, http_server):
     SyncRestServlet(hs).register(http_server)
diff --git a/synapse/state.py b/synapse/state.py
index bb225c39cf..8ea2cac5d6 100644
--- a/synapse/state.py
+++ b/synapse/state.py
@@ -71,7 +71,7 @@ class StateHandler(object):
 
     @defer.inlineCallbacks
     def get_current_state(self, room_id, event_type=None, state_key=""):
-        """ Returns the current state for the room as a list. This is done by
+        """ Retrieves the current state for the room. This is done by
         calling `get_latest_events_in_room` to get the leading edges of the
         event graph and then resolving any of the state conflicts.
 
@@ -80,6 +80,8 @@ class StateHandler(object):
 
         If `event_type` is specified, then the method returns only the one
         event (or None) with that `event_type` and `state_key`.
+
+        :returns map from (type, state_key) to event
         """
         event_ids = yield self.store.get_latest_event_ids_in_room(room_id)
 
@@ -177,9 +179,10 @@ class StateHandler(object):
         """ Given a list of event_ids this method fetches the state at each
         event, resolves conflicts between them and returns them.
 
-        Return format is a tuple: (`state_group`, `state_events`), where the
-        first is the name of a state group if one and only one is involved,
-        otherwise `None`.
+        :returns a Deferred tuple of (`state_group`, `state`, `prev_state`).
+        `state_group` is the name of a state group if one and only one is
+        involved. `state` is a map from (type, state_key) to event, and
+        `prev_state` is a list of event ids.
         """
         logger.debug("resolve_state_groups event_ids %s", event_ids)
 
@@ -255,6 +258,11 @@ class StateHandler(object):
             return self._resolve_events(state_sets)
 
     def _resolve_events(self, state_sets, event_type=None, state_key=""):
+        """
+        :returns a tuple (new_state, prev_states). new_state is a map
+        from (type, state_key) to event. prev_states is a list of event_ids.
+        :rtype: (dict[(str, str), synapse.events.FrozenEvent], list[str])
+        """
         state = {}
         for st in state_sets:
             for e in st:
@@ -307,19 +315,23 @@ class StateHandler(object):
 
         We resolve conflicts in the following order:
             1. power levels
-            2. memberships
-            3. other events.
+            2. join rules
+            3. memberships
+            4. other events.
         """
         resolved_state = {}
         power_key = (EventTypes.PowerLevels, "")
-        if power_key in conflicted_state.items():
-            power_levels = conflicted_state[power_key]
-            resolved_state[power_key] = self._resolve_auth_events(power_levels)
+        if power_key in conflicted_state:
+            events = conflicted_state[power_key]
+            logger.debug("Resolving conflicted power levels %r", events)
+            resolved_state[power_key] = self._resolve_auth_events(
+                events, auth_events)
 
         auth_events.update(resolved_state)
 
         for key, events in conflicted_state.items():
             if key[0] == EventTypes.JoinRules:
+                logger.debug("Resolving conflicted join rules %r", events)
                 resolved_state[key] = self._resolve_auth_events(
                     events,
                     auth_events
@@ -329,6 +341,7 @@ class StateHandler(object):
 
         for key, events in conflicted_state.items():
             if key[0] == EventTypes.Member:
+                logger.debug("Resolving conflicted member lists %r", events)
                 resolved_state[key] = self._resolve_auth_events(
                     events,
                     auth_events
@@ -338,6 +351,7 @@ class StateHandler(object):
 
