diff --git a/synapse/storage/events.py b/synapse/storage/events.py index b582942164..59f8061333 100644 --- a/synapse/storage/events.py +++ b/synapse/storage/events.py @@ -1411,11 +1411,21 @@ class EventsStore(SQLBaseStore): to_delete ) + txn.execute( + "SELECT event_id FROM event_backward_extremities WHERE room_id = ?", + (room_id,) + ) + + cur_back_event_ids = [event_id for event_id, in txn.fetchall()] + # Update backward extremeties txn.executemany( "INSERT INTO event_backward_extremities (room_id, event_id)" " VALUES (?, ?)", - [(room_id, event_id) for event_id, in new_backwards_extrems] + [ + (room_id, event_id) for event_id, in new_backwards_extrems + if event_id not in cur_back_event_ids + ] ) txn.executemany(