Update the extremeties tables in a seperate txn

synapse/storage/event_federation.py

@@ -303,10 +303,13 @@ class EventFederationStore(SQLBaseStore):
             ],
         )
 
+    @defer.inlineCallbacks
+    def _update_extremeties(self, events):
         events_by_room = {}
         for ev in events:
             events_by_room.setdefault(ev.room_id, []).append(ev)
 
+        def _update_forwards_txn(txn):
             for room_id, room_events in events_by_room.items():
                 prevs = [
                     e_id for ev in room_events for e_id, _ in ev.prev_events
@@ -337,6 +340,7 @@ class EventFederationStore(SQLBaseStore):
                 ]
             )
 
+        def _update_backwards_txn(txn):
             query = (
                 "INSERT INTO event_backward_extremities (event_id, room_id)"
                 " SELECT ?, ? WHERE NOT EXISTS ("
@@ -372,6 +376,9 @@ class EventFederationStore(SQLBaseStore):
                     self.get_latest_event_ids_in_room.invalidate, (room_id,)
                 )
 
+        yield self.runInteraction("_update_forwards_txn", _update_forwards_txn)
+        yield self.runInteraction("_update_backwards_txn", _update_backwards_txn)
+
     def get_backfill_events(self, room_id, event_list, limit):
         """Get a list of Events for a given topic that occurred before (and
         including) the events in event_list. Return a list of max size `limit`

synapse/storage/events.py

@@ -86,6 +86,10 @@ class EventsStore(SQLBaseStore):
                     is_new_state=is_new_state,
                 )
 
+                yield self._update_extremeties([
+                    ev for ev, _ in chunk
+                ])
+
     @defer.inlineCallbacks
     @log_function
     def persist_event(self, event, context, backfilled=False,
@@ -120,6 +124,8 @@ class EventsStore(SQLBaseStore):
         except _RollbackButIsFineException:
             pass
 
+        yield self._update_extremeties([event])
+
         max_persisted_id = yield self._stream_id_gen.get_max_token(self)
         defer.returnValue((stream_ordering, max_persisted_id))