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, 37 insertions, 0 deletions

diff --git a/tests/storage/test_event_federation.py b/tests/storage/test_event_federation.py
index 81e50bdd55..4b8d8328d7 100644
--- a/tests/storage/test_event_federation.py
+++ b/tests/storage/test_event_federation.py
@@ -1134,6 +1134,43 @@ class EventFederationWorkerStoreTestCase(tests.unittest.HomeserverTestCase):
         backfill_event_ids = [backfill_point[0] for backfill_point in backfill_points]
         self.assertEqual(backfill_event_ids, ["insertion_eventA"])
 
+    def test_get_event_ids_with_failed_pull_attempts(self) -> None:
+        """
+        Test to make sure we properly get event_ids based on whether they have any
+        failed pull attempts.
+        """
+        # Create the room
+        user_id = self.register_user("alice", "test")
+        tok = self.login("alice", "test")
+        room_id = self.helper.create_room_as(room_creator=user_id, tok=tok)
+
+        self.get_success(
+            self.store.record_event_failed_pull_attempt(
+                room_id, "$failed_event_id1", "fake cause"
+            )
+        )
+        self.get_success(
+            self.store.record_event_failed_pull_attempt(
+                room_id, "$failed_event_id2", "fake cause"
+            )
+        )
+
+        event_ids_with_failed_pull_attempts = self.get_success(
+            self.store.get_event_ids_with_failed_pull_attempts(
+                event_ids=[
+                    "$failed_event_id1",
+                    "$fresh_event_id1",
+                    "$failed_event_id2",
+                    "$fresh_event_id2",
+                ]
+            )
+        )
+
+        self.assertEqual(
+            event_ids_with_failed_pull_attempts,
+            {"$failed_event_id1", "$failed_event_id2"},
+        )
+
     def test_get_event_ids_to_not_pull_from_backoff(self) -> None:
         """
         Test to make sure only event IDs we should backoff from are returned.