         for key, events in conflicted_state.items():
             if key not in resolved_state:
+                logger.debug("Resolving conflicted state %r:%r", key, events)
                 resolved_state[key] = self._resolve_normal_events(
                     events, auth_events
                 )
diff --git a/synapse/storage/background_updates.py b/synapse/storage/background_updates.py
new file mode 100644
index 0000000000..45fccc2e5e
--- /dev/null
+++ b/synapse/storage/background_updates.py
@@ -0,0 +1,256 @@
+# -*- coding: utf-8 -*-
+# Copyright 2014, 2015 OpenMarket 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.
+
+from ._base import SQLBaseStore
+
+from twisted.internet import defer
+
+import ujson as json
+import logging
+
+logger = logging.getLogger(__name__)
+
+
+class BackgroundUpdatePerformance(object):
+    """Tracks the how long a background update is taking to update its items"""
+
+    def __init__(self, name):
+        self.name = name
+        self.total_item_count = 0
+        self.total_duration_ms = 0
+        self.avg_item_count = 0
+        self.avg_duration_ms = 0
+
+    def update(self, item_count, duration_ms):
+        """Update the stats after doing an update"""
+        self.total_item_count += item_count
+        self.total_duration_ms += duration_ms
+
+        # Exponential moving averages for the number of items updated and
+        # the duration.
+        self.avg_item_count += 0.1 * (item_count - self.avg_item_count)
+        self.avg_duration_ms += 0.1 * (duration_ms - self.avg_duration_ms)
+
+    def average_items_per_ms(self):
+        """An estimate of how long it takes to do a single update.
+        Returns:
+            A duration in ms as a float
+        """
+        if self.total_item_count == 0:
+            return None
+        else:
+            # Use the exponential moving average so that we can adapt to
+            # changes in how long the update process takes.
+            return float(self.avg_item_count) / float(self.avg_duration_ms)
+
+    def total_items_per_ms(self):
+        """An estimate of how long it takes to do a single update.
+        Returns:
+            A duration in ms as a float
+        """
+        if self.total_item_count == 0:
+            return None
+        else:
+            return float(self.total_item_count) / float(self.total_duration_ms)
+
+
+class BackgroundUpdateStore(SQLBaseStore):
+    """ Background updates are updates to the database that run in the
+    background. Each update processes a batch of data at once. We attempt to
+    limit the impact of each update by monitoring how long each batch takes to
+    process and autotuning the batch size.
+    """
+
+    MINIMUM_BACKGROUND_BATCH_SIZE = 100
+    DEFAULT_BACKGROUND_BATCH_SIZE = 100
+    BACKGROUND_UPDATE_INTERVAL_MS = 1000
+    BACKGROUND_UPDATE_DURATION_MS = 100
+
+    def __init__(self, hs):
+        super(BackgroundUpdateStore, self).__init__(hs)
+        self._background_update_performance = {}
+        self._background_update_queue = []
+        self._background_update_handlers = {}
+        self._background_update_timer = None
+
+    @defer.inlineCallbacks
+    def start_doing_background_updates(self):
+        while True:
+            if self._background_update_timer is not None:
+                return
+
+            sleep = defer.Deferred()
+            self._background_update_timer = self._clock.call_later(
+                self.BACKGROUND_UPDATE_INTERVAL_MS / 1000., sleep.callback, None
+            )
+            try:
+                yield sleep
+            finally:
+                self._background_update_timer = None
+
+            try:
+                result = yield self.do_background_update(
+                    self.BACKGROUND_UPDATE_DURATION_MS
+                )
+            except:
+                logger.exception("Error doing update")
+
+            if result is None:
+                logger.info(
+                    "No more background updates to do."
+                    " Unscheduling background update task."
+                )
+                return
+
+    @defer.inlineCallbacks
+    def do_background_update(self, desired_duration_ms):
+        """Does some amount of work on a background update
+        Args:
+            desired_duration_ms(float): How long we want to spend
+                updating.
+        Returns:
+            A deferred that completes once some amount of work is done.
+            The deferred will have a value of None if there is currently
+            no more work to do.
+        """
+        if not self._background_update_queue:
+            updates = yield self._simple_select_list(
+                "background_updates",
+                keyvalues=None,
+                retcols=("update_name",),
+            )
+            for update in updates:
+                self._background_update_queue.append(update['update_name'])
+
+        if not self._background_update_queue:
