Wrap all of get_app_service_rooms in a txn.

synapse/storage/roommember.py

@@ -180,6 +180,14 @@ class RoomMemberStore(SQLBaseStore):
         if not membership_list:
             return defer.succeed(None)
 
+        return self.runInteraction(
+            "get_rooms_for_user_where_membership_is",
+            self._get_rooms_for_user_where_membership_is_txn,
+            user_id, membership_list
+        )
+
+    def _get_rooms_for_user_where_membership_is_txn(self, txn, user_id,
+                                                   membership_list):
         where_clause = "user_id = ? AND (%s)" % (
             " OR ".join(["membership = ?" for _ in membership_list]),
         )
@@ -187,24 +195,18 @@ class RoomMemberStore(SQLBaseStore):
         args = [user_id]
         args.extend(membership_list)
 
-        def f(txn):
-            sql = (
-                "SELECT m.room_id, m.sender, m.membership"
-                " FROM room_memberships as m"
-                " INNER JOIN current_state_events as c"
-                " ON m.event_id = c.event_id"
-                " WHERE %s"
-            ) % (where_clause,)
+        sql = (
+            "SELECT m.room_id, m.sender, m.membership"
+            " FROM room_memberships as m"
+            " INNER JOIN current_state_events as c"
+            " ON m.event_id = c.event_id"
+            " WHERE %s"
+        ) % (where_clause,)
 
-            txn.execute(sql, args)
-            return [
-                RoomsForUser(**r) for r in self.cursor_to_dict(txn)
-            ]
-
-        return self.runInteraction(
-            "get_rooms_for_user_where_membership_is",
-            f
-        )
+        txn.execute(sql, args)
+        return [
+            RoomsForUser(**r) for r in self.cursor_to_dict(txn)
+        ]
 
     def get_joined_hosts_for_room(self, room_id):
         return self._simple_select_onecol(