# 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. import logging from typing import Dict, List, Optional, Tuple import attr from synapse.api.constants import EventContentFields from synapse.api.room_versions import KNOWN_ROOM_VERSIONS from synapse.events import make_event_from_dict from synapse.storage._base import SQLBaseStore, db_to_json, make_in_list_sql_clause from synapse.storage.database import DatabasePool, make_tuple_comparison_clause from synapse.storage.databases.main.events import PersistEventsStore from synapse.storage.types import Cursor from synapse.types import JsonDict logger = logging.getLogger(__name__) @attr.s(slots=True, frozen=True) class _CalculateChainCover: """Return value for _calculate_chain_cover_txn.""" # The last room_id/depth/stream processed. room_id = attr.ib(type=str) depth = attr.ib(type=int) stream = attr.ib(type=int) # Number of rows processed processed_count = attr.ib(type=int) # Map from room_id to last depth/stream processed for each room that we have # processed all events for (i.e. the rooms we can flip the # `has_auth_chain_index` for) finished_room_map = attr.ib(type=Dict[str, Tuple[int, int]]) class EventsBackgroundUpdatesStore(SQLBaseStore): EVENT_ORIGIN_SERVER_TS_NAME = "event_origin_server_ts" EVENT_FIELDS_SENDER_URL_UPDATE_NAME = "event_fields_sender_url" DELETE_SOFT_FAILED_EXTREMITIES = "delete_soft_failed_extremities" def __init__(self, database: DatabasePool, db_conn, hs): super().__init__(database, db_conn, hs) self.db_pool.updates.register_background_update_handler( self.EVENT_ORIGIN_SERVER_TS_NAME, self._background_reindex_origin_server_ts ) self.db_pool.updates.register_background_update_handler( self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME, self._background_reindex_fields_sender, ) self.db_pool.updates.register_background_index_update( "event_contains_url_index", index_name="event_contains_url_index", table="events", columns=["room_id", "topological_ordering", "stream_ordering"], where_clause="contains_url = true AND outlier = false", ) # an event_id index on event_search is useful for the purge_history # api. Plus it means we get to enforce some integrity with a UNIQUE # clause self.db_pool.updates.register_background_index_update( "event_search_event_id_idx", index_name="event_search_event_id_idx", table="event_search", columns=["event_id"], unique=True, psql_only=True, ) self.db_pool.updates.register_background_update_handler( self.DELETE_SOFT_FAILED_EXTREMITIES, self._cleanup_extremities_bg_update ) self.db_pool.updates.register_background_update_handler( "redactions_received_ts", self._redactions_received_ts ) # This index gets deleted in `event_fix_redactions_bytes` update self.db_pool.updates.register_background_index_update( "event_fix_redactions_bytes_create_index", index_name="redactions_censored_redacts", table="redactions", columns=["redacts"], where_clause="have_censored", ) self.db_pool.updates.register_background_update_handler( "event_fix_redactions_bytes", self._event_fix_redactions_bytes ) self.db_pool.updates.register_background_update_handler( "event_store_labels", self._event_store_labels ) self.db_pool.updates.register_background_index_update( "redactions_have_censored_ts_idx", index_name="redactions_have_censored_ts", table="redactions", columns=["received_ts"], where_clause="NOT have_censored", ) self.db_pool.updates.register_background_index_update( "users_have_local_media", index_name="users_have_local_media", table="local_media_repository", columns=["user_id", "created_ts"], ) self.db_pool.updates.register_background_update_handler( "rejected_events_metadata", self._rejected_events_metadata, ) self.db_pool.updates.register_background_update_handler( "chain_cover", self._chain_cover_index, ) self.db_pool.updates.register_background_update_handler( "purged_chain_cover", self._purged_chain_cover_index, ) async def _background_reindex_fields_sender(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) def reindex_txn(txn): sql = ( "SELECT stream_ordering, event_id, json FROM events" " INNER JOIN event_json USING (event_id)" " WHERE ? <= stream_ordering AND stream_ordering < ?" " ORDER BY stream_ordering DESC" " LIMIT ?" ) 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] update_rows = [] for row in rows: try: event_id = row[1] event_json = db_to_json(row[2]) sender = event_json["sender"] content = event_json["content"] contains_url = "url" in content if contains_url: contains_url &= isinstance(content["url"], str) except (KeyError, AttributeError): # If the event is missing a necessary field then # skip over it. continue update_rows.append((sender, contains_url, event_id)) sql = "UPDATE events SET sender = ?, contains_url = ? WHERE event_id = ?" txn.execute_batch(sql, update_rows) progress = { "target_min_stream_id_inclusive": target_min_stream_id, "max_stream_id_exclusive": min_stream_id, "rows_inserted": rows_inserted + len(rows), } self.db_pool.updates._background_update_progress_txn( txn, self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME, progress ) return len(rows) result = await self.db_pool.runInteraction( self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME, reindex_txn ) if not result: await self.db_pool.updates._end_background_update( self.EVENT_FIELDS_SENDER_URL_UPDATE_NAME ) return result async def _background_reindex_origin_server_ts(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) def reindex_search_txn(txn): sql = ( "SELECT stream_ordering, event_id FROM events" " WHERE ? <= stream_ordering AND stream_ordering < ?" " ORDER BY stream_ordering DESC" " LIMIT ?" ) 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] rows_to_update = [] chunks = [event_ids[i : i + 100] for i in range(0, len(event_ids), 100)] for chunk in chunks: ev_rows = self.db_pool.simple_select_many_txn( txn, table="event_json", column="event_id", iterable=chunk, retcols=["event_id", "json"], keyvalues={}, ) for row in ev_rows: event_id = row["event_id"] event_json = db_to_json(row["json"]) try: origin_server_ts = event_json["origin_server_ts"] except (KeyError, AttributeError): # If the event is missing a necessary field then # skip over it. continue rows_to_update.append((origin_server_ts, event_id)) sql = "UPDATE events SET origin_server_ts = ? WHERE event_id = ?" txn.execute_batch(sql, rows_to_update) progress = { "target_min_stream_id_inclusive": target_min_stream_id, "max_stream_id_exclusive": min_stream_id, "rows_inserted": rows_inserted + len(rows_to_update), } self.db_pool.updates._background_update_progress_txn( txn, self.EVENT_ORIGIN_SERVER_TS_NAME, progress ) return len(rows_to_update) result = await self.db_pool.runInteraction( self.EVENT_ORIGIN_SERVER_TS_NAME, reindex_search_txn ) if not result: await self.db_pool.updates._end_background_update( self.EVENT_ORIGIN_SERVER_TS_NAME ) return result async 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 successor events, if any, and the successor 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 = db_to_json(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 NOT events.outlier AND """ clause, args = make_in_list_sql_clause( self.database_engine, "prev_event_id", to_check ) txn.execute(sql + clause, list(args)) 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[event_id].add(prev_event_id) continue graph[event_id] = {prev_event_id} soft_failed = db_to_json(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) deleted = self.db_pool.simple_delete_many_txn( txn=txn, table="event_forward_extremities", column="event_id", iterable=to_delete, keyvalues={}, ) logger.info( "Deleted %d forward extremities of %d checked, to clean up #5269", deleted, len(original_set), ) if deleted: # We now need to invalidate the caches of these rooms rows = self.db_pool.simple_select_many_txn( txn, table="events", column="event_id", iterable=to_delete, keyvalues={}, retcols=("room_id",), ) room_ids = {row["room_id"] for row in rows} for room_id in room_ids: txn.call_after( self.get_latest_event_ids_in_room.invalidate, (room_id,) ) self.db_pool.simple_delete_many_txn( txn=txn, table="_extremities_to_check", column="event_id", iterable=original_set, keyvalues={}, ) return len(original_set) num_handled = await self.db_pool.runInteraction( "_cleanup_extremities_bg_update", _cleanup_extremities_bg_update_txn ) if not num_handled: await self.db_pool.updates._end_background_update( self.DELETE_SOFT_FAILED_EXTREMITIES ) def _drop_table_txn(txn): txn.execute("DROP TABLE _extremities_to_check") await self.db_pool.runInteraction( "_cleanup_extremities_bg_update_drop_table", _drop_table_txn ) return num_handled async def _redactions_received_ts(self, progress, batch_size): """Handles filling out the `received_ts` column in redactions.""" last_event_id = progress.get("last_event_id", "") def _redactions_received_ts_txn(txn): # Fetch the set of event IDs that we want to update sql = """ SELECT event_id FROM redactions WHERE event_id > ? ORDER BY event_id ASC LIMIT ? """ txn.execute(sql, (last_event_id, batch_size)) rows = txn.fetchall() if not rows: return 0 (upper_event_id,) = rows[-1] # Update the redactions with the received_ts. # # Note: Not all events have an associated received_ts, so we # fallback to using origin_server_ts. If we for some reason don't # have an origin_server_ts, lets just use the current timestamp. # # We don't want to leave it null, as then we'll never try and # censor those redactions. sql = """ UPDATE redactions SET received_ts = ( SELECT COALESCE(received_ts, origin_server_ts, ?) FROM events WHERE events.event_id = redactions.event_id ) WHERE ? <= event_id AND event_id <= ? """ txn.execute(sql, (self._clock.time_msec(), last_event_id, upper_event_id)) self.db_pool.updates._background_update_progress_txn( txn, "redactions_received_ts", {"last_event_id": upper_event_id} ) return len(rows) count = await self.db_pool.runInteraction( "_redactions_received_ts", _redactions_received_ts_txn ) if not count: await self.db_pool.updates._end_background_update("redactions_received_ts") return count async def _event_fix_redactions_bytes(self, progress, batch_size): """Undoes hex encoded censored redacted event JSON.""" def _event_fix_redactions_bytes_txn(txn): # This update is quite fast due to new index. txn.execute( """ UPDATE event_json SET json = convert_from(json::bytea, 'utf8') FROM redactions WHERE redactions.have_censored AND event_json.event_id = redactions.redacts AND json NOT LIKE '{%'; """ ) txn.execute("DROP INDEX redactions_censored_redacts") await self.db_pool.runInteraction( "_event_fix_redactions_bytes", _event_fix_redactions_bytes_txn ) await self.db_pool.updates._end_background_update("event_fix_redactions_bytes") return 1 async def _event_store_labels(self, progress, batch_size): """Background update handler which will store labels for existing events.""" last_event_id = progress.get("last_event_id", "") def _event_store_labels_txn(txn): txn.execute( """ SELECT event_id, json FROM event_json LEFT JOIN event_labels USING (event_id) WHERE event_id > ? AND label IS NULL ORDER BY event_id LIMIT ? """, (last_event_id, batch_size), ) results = list(txn) nbrows = 0 last_row_event_id = "" for (event_id, event_json_raw) in results: try: event_json = db_to_json(event_json_raw) self.db_pool.simple_insert_many_txn( txn=txn, table="event_labels", values=[ { "event_id": event_id, "label": label, "room_id": event_json["room_id"], "topological_ordering": event_json["depth"], } for label in event_json["content"].get( EventContentFields.LABELS, [] ) if isinstance(label, str) ], ) except Exception as e: logger.warning( "Unable to load event %s (no labels will be imported): %s", event_id, e, ) nbrows += 1 last_row_event_id = event_id self.db_pool.updates._background_update_progress_txn( txn, "event_store_labels", {"last_event_id": last_row_event_id} ) return nbrows num_rows = await self.db_pool.runInteraction( desc="event_store_labels", func=_event_store_labels_txn ) if not num_rows: await self.db_pool.updates._end_background_update("event_store_labels") return num_rows async def _rejected_events_metadata(self, progress: dict, batch_size: int) -> int: """Adds rejected events to the `state_events` and `event_auth` metadata tables. """ last_event_id = progress.get("last_event_id", "") def get_rejected_events( txn: Cursor, ) -> List[Tuple[str, str, JsonDict, bool, bool]]: # Fetch rejected event json, their room version and whether we have # inserted them into the state_events or auth_events tables. # # Note we can assume that events that don't have a corresponding # room version are V1 rooms. sql = """ SELECT DISTINCT event_id, COALESCE(room_version, '1'), json, state_events.event_id IS NOT NULL, event_auth.event_id IS NOT NULL FROM rejections INNER JOIN event_json USING (event_id) LEFT JOIN rooms USING (room_id) LEFT JOIN state_events USING (event_id) LEFT JOIN event_auth USING (event_id) WHERE event_id > ? ORDER BY event_id LIMIT ? """ txn.execute( sql, ( last_event_id, batch_size, ), ) return [(row[0], row[1], db_to_json(row[2]), row[3], row[4]) for row in txn] # type: ignore results = await self.db_pool.runInteraction( desc="_rejected_events_metadata_get", func=get_rejected_events ) if not results: await self.db_pool.updates._end_background_update( "rejected_events_metadata" ) return 0 state_events = [] auth_events = [] for event_id, room_version, event_json, has_state, has_event_auth in results: last_event_id = event_id if has_state and has_event_auth: