User Cursor.__iter__ instead of fetchall

This prevents unnecessary construction of lists

1 files changed, 2 insertions, 2 deletions

diff --git a/synapse/storage/room.py b/synapse/storage/room.py

index 8a2fe2fdf5..e4c56cc175 100644
--- a/synapse/storage/room.py
+++ b/synapse/storage/room.py
@@ -396,7 +396,7 @@ class RoomStore(SQLBaseStore):
                     sql % ("AND appservice_id IS NULL",),
                     (stream_id,)
                 )
-            return dict(txn.fetchall())
+            return dict(txn)
         else:
             # We want to get from all lists, so we need to aggregate the results
 
@@ -422,7 +422,7 @@ class RoomStore(SQLBaseStore):
 
             results = {}
             # A room is visible if its visible on any list.
-            for room_id, visibility in txn.fetchall():
+            for room_id, visibility in txn:
                 results[room_id] = bool(visibility) or results.get(room_id, False)
 
             return results