diff --git a/changelog.d/13045.feature b/changelog.d/13045.feature new file mode 100644 index 0000000000..7b0667ba95 --- /dev/null +++ b/changelog.d/13045.feature @@ -0,0 +1 @@ +Speed up fetching of device list changes in `/sync` and `/keys/changes`. diff --git a/synapse/handlers/device.py b/synapse/handlers/device.py index b79c551703..c05a170c55 100644 --- a/synapse/handlers/device.py +++ b/synapse/handlers/device.py @@ -123,6 +123,43 @@ class DeviceWorkerHandler: return device + async def get_device_changes_in_shared_rooms( + self, user_id: str, room_ids: Collection[str], from_token: StreamToken + ) -> Collection[str]: + """Get the set of users whose devices have changed who share a room with + the given user. + """ + changed_users = await self.store.get_device_list_changes_in_rooms( + room_ids, from_token.device_list_key + ) + + if changed_users is not None: + # We also check if the given user has changed their device. If + # they're in no rooms then the above query won't include them. + changed = await self.store.get_users_whose_devices_changed( + from_token.device_list_key, [user_id] + ) + changed_users.update(changed) + return changed_users + + # If the DB returned None then the `from_token` is too old, so we fall + # back on looking for device updates for all users. + + users_who_share_room = await self.store.get_users_who_share_room_with_user( + user_id + ) + + tracked_users = set(users_who_share_room) + + # Always tell the user about their own devices + tracked_users.add(user_id) + + changed = await self.store.get_users_whose_devices_changed( + from_token.device_list_key, tracked_users + ) + + return changed + @trace @measure_func("device.get_user_ids_changed") async def get_user_ids_changed( @@ -138,19 +175,8 @@ class DeviceWorkerHandler: room_ids = await self.store.get_rooms_for_user(user_id) - # First we check if any devices have changed for users that we share - # rooms with. - users_who_share_room = await self.store.get_users_who_share_room_with_user( - user_id - ) - - tracked_users = set(users_who_share_room) - - # Always tell the user about their own devices - tracked_users.add(user_id) - - changed = await self.store.get_users_whose_devices_changed( - from_token.device_list_key, tracked_users + changed = await self.get_device_changes_in_shared_rooms( + user_id, room_ids, from_token ) # Then work out if any users have since joined @@ -237,10 +263,19 @@ class DeviceWorkerHandler: break if possibly_changed or possibly_left: - # Take the intersection of the users whose devices may have changed - # and those that actually still share a room with the user - possibly_joined = possibly_changed & users_who_share_room - possibly_left = (possibly_changed | possibly_left) - users_who_share_room + possibly_joined = possibly_changed + possibly_left = possibly_changed | possibly_left + + # Double check if we still share rooms with the given user. + users_rooms = await self.store.get_rooms_for_users_with_stream_ordering( + possibly_left + ) + for changed_user_id, entries in users_rooms.items(): + if any(e.room_id in room_ids for e in entries): + possibly_left.discard(changed_user_id) + else: + possibly_joined.discard(changed_user_id) + else: possibly_joined = set() possibly_left = set() diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py index 6ad053f678..d42a414c90 100644 --- a/synapse/handlers/sync.py +++ b/synapse/handlers/sync.py @@ -240,6 +240,7 @@ class SyncHandler: self.auth_blocking = hs.get_auth_blocking() self._storage_controllers = hs.get_storage_controllers() self._state_storage_controller = self._storage_controllers.state + self._device_handler = hs.get_device_handler() # TODO: flush cache entries on subsequent sync request. # Once we get the next /sync request (ie, one with the same access token @@ -1268,21 +1269,11 @@ class SyncHandler: ): users_that_have_changed.add(changed_user_id) else: - users_who_share_room = ( - await self.store.get_users_who_share_room_with_user(user_id) - ) - - # Always tell the user about their own devices. We check as the user - # ID is almost certainly already included (unless they're not in any - # rooms) and taking a copy of the set is relatively expensive. - if user_id not in users_who_share_room: - users_who_share_room = set(users_who_share_room) - users_who_share_room.add(user_id) - - tracked_users = users_who_share_room users_that_have_changed = ( - await self.store.get_users_whose_devices_changed( - since_token.device_list_key, tracked_users + await self._device_handler.get_device_changes_in_shared_rooms( + user_id, + sync_result_builder.joined_room_ids, + from_token=since_token, ) ) diff --git a/synapse/storage/databases/main/devices.py b/synapse/storage/databases/main/devices.py index 03d1334e03..93d980786e 100644 --- a/synapse/storage/databases/main/devices.py +++ b/synapse/storage/databases/main/devices.py @@ -1208,6 +1208,65 @@ class DeviceWorkerStore(EndToEndKeyWorkerStore): return devices + @cached() + async def _get_min_device_lists_changes_in_room(self) -> int: + """Returns the minimum stream ID that we have entries for + `device_lists_changes_in_room` + """ + + return await self.db_pool.simple_select_one_onecol( + table="device_lists_changes_in_room", + keyvalues={}, + retcol="COALESCE(MIN(stream_id), 0)", + desc="get_min_device_lists_changes_in_room", + ) + + async def get_device_list_changes_in_rooms( + self, room_ids: Collection[str], from_id: int + ) -> Optional[Set[str]]: + """Return the set of users whose devices have changed in the given rooms + since the given stream ID. + + Returns None if the given stream ID is too old. + """ + + if not room_ids: + return set() + + min_stream_id = await self._get_min_device_lists_changes_in_room() + + if min_stream_id > from_id: + return None + + sql = """ + SELECT DISTINCT user_id FROM device_lists_changes_in_room + WHERE {clause} AND stream_id >= ? + """ + + def _get_device_list_changes_in_rooms_txn( + txn: LoggingTransaction, + clause, + args, + ) -> Set[str]: + txn.execute(sql.format(clause=clause), args) + return {user_id for user_id, in txn} + + changes = set() + for chunk in batch_iter(room_ids, 1000): + clause, args = make_in_list_sql_clause( + self.database_engine, "room_id", chunk + ) + args.append(from_id) + + changes |= await self.db_pool.runInteraction( + "get_device_list_changes_in_rooms", + _get_device_list_changes_in_rooms_txn, + clause, + args, + ) + + return changes + class DeviceBackgroundUpdateStore(SQLBaseStore): def __init__(