diff --git a/synapse/storage/databases/main/events_bg_updates.py b/synapse/storage/databases/main/events_bg_updates.py
index cb6b1f8a0c..73e69d4cb1 100644
--- a/synapse/storage/databases/main/events_bg_updates.py
+++ b/synapse/storage/databases/main/events_bg_updates.py
@@ -135,6 +135,11 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
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"]
@@ -932,3 +937,77 @@ class EventsBackgroundUpdatesStore(SQLBaseStore):
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
diff --git a/synapse/storage/databases/main/purge_events.py b/synapse/storage/databases/main/purge_events.py
index 0836e4af49..41f4fe7f95 100644
--- a/synapse/storage/databases/main/purge_events.py
+++ b/synapse/storage/databases/main/purge_events.py
@@ -331,13 +331,9 @@ class PurgeEventsStore(StateGroupWorkerStore, SQLBaseStore):
txn.executemany(
"""
DELETE FROM event_auth_chain_links WHERE
- (origin_chain_id = ? AND origin_sequence_number = ?) OR
- (target_chain_id = ? AND target_sequence_number = ?)
+ origin_chain_id = ? AND origin_sequence_number = ?
""",
- (
- (chain_id, seq_num, chain_id, seq_num)
- for (chain_id, seq_num) in referenced_chain_id_tuples
- ),
+ referenced_chain_id_tuples,
)
# Now we delete tables which lack an index on room_id but have one on event_id
diff --git a/synapse/storage/databases/main/schema/delta/59/10delete_purged_chain_cover.sql b/synapse/storage/databases/main/schema/delta/59/10delete_purged_chain_cover.sql
new file mode 100644
index 0000000000..87cb1f3cfd
--- /dev/null
+++ b/synapse/storage/databases/main/schema/delta/59/10delete_purged_chain_cover.sql
@@ -0,0 +1,17 @@
+/* Copyright 2021 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 (ordering, update_name, progress_json) VALUES
+ (5910, 'purged_chain_cover', '{}');
|
