diff --git a/synapse/handlers/sync.py b/synapse/handlers/sync.py
index 6a8a117841..c3bd366240 100644
--- a/synapse/handlers/sync.py
+++ b/synapse/handlers/sync.py
@@ -1143,6 +1143,7 @@ class SyncHandler(object):
             # that were in a room we've left.
 
             logger.info("get_users_who_share_room... called from _generate_sync_entry")
+            logger.info("*Called with %s", user_id)
             users_who_share_room = await self.store.get_users_who_share_room_with_user(
                 user_id
             )
diff --git a/synapse/storage/data_stores/main/roommember.py b/synapse/storage/data_stores/main/roommember.py
index 2715540f7c..294d5410ad 100644
--- a/synapse/storage/data_stores/main/roommember.py
+++ b/synapse/storage/data_stores/main/roommember.py
@@ -486,7 +486,7 @@ class RoomMemberWorkerStore(EventsWorkerStore):
         )
         return frozenset(r.room_id for r in rooms)
 
-    @cachedInlineCallbacks(max_entries=500000, cache_context=True, iterable=True)
+    @cachedInlineCallbacks(max_entries=500000, cache_context=True)
     def get_users_who_share_room_with_user(self, user_id, cache_context):
         """Returns the set of users who share a room with `user_id`
         """