diff options
| -rw-r--r-- | synapse/storage/events.py | 186 | ||||
| -rw-r--r-- | synapse/storage/schema/delta/54/delete_forward_extremities.sql | 19 |
2 files changed, 205 insertions, 0 deletions
diff --git a/synapse/storage/events.py b/synapse/storage/events.py index 6e9f3d1dc0..a9be143bd5 100644 --- a/synapse/storage/events.py +++ b/synapse/storage/events.py @@ -221,6 +221,7 @@ class EventsStore( ): EVENT_ORIGIN_SERVER_TS_NAME = "event_origin_server_ts" EVENT_FIELDS_SENDER_URL_UPDATE_NAME = "event_fields_sender_url" + EVENT_DELETE_SOFT_FAILED_EXTREMITIES = "delete_soft_failed_extremities" def __init__(self, db_conn, hs): super(EventsStore, self).__init__(db_conn, hs) @@ -252,6 +253,11 @@ class EventsStore( psql_only=True, ) + self.register_background_update_handler( + self.EVENT_DELETE_SOFT_FAILED_EXTREMITIES, + self._cleanup_extremities_bg_update, + ) + self._event_persist_queue = _EventPeristenceQueue() self._state_resolution_handler = hs.get_state_resolution_handler() @@ -2341,6 +2347,186 @@ class EventsStore( get_all_updated_current_state_deltas_txn, ) + @defer.inlineCallbacks + def _cleanup_extremities_bg_update(self, progress, batch_size): + """Background update to clean out extremities that should have been + deleted previously. + + Mainly used to deal with the aftermath of #5269. + """ + + # This works by first copying all existing forward extremities into the + # `_extremities_to_check` table at start up, and then checking each + # event in that table whether we have any descendants that are not + # soft-failed/rejected. If that is the case then we delete that event + # from the forward extremities table. + # + # For efficiency, we do this in batches by recursively pulling out all + # descendants of a batch until we find the non soft-failed/rejected + # events, i.e. the set of descendants whose chain of prev events back + # to the batch of extremities are all soft-failed or rejected. + # Typically, we won't find any such events as extremities will rarely + # have any descendants, but if they do then we should delete those + # extremities. + + def _cleanup_extremities_bg_update_txn(txn): + # The set of extremity event IDs that we're checking this round + original_set = set() + + # A dict[str, set[str]] of event ID to their prev events. + graph = {} + + # The set of descendants of the original set that are not rejected + # nor soft-failed. Ancestors of these events should be removed + # from the forward extremities table. + non_rejected_leaves = set() + + # Set of event IDs that have been soft failed, and for which we + # should check if they have descendants which haven't been soft + # failed. + soft_failed_events_to_lookup = set() + + # First, we get `batch_size` events from the table, pulling out + # their prev events, if any, and their prev events rejection status. + txn.execute( + """SELECT prev_event_id, event_id, internal_metadata, + rejections.event_id IS NOT NULL, events.outlier + FROM ( + SELECT event_id AS prev_event_id + FROM _extremities_to_check + LIMIT ? + ) AS f + LEFT JOIN event_edges USING (prev_event_id) + LEFT JOIN events USING (event_id) + LEFT JOIN event_json USING (event_id) + LEFT JOIN rejections USING (event_id) + """, (batch_size,) + ) + + for prev_event_id, event_id, metadata, rejected, outlier in txn: + original_set.add(prev_event_id) + + if not event_id or outlier: + # Common case where the forward extremity doesn't have any + # descendants. + continue + + graph.setdefault(event_id, set()).add(prev_event_id) + + soft_failed = False + if metadata: + soft_failed = json.loads(metadata).get("soft_failed") + + if soft_failed or rejected: + soft_failed_events_to_lookup.add(event_id) + else: + non_rejected_leaves.add(event_id) + + # Now we recursively check all the soft-failed descendants we + # found above in the same way, until we