+            defer.returnValue(None)
+
+        update_name = self._background_update_queue.pop(0)
+        self._background_update_queue.append(update_name)
+
+        update_handler = self._background_update_handlers[update_name]
+
+        performance = self._background_update_performance.get(update_name)
+
+        if performance is None:
+            performance = BackgroundUpdatePerformance(update_name)
+            self._background_update_performance[update_name] = performance
+
+        items_per_ms = performance.average_items_per_ms()
+
+        if items_per_ms is not None:
+            batch_size = int(desired_duration_ms * items_per_ms)
+            # Clamp the batch size so that we always make progress
+            batch_size = max(batch_size, self.MINIMUM_BACKGROUND_BATCH_SIZE)
+        else:
+            batch_size = self.DEFAULT_BACKGROUND_BATCH_SIZE
+
+        progress_json = yield self._simple_select_one_onecol(
+            "background_updates",
+            keyvalues={"update_name": update_name},
+            retcol="progress_json"
+        )
+
+        progress = json.loads(progress_json)
+
+        time_start = self._clock.time_msec()
+        items_updated = yield update_handler(progress, batch_size)
+        time_stop = self._clock.time_msec()
+
+        duration_ms = time_stop - time_start
+
+        logger.info(
+            "Updating %r. Updated %r items in %rms."
+            " (total_rate=%r/ms, current_rate=%r/ms, total_updated=%r)",
+            update_name, items_updated, duration_ms,
+            performance.total_items_per_ms(),
+            performance.average_items_per_ms(),
+            performance.total_item_count,
+        )
+
+        performance.update(items_updated, duration_ms)
+
+        defer.returnValue(len(self._background_update_performance))
+
+    def register_background_update_handler(self, update_name, update_handler):
+        """Register a handler for doing a background update.
+
+        The handler should take two arguments:
+
+        * A dict of the current progress
+        * An integer count of the number of items to update in this batch.
+
+        The handler should return a deferred integer count of items updated.
+        The hander is responsible for updating the progress of the update.
+
+        Args:
+            update_name(str): The name of the update that this code handles.
+            update_handler(function): The function that does the update.
+        """
+        self._background_update_handlers[update_name] = update_handler
+
+    def start_background_update(self, update_name, progress):
+        """Starts a background update running.
+
+        Args:
+            update_name: The update to set running.
+            progress: The initial state of the progress of the update.
+
+        Returns:
+            A deferred that completes once the task has been added to the
+            queue.
+        """
+        # Clear the background update queue so that we will pick up the new
+        # task on the next iteration of do_background_update.
+        self._background_update_queue = []
+        progress_json = json.dumps(progress)
+
+        return self._simple_insert(
+            "background_updates",
+            {"update_name": update_name, "progress_json": progress_json}
+        )
+
+    def _end_background_update(self, update_name):
+        """Removes a completed background update task from the queue.
+
+        Args:
+            update_name(str): The name of the completed task to remove
+        Returns:
+            A deferred that completes once the task is removed.
+        """
+        self._background_update_queue = [
+            name for name in self._background_update_queue if name != update_name
+        ]
+        return self._simple_delete_one(
+            "background_updates", keyvalues={"update_name": update_name}
+        )
+
+    def _background_update_progress_txn(self, txn, update_name, progress):
+        """Update the progress of a background update
+
+        Args:
+            txn(cursor): The transaction.
+            update_name(str): The name of the background update task
+            progress(dict): The progress of the update.
+        """
+
+        progress_json = json.dumps(progress)
+
+        self._simple_update_one_txn(
+            txn,
+            "background_updates",
+            keyvalues={"update_name": update_name},
+            updatevalues={"progress_json": progress_json},
+        )
diff --git a/synapse/storage/events.py b/synapse/storage/events.py
index 59c9987202..5d35ca90b9 100644
--- a/synapse/storage/events.py
+++ b/synapse/storage/events.py
@@ -313,6 +313,8 @@ class EventsStore(SQLBaseStore):
                 self._store_redaction(txn, event)
             elif event.type == EventTypes.RoomHistoryVisibility:
                 self._store_history_visibility_txn(txn, event)
+            elif event.type == EventTypes.GuestAccess:
+                self._store_guest_access_txn(txn, event)
 
