diff options
| -rw-r--r-- | changelog.d/16485.bugfix | 1 | ||||
| -rw-r--r-- | synapse/handlers/sync.py | 52 | ||||
| -rw-r--r-- | synapse/storage/databases/main/events.py | 74 | ||||
| -rw-r--r-- | synapse/storage/databases/main/stream.py | 47 | ||||
| -rw-r--r-- | synapse/storage/schema/main/delta/82/05gaps.sql | 25 |
5 files changed, 166 insertions, 33 deletions
diff --git a/changelog.d/16485.bugfix b/changelog.d/16485.bugfix new file mode 100644 index 0000000000..3cd7e1877f --- /dev/null +++ b/changelog.d/16485.bugfix @@ -0,0 +1 @@ +Fix long-standing bug where `/sync` incorrectly did not mark a room as `limited` in a sync requests when there were missing remote events. diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py index 60b4d95cd7..f131c0e8e0 100644 --- a/synapse/handlers/sync.py +++ b/synapse/handlers/sync.py @@ -500,12 +500,27 @@ class SyncHandler: async def _load_filtered_recents( self, room_id: str, + sync_result_builder: "SyncResultBuilder", sync_config: SyncConfig, - now_token: StreamToken, + upto_token: StreamToken, since_token: Optional[StreamToken] = None, potential_recents: Optional[List[EventBase]] = None, newly_joined_room: bool = False, ) -> TimelineBatch: + """Create a timeline batch for the room + + Args: + room_id + sync_result_builder + sync_config + upto_token: The token up to which we should fetch (more) events. + If `potential_results` is non-empty then this is *start* of + the the list. + since_token + potential_recents: If non-empty, the events between the since token + and current token to send down to clients. + newly_joined_room + """ with Measure(self.clock, "load_filtered_recents"): timeline_limit = sync_config.filter_collection.timeline_limit() block_all_timeline = ( @@ -521,6 +536,20 @@ class SyncHandler: else: limited = False + # Check if there is a gap, if so we need to mark this as limited and + # recalculate which events to send down. + gap_token = await self.store.get_timeline_gaps( + room_id, + since_token.room_key if since_token else None, + sync_result_builder.now_token.room_key, + ) + if gap_token: + # There's a gap, so we need to ignore the passed in + # `potential_recents`, and reset `upto_token` to match. + potential_recents = None + upto_token = sync_result_builder.now_token + limited = True + log_kv({"limited": limited}) if potential_recents: @@ -559,10 +588,10 @@ class SyncHandler: recents = [] if not limited or block_all_timeline: - prev_batch_token = now_token + prev_batch_token = upto_token if recents: room_key = recents[0].internal_metadata.before - prev_batch_token = now_token.copy_and_replace( + prev_batch_token = upto_token.copy_and_replace( StreamKeyType.ROOM, room_key ) @@ -573,11 +602,15 @@ class SyncHandler: filtering_factor = 2 load_limit = max(timeline_limit * filtering_factor, 10) max_repeat = 5 # Only try a few times per room, otherwise - room_key = now_token.room_key + room_key = upto_token.room_key end_key = room_key since_key = None - if since_token and not newly_joined_room: + if since_token and gap_token: + # If there is a gap then we need to only include events after + # it. + since_key = gap_token + elif since_token and not newly_joined_room: since_key = since_token.room_key while limited and len(recents) < timeline_limit and max_repeat: @@ -647,7 +680,7 @@ class SyncHandler: recents = recents[-timeline_limit:] room_key = recents[0].internal_metadata.before - prev_batch_token = now_token.copy_and_replace(StreamKeyType.ROOM, room_key) + prev_batch_token = upto_token.copy_and_replace(StreamKeyType.ROOM, room_key) # Don't bother to bundle aggregations if the timeline is unlimited, # as clients will have all the necessary information. @@ -662,7 +695,9 @@ class SyncHandler: return TimelineBatch( events=recents, prev_batch=prev_batch_token, - limited=limited or newly_joined_room, + # Also mark as limited if this is a new room or there has been a gap + # (to force client to paginate the gap). + limited=limited or newly_joined_room or gap_token is not None, bundled_aggregations=bundled_aggregations, ) @@ -2397,8 +2432,9 @@ class SyncHandler: batch = await self._load_filtered_recents( room_id, + sync_result_builder, sync_config, - now_token=upto_token, + upto_token=upto_token, since_token=since_token, potential_recents=events, newly_joined_room=newly_joined, diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py index ef6766b5e0..3c1492e3ad 100644 --- a/synapse/storage/databases/main/events.py +++ b/synapse/storage/databases/main/events.py @@ -2267,35 +2267,59 @@ class PersistEventsStore: Forward extremities are handled when we first start persisting the events. """ - # From the events