Batch fetch bundled references (#14508)

Avoid an n+1 query problem and fetch the bundled aggregations for
m.reference relations in a single query instead of a query per event.

This applies similar logic for as was previously done for edits in
8b309adb436c162510ed1402f33b8741d71fc058 (#11660; threads
in b65acead428653b988351ae8d7b22127a22039cd (#11752); and
annotations in 1799a54a545618782840a60950ef4b64da9ee24d (#14491).

1 files changed, 4 insertions, 0 deletions

diff --git a/synapse/storage/databases/main/events.py b/synapse/storage/databases/main/events.py

index d68f127f9b..0f097a2927 100644
--- a/synapse/storage/databases/main/events.py
+++ b/synapse/storage/databases/main/events.py
@@ -2049,6 +2049,10 @@ class PersistEventsStore:
             self.store._invalidate_cache_and_stream(
                 txn, self.store.get_aggregation_groups_for_event, (redacted_relates_to,)
             )
+        if rel_type == RelationTypes.REFERENCE:
+            self.store._invalidate_cache_and_stream(
+                txn, self.store.get_references_for_event, (redacted_relates_to,)
+            )
         if rel_type == RelationTypes.REPLACE:
             self.store._invalidate_cache_and_stream(
                 txn, self.store.get_applicable_edit, (redacted_relates_to,)