         self._store_room_members_txn(
             txn,
@@ -829,7 +831,8 @@ class EventsStore(SQLBaseStore):
                 allow_none=True,
             )
             if prev:
-                ev.unsigned["prev_content"] = prev.get_dict()["content"]
+                ev.unsigned["prev_content"] = prev.content
+                ev.unsigned["prev_sender"] = prev.sender
 
         self._get_event_cache.prefill(
             (ev.event_id, check_redacted, get_prev_content), ev
@@ -886,7 +889,8 @@ class EventsStore(SQLBaseStore):
                 get_prev_content=False,
             )
             if prev:
-                ev.unsigned["prev_content"] = prev.get_dict()["content"]
+                ev.unsigned["prev_content"] = prev.content
+                ev.unsigned["prev_sender"] = prev.sender
 
         self._get_event_cache.prefill(
             (ev.event_id, check_redacted, get_prev_content), ev
diff --git a/synapse/storage/room.py b/synapse/storage/room.py
index 1c79626736..4f08df478c 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -99,34 +99,39 @@ class RoomStore(SQLBaseStore):
         """
 
         def f(txn):
-            topic_subquery = (
-                "SELECT topics.event_id as event_id, "
-                "topics.room_id as room_id, topic "
-                "FROM topics "
-                "INNER JOIN current_state_events as c "
-                "ON c.event_id = topics.event_id "
-            )
-
-            name_subquery = (
-                "SELECT room_names.event_id as event_id, "
-                "room_names.room_id as room_id, name "
-                "FROM room_names "
-                "INNER JOIN current_state_events as c "
-                "ON c.event_id = room_names.event_id "
-            )
+            def subquery(table_name, column_name=None):
+                column_name = column_name or table_name
+                return (
+                    "SELECT %(table_name)s.event_id as event_id, "
+                    "%(table_name)s.room_id as room_id, %(column_name)s "
+                    "FROM %(table_name)s "
+                    "INNER JOIN current_state_events as c "
+                    "ON c.event_id = %(table_name)s.event_id " % {
+                        "column_name": column_name,
+                        "table_name": table_name,
+                    }
+                )
 
-            # We use non printing ascii character US (\x1F) as a separator
             sql = (
-                "SELECT r.room_id, max(n.name), max(t.topic)"
+                "SELECT"
+                "    r.room_id,"
+                "    max(n.name),"
+                "    max(t.topic),"
+                "    max(v.history_visibility),"
+                "    max(g.guest_access)"
                 " FROM rooms AS r"
                 " LEFT JOIN (%(topic)s) AS t ON t.room_id = r.room_id"
                 " LEFT JOIN (%(name)s) AS n ON n.room_id = r.room_id"
+                " LEFT JOIN (%(history_visibility)s) AS v ON v.room_id = r.room_id"
+                " LEFT JOIN (%(guest_access)s) AS g ON g.room_id = r.room_id"
                 " WHERE r.is_public = ?"
-                " GROUP BY r.room_id"
-            ) % {
-                "topic": topic_subquery,
-                "name": name_subquery,
-            }
+                " GROUP BY r.room_id" % {
+                    "topic": subquery("topics", "topic"),
+                    "name": subquery("room_names", "name"),
+                    "history_visibility": subquery("history_visibility"),
+                    "guest_access": subquery("guest_access"),
+                }
+            )
 
             txn.execute(sql, (is_public,))
 
@@ -156,10 +161,12 @@ class RoomStore(SQLBaseStore):
                 "room_id": r[0],
                 "name": r[1],
                 "topic": r[2],
-                "aliases": r[3],
+                "world_readable": r[3] == "world_readable",
+                "guest_can_join": r[4] == "can_join",
+                "aliases": r[5],
             }
             for r in rows
-            if r[3]  # We only return rooms that have at least one alias.
+            if r[5]  # We only return rooms that have at least one alias.
         ]
 
         defer.returnValue(ret)
@@ -203,16 +210,22 @@ class RoomStore(SQLBaseStore):
             )
 
