Prefill forward extrems and event to state groups

synapse/storage/events.py

@@ -403,6 +403,11 @@ class EventsStore(SQLBaseStore):
                         (room_id, ), new_state
                     )
 
+                for room_id, latest_event_ids in new_forward_extremeties.iteritems():
+                    self.get_latest_event_ids_in_room.prefill(
+                        (room_id,), latest_event_ids
+                    )
+
     @defer.inlineCallbacks
     def _calculate_new_extremeties(self, room_id, event_contexts, latest_event_ids):
         """Calculates the new forward extremeties for a room given events to

synapse/storage/state.py

@@ -315,6 +315,12 @@ class StateStore(SQLBaseStore):
             ],
         )
 
+        for event_id, state_group_id in state_groups.iteritems():
+            txn.call_after(
+                self._get_state_group_for_event.prefill,
+                (event_id,), state_group_id
+            )
+
     def _count_state_group_hops_txn(self, txn, state_group):
         """Given a state group, count how many hops there are in the tree.
 
@@ -584,8 +590,8 @@ class StateStore(SQLBaseStore):
         state_map = yield self.get_state_ids_for_events([event_id], types)
         defer.returnValue(state_map[event_id])
 
-    @cached(num_args=2, max_entries=50000)
-    def _get_state_group_for_event(self, room_id, event_id):
+    @cached(max_entries=50000)
+    def _get_state_group_for_event(self, event_id):
         return self._simple_select_one_onecol(
             table="event_to_state_groups",
             keyvalues={