1 files changed, 2 insertions, 2 deletions
diff --git a/synapse/storage/databases/main/state.py b/synapse/storage/databases/main/state.py
index 991233a9bc..458f169617 100644
--- a/synapse/storage/databases/main/state.py
+++ b/synapse/storage/databases/main/state.py
@@ -260,8 +260,8 @@ class StateGroupWorkerStore(EventsWorkerStore, SQLBaseStore):
         return event.content.get("canonical_alias")
 
     @cached(max_entries=50000)
-    def _get_state_group_for_event(self, event_id):
-        return self.db_pool.simple_select_one_onecol(
+    async def _get_state_group_for_event(self, event_id: str) -> Optional[int]:
+        return await self.db_pool.simple_select_one_onecol(
             table="event_to_state_groups",
             keyvalues={"event_id": event_id},
             retcol="state_group",