     def _store_history_visibility_txn(self, txn, event):
-        if hasattr(event, "content") and "history_visibility" in event.content:
+        self._store_content_index_txn(txn, event, "history_visibility")
+
+    def _store_guest_access_txn(self, txn, event):
+        self._store_content_index_txn(txn, event, "guest_access")
+
+    def _store_content_index_txn(self, txn, event, key):
+        if hasattr(event, "content") and key in event.content:
             sql = (
-                "INSERT INTO history_visibility"
-                " (event_id, room_id, history_visibility)"
-                " VALUES (?, ?, ?)"
+                "INSERT INTO %(key)s"
+                " (event_id, room_id, %(key)s)"
+                " VALUES (?, ?, ?)" % {"key": key}
             )
             txn.execute(sql, (
                 event.event_id,
                 event.room_id,
-                event.content["history_visibility"]
+                event.content[key]
             ))
 
     def _store_event_search_txn(self, txn, event, key, value):
diff --git a/synapse/storage/schema/delta/25/00background_updates.sql b/synapse/storage/schema/delta/25/00background_updates.sql
new file mode 100644
index 0000000000..41a9b59b1b
--- /dev/null
+++ b/synapse/storage/schema/delta/25/00background_updates.sql
@@ -0,0 +1,21 @@
+/* Copyright 2015 OpenMarket 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.
+ */
+
+
+CREATE TABLE IF NOT EXISTS background_updates(
+    update_name TEXT NOT NULL, -- The name of the background update.
+    progress_json TEXT NOT NULL, -- The current progress of the update as JSON.
+    CONSTRAINT background_updates_uniqueness UNIQUE (update_name)
+);
diff --git a/synapse/storage/schema/delta/25/fts.py b/synapse/storage/schema/delta/25/fts.py
index b7cd0ce3b8..5239d69073 100644
--- a/synapse/storage/schema/delta/25/fts.py
+++ b/synapse/storage/schema/delta/25/fts.py
@@ -22,7 +22,7 @@ import ujson
 logger = logging.getLogger(__name__)
 
 
-POSTGRES_SQL = """
+POSTGRES_TABLE = """
 CREATE TABLE IF NOT EXISTS event_search (
     event_id TEXT,
     room_id TEXT,
@@ -31,22 +31,6 @@ CREATE TABLE IF NOT EXISTS event_search (
     vector tsvector
 );
 
-INSERT INTO event_search SELECT
-    event_id, room_id, json::json->>'sender', 'content.body',
-    to_tsvector('english', json::json->'content'->>'body')
-    FROM events NATURAL JOIN event_json WHERE type = 'm.room.message';
-
-INSERT INTO event_search SELECT
-    event_id, room_id, json::json->>'sender', 'content.name',
-    to_tsvector('english', json::json->'content'->>'name')
-    FROM events NATURAL JOIN event_json WHERE type = 'm.room.name';
-
-INSERT INTO event_search SELECT
-    event_id, room_id, json::json->>'sender', 'content.topic',
-    to_tsvector('english', json::json->'content'->>'topic')
-    FROM events NATURAL JOIN event_json WHERE type = 'm.room.topic';
-
-
 CREATE INDEX event_search_fts_idx ON event_search USING gin(vector);
 CREATE INDEX event_search_ev_idx ON event_search(event_id);
 CREATE INDEX event_search_ev_ridx ON event_search(room_id);
@@ -61,67 +45,34 @@ SQLITE_TABLE = (
 
 def run_upgrade(cur, database_engine, *args, **kwargs):
     if isinstance(database_engine, PostgresEngine):
-        run_postgres_upgrade(cur)
-        return
+        for statement in get_statements(POSTGRES_TABLE.splitlines()):
+            cur.execute(statement)
+    elif isinstance(database_engine, Sqlite3Engine):
+        cur.execute(SQLITE_TABLE)
+    else:
+        raise Exception("Unrecognized database engine")
 
-    if isinstance(database_engine, Sqlite3Engine):
-        run_sqlite_upgrade(cur)
-        return
+    cur.execute("SELECT MIN(stream_ordering) FROM events")
+    rows = cur.fetchall()
+    min_stream_id = rows[0][0]
 
