Reduce the amount of state we pull from the DB (#12811)

synapse/storage/controllers/state.py

@@ -455,3 +455,30 @@ class StateStorageController:
         return await self.stores.main.get_partial_current_state_deltas(
             prev_stream_id, max_stream_id
         )
+
+    async def get_current_state(
+        self, room_id: str, state_filter: Optional[StateFilter] = None
+    ) -> StateMap[EventBase]:
+        """Same as `get_current_state_ids` but also fetches the events"""
+        state_map_ids = await self.get_current_state_ids(room_id, state_filter)
+
+        event_map = await self.stores.main.get_events(list(state_map_ids.values()))
+
+        state_map = {}
+        for key, event_id in state_map_ids.items():
+            event = event_map.get(event_id)
+            if event:
+                state_map[key] = event
+
+        return state_map
+
+    async def get_current_state_event(
+        self, room_id: str, event_type: str, state_key: str
+    ) -> Optional[EventBase]:
+        """Get the current state event for the given type/state_key."""
+
+        key = (event_type, state_key)
+        state_map = await self.get_current_state(
+            room_id, StateFilter.from_types((key,))
+        )
+        return state_map.get(key)