continue room_version_obj = KNOWN_ROOM_VERSIONS.get(room_version) if not room_version_obj: # We no longer support this room version, so we just ignore the # events entirely. logger.info( "Ignoring event with unknown room version %r: %r", room_version, event_id, ) continue event = make_event_from_dict(event_json, room_version_obj) if not event.is_state(): continue if not has_state: state_events.append( { "event_id": event.event_id, "room_id": event.room_id, "type": event.type, "state_key": event.state_key, } ) if not has_event_auth: # Old, dodgy, events may have duplicate auth events, which we # need to deduplicate as we have a unique constraint. for auth_id in set(event.auth_event_ids()): auth_events.append( { "room_id": event.room_id, "event_id": event.event_id, "auth_id": auth_id, } ) if state_events: await self.db_pool.simple_insert_many( table="state_events", values=state_events, desc="_rejected_events_metadata_state_events", ) if auth_events: await self.db_pool.simple_insert_many( table="event_auth", values=auth_events, desc="_rejected_events_metadata_event_auth", ) await self.db_pool.updates._background_update_progress( "rejected_events_metadata", {"last_event_id": last_event_id} ) if len(results) < batch_size: await self.db_pool.updates._end_background_update( "rejected_events_metadata" ) return len(results) async def _chain_cover_index(self, progress: dict, batch_size: int) -> int: """A background updates that iterates over all rooms and generates the chain cover index for them. """ current_room_id = progress.get("current_room_id", "") # Where we've processed up to in the room, defaults to the start of the # room. last_depth = progress.get("last_depth", -1) last_stream = progress.get("last_stream", -1) result = await self.db_pool.runInteraction( "_chain_cover_index", self._calculate_chain_cover_txn, current_room_id, last_depth, last_stream, batch_size, single_room=False, ) finished = result.processed_count == 0 total_rows_processed = result.processed_count current_room_id = result.room_id last_depth = result.depth last_stream = result.stream for room_id, (depth, stream) in result.finished_room_map.items(): # If we've done all the events in the room we flip the # `has_auth_chain_index` in the DB. Note that its possible for # further events to be persisted between the above and setting the # flag without having the chain cover calculated for them. This is # fine as a) the code gracefully handles these cases and b) we'll # calculate them below. await self.db_pool.simple_update( table="rooms", keyvalues={"room_id": room_id}, updatevalues={"has_auth_chain_index": True}, desc="_chain_cover_index", ) # Handle any events that might have raced with us flipping the # bit above. result = await self.db_pool.runInteraction( "_chain_cover_index", self._calculate_chain_cover_txn, room_id, depth, stream, batch_size=None, single_room=True, ) total_rows_processed += result.processed_count if finished: await self.db_pool.updates._end_background_update("chain_cover") return total_rows_processed await self.db_pool.updates._background_update_progress( "chain_cover", { "current_room_id": current_room_id, "last_depth": last_depth, "last_stream": last_stream, }, ) return total_rows_processed def _calculate_chain_cover_txn( self, txn: Cursor, last_room_id: str, last_depth: int, last_stream: int, batch_size: Optional[int], single_room: bool, ) -> _CalculateChainCover: """Calculate the chain cover for `batch_size` events, ordered by `(room_id, depth, stream)`. Args: txn, last_room_id, last_depth, last_stream: The `(room_id, depth, stream)` tuple to fetch results after. batch_size: The maximum number of events to process. If None then no limit. single_room: Whether to calculate the index for just the given room. """ # Get the next set of events in the room (that we haven't already # computed chain cover for). We do this in topological order. # We want to do a `(topological_ordering, stream_ordering) > (?,?)