+    cur.execute("SELECT MAX(stream_ordering) FROM events")
+    rows = cur.fetchall()
+    max_stream_id = rows[0][0]
 
-def run_postgres_upgrade(cur):
-    for statement in get_statements(POSTGRES_SQL.splitlines()):
-        cur.execute(statement)
+    if min_stream_id is not None and max_stream_id is not None:
+        progress = {
+            "target_min_stream_id_inclusive": min_stream_id,
+            "max_stream_id_exclusive": max_stream_id + 1,
+            "rows_inserted": 0,
+        }
+        progress_json = ujson.dumps(progress)
 
+        sql = (
+            "INSERT into background_updates (update_name, progress_json)"
+            " VALUES (?, ?)"
+        )
 
-def run_sqlite_upgrade(cur):
-        cur.execute(SQLITE_TABLE)
+        sql = database_engine.convert_param_style(sql)
 
-        rowid = -1
-        while True:
-            cur.execute(
-                "SELECT rowid, json FROM event_json"
-                " WHERE rowid > ?"
-                " ORDER BY rowid ASC LIMIT 100",
-                (rowid,)
-            )
-
-            res = cur.fetchall()
-
-            if not res:
-                break
-
-            events = [
-                ujson.loads(js)
-                for _, js in res
-            ]
-
-            rowid = max(rid for rid, _ in res)
-
-            rows = []
-            for ev in events:
-                content = ev.get("content", {})
-                body = content.get("body", None)
-                name = content.get("name", None)
-                topic = content.get("topic", None)
-                sender = ev.get("sender", None)
-                if ev["type"] == "m.room.message" and body:
-                    rows.append((
-                        ev["event_id"], ev["room_id"], sender, "content.body", body
-                    ))
-                if ev["type"] == "m.room.name" and name:
-                    rows.append((
-                        ev["event_id"], ev["room_id"], sender, "content.name", name
-                    ))
-                if ev["type"] == "m.room.topic" and topic:
-                    rows.append((
-                        ev["event_id"], ev["room_id"], sender, "content.topic", topic
-                    ))
-
-            if rows:
-                logger.info(rows)
-                cur.executemany(
-                    "INSERT INTO event_search (event_id, room_id, sender, key, value)"
-                    " VALUES (?,?,?,?,?)",
-                    rows
-                )
+        cur.execute(sql, ("event_search", progress_json))
diff --git a/synapse/storage/schema/delta/25/guest_access.sql b/synapse/storage/schema/delta/25/guest_access.sql
new file mode 100644
index 0000000000..bdb90e7118
--- /dev/null
+++ b/synapse/storage/schema/delta/25/guest_access.sql
@@ -0,0 +1,25 @@
+/* Copyright 2015 OpenMarket 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.
+ */
+
+/*
+ * This is a manual index of guest_access content of state events,
+ * so that we can join on them in SELECT statements.
+ */
+CREATE TABLE IF NOT EXISTS guest_access(
+    event_id TEXT NOT NULL,
+    room_id TEXT NOT NULL,
+    guest_access TEXT NOT NULL,
+    UNIQUE (event_id)
+);
diff --git a/synapse/storage/schema/delta/25/history_visibility.sql b/synapse/storage/schema/delta/25/history_visibility.sql
index 9f387ed69f..532cb05151 100644
--- a/synapse/storage/schema/delta/25/history_visibility.sql
+++ b/synapse/storage/schema/delta/25/history_visibility.sql
@@ -18,7 +18,6 @@
  * so that we can join on them in SELECT statements.
  */
 CREATE TABLE IF NOT EXISTS history_visibility(
-    id INTEGER PRIMARY KEY,
     event_id TEXT NOT NULL,
     room_id TEXT NOT NULL,
     history_visibility TEXT NOT NULL,
diff --git a/synapse/storage/search.py b/synapse/storage/search.py
index 3cea2011fa..380270b009 100644
--- a/synapse/storage/search.py
+++ b/synapse/storage/search.py
@@ -15,7 +15,7 @@
 
 from twisted.internet import defer
 
-from _base import SQLBaseStore
+from .background_updates import BackgroundUpdateStore
 from synapse.api.errors import SynapseError
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
 