passed in, add all of the prev events as backwards extremities. - # Ignore any events that are already backwards extrems or outliers. - query = ( - "INSERT INTO event_backward_extremities (event_id, room_id)" - " SELECT ?, ? WHERE NOT EXISTS (" - " SELECT 1 FROM event_backward_extremities" - " WHERE event_id = ? AND room_id = ?" - " )" - # 1. Don't add an event as a extremity again if we already persisted it - # as a non-outlier. - # 2. Don't add an outlier as an extremity if it has no prev_events - " AND NOT EXISTS (" - " SELECT 1 FROM events" - " LEFT JOIN event_edges edge" - " ON edge.event_id = events.event_id" - " WHERE events.event_id = ? AND events.room_id = ? AND (events.outlier = FALSE OR edge.event_id IS NULL)" - " )" + + room_id = events[0].room_id + + potential_backwards_extremities = { + e_id + for ev in events + for e_id in ev.prev_event_ids() + if not ev.internal_metadata.is_outlier() + } + + if not potential_backwards_extremities: + return + + existing_events_outliers = self.db_pool.simple_select_many_txn( + txn, + table="events", + column="event_id", + iterable=potential_backwards_extremities, + keyvalues={"outlier": False}, + retcols=("event_id",), ) - txn.execute_batch( - query, - [ - (e_id, ev.room_id, e_id, ev.room_id, e_id, ev.room_id) - for ev in events - for e_id in ev.prev_event_ids() - if not ev.internal_metadata.is_outlier() - ], + potential_backwards_extremities.difference_update( + e for e, in existing_events_outliers ) + if potential_backwards_extremities: + self.db_pool.simple_upsert_many_txn( + txn, + table="event_backward_extremities", + key_names=("room_id", "event_id"), + key_values=[(room_id, ev) for ev in potential_backwards_extremities], + value_names=(), + value_values=(), + ) + + # Record the stream orderings where we have new gaps. + gap_events = [ + (room_id, self._instance_name, ev.internal_metadata.stream_ordering) + for ev in events + if any( + e_id in potential_backwards_extremities + for e_id in ev.prev_event_ids() + ) + ] + + self.db_pool.simple_insert_many_txn( + txn, + table="timeline_gaps", + keys=("room_id", "instance_name", "stream_ordering"), + values=gap_events, + ) + # Delete all these events that we've already fetched and now know that their # prev events are the new backwards extremeties. query = ( diff --git a/synapse/storage/databases/main/stream.py b/synapse/storage/databases/main/stream.py index ea06e4eee0..872df6bda1 100644 --- a/synapse/storage/databases/main/stream.py +++ b/synapse/storage/databases/main/stream.py @@ -1616,3 +1616,50 @@ class StreamWorkerStore(EventsWorkerStore, SQLBaseStore): retcol="instance_name", desc="get_name_from_instance_id", ) + + async def get_timeline_gaps( + self, + room_id: str, + from_token: Optional[RoomStreamToken], + to_token: RoomStreamToken, + ) -> Optional[RoomStreamToken]: + """Check if there is a gap, and return a token that marks the position + of the gap in the stream. + """ + + sql = """ + SELECT instance_name, stream_ordering + FROM timeline_gaps + WHERE room_id = ? AND ? < stream_ordering AND stream_ordering <= ? + ORDER BY stream_ordering + """ + + rows = await self.db_pool.execute( + "get_timeline_gaps", + None, + sql, + room_id, + from_token.stream if from_token else 0, + to_token.get_max_stream_pos(), + ) + + if not rows: + return None + + positions = [ + PersistedEventPosition(instance_name, stream_ordering) + for instance_name, stream_ordering in rows + ] + if from_token: + positions = [p for p in positions if p.persisted_after(from_token)] + + positions = [p for p in positions if not p.persisted_after(to_token)] + + if positions: + # We return a stream token that ensures the event *at* the position + # of the gap is included (as the gap is *before* the persisted + # event). + last_position = positions[-1] + return RoomStreamToken(stream=last_position.stream - 1) + + return None diff --git a/synapse/storage/schema/main/delta/82/05gaps.sql b/synapse/storage/schema/main/delta/82/05gaps.sql new file mode 100644 index 0000000000..6813b488ca --- /dev/null +++ b/synapse/storage/schema/main/delta/82/05gaps.sql @@ -0,0 +1,25 @@ +/* Copyright 2023 The Matrix.org Foundation C.I.C + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +-- Records when we see a "gap in the timeline", due to missing events over +-- federation. We record this so that we can tell clients there is a gap (by +-- marking the timeline section of a sync request as limited). +CREATE TABLE IF NOT EXISTS timeline_gaps ( + room_id TEXT NOT NULL, + instance_name TEXT NOT NULL, + stream_ordering BIGINT NOT NULL +); + +CREATE INDEX timeline_gaps_room_id ON timeline_gaps(room_id, stream_ordering); |