1 files changed, 7 insertions, 0 deletions
diff --git a/synapse/storage/databases/main/account_data.py b/synapse/storage/databases/main/account_data.py
index 16c284807a..39498d52c6 100644
--- a/synapse/storage/databases/main/account_data.py
+++ b/synapse/storage/databases/main/account_data.py
@@ -103,6 +103,13 @@ class AccountDataWorkerStore(PushRulesWorkerStore, CacheInvalidationWorkerStore)
             "AccountDataAndTagsChangeCache", account_max
         )
 
+        self.db_pool.updates.register_background_index_update(
+            update_name="room_account_data_index_room_id",
+            index_name="room_account_data_room_id",
+            table="room_account_data",
+            columns=("room_id",),
+        )
+
         self.db_pool.updates.register_background_update_handler(
             "delete_account_data_for_deactivated_users",
             self._delete_account_data_for_deactivated_users,