@@ -25,7 +25,106 @@ import logging
 logger = logging.getLogger(__name__)
 
 
-class SearchStore(SQLBaseStore):
+class SearchStore(BackgroundUpdateStore):
+
+    EVENT_SEARCH_UPDATE_NAME = "event_search"
+
+    def __init__(self, hs):
+        super(SearchStore, self).__init__(hs)
+        self.register_background_update_handler(
+            self.EVENT_SEARCH_UPDATE_NAME, self._background_reindex_search
+        )
+
+    @defer.inlineCallbacks
+    def _background_reindex_search(self, progress, batch_size):
+        target_min_stream_id = progress["target_min_stream_id_inclusive"]
+        max_stream_id = progress["max_stream_id_exclusive"]
+        rows_inserted = progress.get("rows_inserted", 0)
+
+        INSERT_CLUMP_SIZE = 1000
+        TYPES = ["m.room.name", "m.room.message", "m.room.topic"]
+
+        def reindex_search_txn(txn):
+            sql = (
+                "SELECT stream_ordering, event_id FROM events"
+                " WHERE ? <= stream_ordering AND stream_ordering < ?"
+                " AND (%s)"
+                " ORDER BY stream_ordering DESC"
+                " LIMIT ?"
+            ) % (" OR ".join("type = '%s'" % (t,) for t in TYPES),)
+
+            txn.execute(sql, (target_min_stream_id, max_stream_id, batch_size))
+
+            rows = txn.fetchall()
+            if not rows:
+                return 0
+
+            min_stream_id = rows[-1][0]
+            event_ids = [row[1] for row in rows]
+
+            events = self._get_events_txn(txn, event_ids)
+
+            event_search_rows = []
+            for event in events:
+                try:
+                    event_id = event.event_id
+                    room_id = event.room_id
+                    content = event.content
+                    if event.type == "m.room.message":
+                        key = "content.body"
+                        value = content["body"]
+                    elif event.type == "m.room.topic":
+                        key = "content.topic"
+                        value = content["topic"]
+                    elif event.type == "m.room.name":
+                        key = "content.name"
+                        value = content["name"]
+                except (KeyError, AttributeError):
+                    # If the event is missing a necessary field then
+                    # skip over it.
+                    continue
+
+                event_search_rows.append((event_id, room_id, key, value))
+
+            if isinstance(self.database_engine, PostgresEngine):
+                sql = (
+                    "INSERT INTO event_search (event_id, room_id, key, vector)"
+                    " VALUES (?,?,?,to_tsvector('english', ?))"
+                )
+            elif isinstance(self.database_engine, Sqlite3Engine):
+                sql = (
+                    "INSERT INTO event_search (event_id, room_id, key, value)"
+                    " VALUES (?,?,?,?)"
+                )
+            else:
+                # This should be unreachable.
+                raise Exception("Unrecognized database engine")
+
+            for index in range(0, len(event_search_rows), INSERT_CLUMP_SIZE):
+                clump = event_search_rows[index:index + INSERT_CLUMP_SIZE]
+                txn.executemany(sql, clump)
+
+            progress = {
+                "target_min_stream_id_inclusive": target_min_stream_id,
+                "max_stream_id_exclusive": min_stream_id,
+                "rows_inserted": rows_inserted + len(event_search_rows)
+            }
+
+            self._background_update_progress_txn(
+                txn, self.EVENT_SEARCH_UPDATE_NAME, progress
+            )
+
+            return len(event_search_rows)
+
+        result = yield self.runInteraction(
+            self.EVENT_SEARCH_UPDATE_NAME, reindex_search_txn
+        )
+
+        if not result:
+            yield self._end_background_update(self.EVENT_SEARCH_UPDATE_NAME)
+
+        defer.returnValue(result)
+
     @defer.inlineCallbacks
     def search_msgs(self, room_ids, search_term, keys):
         """Performs a full text search over events with given keys.
@@ -153,12 +252,23 @@ class SearchStore(SQLBaseStore):
                 " WHERE vector @@ query AND room_id = ?"
             )
         elif isinstance(self.database_engine, Sqlite3Engine):
+            # We use CROSS JOIN here to ensure we use the right indexes.
+            # https://sqlite.org/optoverview.html#crossjoin
+            #
+            # We want to use the full text search index on event_search to
+            # extract all possible matches first, then lookup those matches
+            # in the events table to get the topological ordering. We need
+            # to use the indexes in this order because sqlite refuses to
+            # MATCH unless it uses the full text search index
             sql = (
-                "SELECT rank(matchinfo(event_search)) as rank, room_id, event_id"
+                "SELECT rank(matchinfo) as rank, room_id, event_id,"
                 " topological_ordering, stream_ordering"
+                " FROM (SELECT key, event_id, matchinfo(event_search) as matchinfo"
                 " FROM event_search"
-                " NATURAL JOIN events"
-                " WHERE value MATCH ? AND room_id = ?"
+                " WHERE value MATCH ?"
+                " )"
+                " CROSS JOIN events USING (event_id)"
+                " WHERE room_id = ?"
             )
         else:
             # This should be unreachable.
diff --git a/synapse/storage/state.py b/synapse/storage/state.py
index acfb322a53..80e9b63f50 100644
--- a/synapse/storage/state.py
+++ b/synapse/storage/state.py
@@ -237,6 +237,20 @@ class StateStore(SQLBaseStore):
 
