Process previously failed backfill events in the background (#15585)

Process previously failed backfill events in the background because they are bound to fail again and we don't need to waste time holding up the request for something that is bound to fail again.

Fix https://github.com/matrix-org/synapse/issues/13623

Follow-up to https://github.com/matrix-org/synapse/issues/13621 and https://github.com/matrix-org/synapse/issues/13622

Part of making `/messages` faster: https://github.com/matrix-org/synapse/issues/13356

1 files changed, 30 insertions, 1 deletions

diff --git a/synapse/storage/databases/main/event_federation.py b/synapse/storage/databases/main/event_federation.py
index ac19de183c..2681917d0b 100644
--- a/synapse/storage/databases/main/event_federation.py
+++ b/synapse/storage/databases/main/event_federation.py
@@ -46,7 +46,7 @@ from synapse.storage.database import (
 from synapse.storage.databases.main.events_worker import EventsWorkerStore
 from synapse.storage.databases.main.signatures import SignatureWorkerStore
 from synapse.storage.engines import PostgresEngine, Sqlite3Engine
-from synapse.types import JsonDict
+from synapse.types import JsonDict, StrCollection
 from synapse.util import json_encoder
 from synapse.util.caches.descriptors import cached
 from synapse.util.caches.lrucache import LruCache
@@ -1584,6 +1584,35 @@ class EventFederationWorkerStore(SignatureWorkerStore, EventsWorkerStore, SQLBas
         txn.execute(sql, (room_id, event_id, 1, self._clock.time_msec(), cause))
 
     @trace
+    async def get_event_ids_with_failed_pull_attempts(
+        self, event_ids: StrCollection
+    ) -> Set[str]:
+        """
+        Filter the given list of `event_ids` and return events which have any failed
+        pull attempts.
+
+        Args:
+            event_ids: A list of events to filter down.
+
+        Returns:
+            A filtered down list of `event_ids` that have previous failed pull attempts.
+        """
+
+        rows = await self.db_pool.simple_select_many_batch(
+            table="event_failed_pull_attempts",
+            column="event_id",
+            iterable=event_ids,
+            keyvalues={},
+            retcols=("event_id",),
+            desc="get_event_ids_with_failed_pull_attempts",
+        )
+        event_ids_with_failed_pull_attempts: Set[str] = {
+            row["event_id"] for row in rows
+        }
+
+        return event_ids_with_failed_pull_attempts
+
+    @trace
     async def get_event_ids_to_not_pull_from_backoff(
         self,
         room_id: str,