have nothing left to + # check. + while soft_failed_events_to_lookup: + # We only want to do 100 at a time, so we split given list + # into two. + batch = list(soft_failed_events_to_lookup) + to_check, to_defer = batch[:100], batch[100:] + soft_failed_events_to_lookup = set(to_defer) + + sql = """SELECT prev_event_id, event_id, internal_metadata, + rejections.event_id IS NOT NULL + FROM event_edges + INNER JOIN events USING (event_id) + INNER JOIN event_json USING (event_id) + LEFT JOIN rejections USING (event_id) + WHERE + prev_event_id IN (%s) + AND NOT events.outlier + """ % ( + ",".join("?" for _ in to_check), + ) + txn.execute(sql, to_check) + + for prev_event_id, event_id, metadata, rejected in txn: + if event_id in graph: + # Already handled this event previously, but we still + # want to record the edge. + graph.setdefault(event_id, set()).add(prev_event_id) + logger.info("Already handled") + continue + + graph.setdefault(event_id, set()).add(prev_event_id) + + soft_failed = json.loads(metadata).get("soft_failed") + if soft_failed or rejected: + soft_failed_events_to_lookup.add(event_id) + else: + non_rejected_leaves.add(event_id) + + # We have a set of non-soft-failed descendants, so we recurse up + # the graph to find all ancestors and add them to the set of event + # IDs that we can delete from forward extremities table. + to_delete = set() + while non_rejected_leaves: + event_id = non_rejected_leaves.pop() + prev_event_ids = graph.get(event_id, set()) + non_rejected_leaves.update(prev_event_ids) + to_delete.update(prev_event_ids) + + to_delete.intersection_update(original_set) + + logger.info("Deleting up to %d forward extremities", len(to_delete)) + + self._simple_delete_many_txn( + txn=txn, + table="event_forward_extremities", + column="event_id", + iterable=to_delete, + keyvalues={}, + ) + + if to_delete: + # We now need to invalidate the caches of these rooms + rows = self._simple_select_many_txn( + txn, + table="events", + column="event_id", + iterable=to_delete, + keyvalues={}, + retcols=("room_id",) + ) + for row in rows: + txn.call_after( + self.get_latest_event_ids_in_room.invalidate, + (row["room_id"],) + ) + + self._simple_delete_many_txn( + txn=txn, + table="_extremities_to_check", + column="event_id", + iterable=original_set, + keyvalues={}, + ) + + return len(original_set) + + num_handled = yield self.runInteraction( + "_cleanup_extremities_bg_update", _cleanup_extremities_bg_update_txn, + ) + + if not num_handled: + yield self._end_background_update(self.EVENT_DELETE_SOFT_FAILED_EXTREMITIES) + + def _drop_table_txn(txn): + txn.execute("DROP TABLE _extremities_to_check") + + yield self.runInteraction( + "_cleanup_extremities_bg_update_drop_table", + _drop_table_txn, + ) + + defer.returnValue(num_handled) + AllNewEventsResult = namedtuple( "AllNewEventsResult", diff --git a/synapse/storage/schema/delta/54/delete_forward_extremities.sql b/synapse/storage/schema/delta/54/delete_forward_extremities.sql new file mode 100644 index 0000000000..7056bd1d00 --- /dev/null +++ b/synapse/storage/schema/delta/54/delete_forward_extremities.sql @@ -0,0 +1,19 @@ +/* Copyright 2019 The Matrix.org Foundation C.I.C. + * + * Licensed under the Apache License, Version 2.0 (the "License"); + * you may not use this file except in compliance with the License. + * You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, software + * distributed under the License is distributed on an "AS IS" BASIS, + * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. + * See the License for the specific language governing permissions and + * limitations under the License. + */ + +INSERT INTO background_updates (update_name, progress_json) VALUES + ('delete_soft_failed_extremities', '{}'); + +CREATE TABLE _extremities_to_check AS SELECT event_id FROM event_forward_extremities; |