         defer.returnValue({event: event_to_state[event] for event in event_ids})
 
+    @defer.inlineCallbacks
+    def get_state_for_event(self, event_id, types=None):
+        """
+        Get the state dict corresponding to a particular event
+
+        :param str event_id: event whose state should be returned
+        :param list[(str, str)]|None types: List of (type, state_key) tuples
+            which are used to filter the state fetched. May be None, which
+            matches any key
+        :return: a deferred dict from (type, state_key) -> state_event
+        """
+        state_map = yield self.get_state_for_events([event_id], types)
+        defer.returnValue(state_map[event_id])
+
     @cached(num_args=2, lru=True, max_entries=10000)
     def _get_state_group_for_event(self, room_id, event_id):
         return self._simple_select_one_onecol(
diff --git a/synapse/storage/tags.py b/synapse/storage/tags.py
index 641ea250f0..bf695b7800 100644
--- a/synapse/storage/tags.py
+++ b/synapse/storage/tags.py
@@ -95,7 +95,7 @@ class TagsStore(SQLBaseStore):
         if room_ids:
             tags_by_room = yield self.get_tags_for_user(user_id)
             for room_id in room_ids:
-                results[room_id] = tags_by_room[room_id]
+                results[room_id] = tags_by_room.get(room_id, {})
 
         defer.returnValue(results)
 
diff --git a/synapse/storage/transactions.py b/synapse/storage/transactions.py
index 4e0d7c9774..ad099775eb 100644
--- a/synapse/storage/transactions.py
+++ b/synapse/storage/transactions.py
@@ -59,7 +59,7 @@ class TransactionStore(SQLBaseStore):
             allow_none=True,
         )
 
-        if result and result.response_code:
+        if result and result["response_code"]:
             return result["response_code"], result["response_json"]
         else:
             return None
diff --git a/synapse/util/__init__.py b/synapse/util/__init__.py
index 1d123ccefc..d69c7cb991 100644
--- a/synapse/util/__init__.py
+++ b/synapse/util/__init__.py
@@ -53,6 +53,14 @@ class Clock(object):
         loop.stop()
 
     def call_later(self, delay, callback, *args, **kwargs):
+        """Call something later
+
+        Args:
+            delay(float): How long to wait in seconds.
+            callback(function): Function to call
+            *args: Postional arguments to pass to function.
+            **kwargs: Key arguments to pass to function.
+        """
         current_context = LoggingContext.current_context()
 
         def wrapped_callback(*args, **kwargs):