` # comparison, but that is not supported on older SQLite versions tuple_clause, tuple_args = make_tuple_comparison_clause( [ ("events.room_id", last_room_id), ("topological_ordering", last_depth), ("stream_ordering", last_stream), ], ) extra_clause = "" if single_room: extra_clause = "AND events.room_id = ?" tuple_args.append(last_room_id) sql = """ SELECT event_id, state_events.type, state_events.state_key, topological_ordering, stream_ordering, events.room_id FROM events INNER JOIN state_events USING (event_id) LEFT JOIN event_auth_chains USING (event_id) LEFT JOIN event_auth_chain_to_calculate USING (event_id) WHERE event_auth_chains.event_id IS NULL AND event_auth_chain_to_calculate.event_id IS NULL AND %(tuple_cmp)s %(extra)s ORDER BY events.room_id, topological_ordering, stream_ordering %(limit)s """ % { "tuple_cmp": tuple_clause, "limit": "LIMIT ?" if batch_size is not None else "", "extra": extra_clause, } if batch_size is not None: tuple_args.append(batch_size) txn.execute(sql, tuple_args) rows = txn.fetchall() # Put the results in the necessary format for # `_add_chain_cover_index` event_to_room_id = {row[0]: row[5] for row in rows} event_to_types = {row[0]: (row[1], row[2]) for row in rows} # Calculate the new last position we've processed up to. new_last_depth = rows[-1][3] if rows else last_depth # type: int new_last_stream = rows[-1][4] if rows else last_stream # type: int new_last_room_id = rows[-1][5] if rows else "" # type: str # Map from room_id to last depth/stream_ordering processed for the room, # excluding the last room (which we're likely still processing). We also # need to include the room passed in if it's not included in the result # set (as we then know we've processed all events in said room). # # This is the set of rooms that we can now safely flip the # `has_auth_chain_index` bit for. finished_rooms = { row[5]: (row[3], row[4]) for row in rows if row[5] != new_last_room_id } if last_room_id not in finished_rooms and last_room_id != new_last_room_id: finished_rooms[last_room_id] = (last_depth, last_stream) count = len(rows) # We also need to fetch the auth events for them. auth_events = self.db_pool.simple_select_many_txn( txn, table="event_auth", column="event_id", iterable=event_to_room_id, keyvalues={}, retcols=("event_id", "auth_id"), ) event_to_auth_chain = {} # type: Dict[str, List[str]] for row in auth_events: event_to_auth_chain.setdefault(row["event_id"], []).append(row["auth_id"]) # Calculate and persist the chain cover index for this set of events. # # Annoyingly we need to gut wrench into the persit event store so that # we can reuse the function to calculate the chain cover for rooms. PersistEventsStore._add_chain_cover_index( txn, self.db_pool, self.event_chain_id_gen, event_to_room_id, event_to_types, event_to_auth_chain, ) return _CalculateChainCover( room_id=new_last_room_id, depth=new_last_depth, stream=new_last_stream, processed_count=count, finished_room_map=finished_rooms, ) async def _purged_chain_cover_index(self, progress: dict, batch_size: int) -> int: """ A background updates that iterates over the chain cover and deletes the chain cover for events that have been purged. This may be due to fully purging a room or via setting a retention policy. """ current_event_id = progress.get("current_event_id", "") def purged_chain_cover_txn(txn) -> int: # The event ID from events will be null if the chain ID / sequence # number points to a purged event. sql = """ SELECT event_id, chain_id, sequence_number, e.event_id IS NOT NULL FROM event_auth_chains LEFT JOIN events AS e USING (event_id) WHERE event_id > ? ORDER BY event_auth_chains.event_id ASC LIMIT ? """ txn.execute(sql, (current_event_id, batch_size)) rows = txn.fetchall() if not rows: return 0 # The event IDs and chain IDs / sequence numbers where the event has # been purged. unreferenced_event_ids = [] unreferenced_chain_id_tuples = [] event_id = "" for event_id, chain_id, sequence_number, has_event in rows: if not has_event: unreferenced_event_ids.append((event_id,)) unreferenced_chain_id_tuples.append((chain_id, sequence_number)) # Delete the unreferenced auth chains from event_auth_chain_links and # event_auth_chains. txn.executemany( """ DELETE FROM event_auth_chains WHERE event_id = ? """, unreferenced_event_ids, ) # We should also delete matching target_*, but there is no index on # target_chain_id. Hopefully any purged events are due to a room # being fully purged and they will be removed from the origin_* # searches. txn.executemany( """ DELETE FROM event_auth_chain_links WHERE origin_chain_id = ? AND origin_sequence_number = ? """, unreferenced_chain_id_tuples, ) progress = { "current_event_id": event_id, } self.db_pool.updates._background_update_progress_txn( txn, "purged_chain_cover", progress ) return len(rows) result = await self.db_pool.runInteraction( "_purged_chain_cover_index", purged_chain_cover_txn, ) if not result: await self.db_pool.updates._end_background_update("purged_chain_cover") return result