Process state deltas in presence by room

1 files changed, 15 insertions, 5 deletions

diff --git a/synapse/handlers/presence.py b/synapse/handlers/presence.py

index e9e0f1338f..1cbe65f72d 100644
--- a/synapse/handlers/presence.py
+++ b/synapse/handlers/presence.py
@@ -1183,7 +1183,16 @@ class PresenceHandler(BasePresenceHandler):
                 max_pos, deltas = await self.store.get_current_state_deltas(
                     self._event_pos, room_max_stream_ordering
                 )
-                await self._handle_state_delta(deltas)
+
+                # We may get multiple deltas for different rooms, but we want to
+                # handle them on a room by room basis, so we batch them up by
+                # room.
+                deltas_by_room: Dict[str, List[JsonDict]] = {}
+                for delta in deltas:
+                    deltas_by_room.setdefault(delta["room_id"], []).append(delta)
+
+                for room_id, deltas_for_room in deltas_by_room.items():
+                    await self._handle_state_delta(room_id, deltas_for_room)
 
                 self._event_pos = max_pos
 
@@ -1192,9 +1201,9 @@ class PresenceHandler(BasePresenceHandler):
                     max_pos
                 )
 
-    async def _handle_state_delta(self, deltas: List[JsonDict]) -> None:
-        """Process current state deltas to find new joins that need to be
-        handled.
+    async def _handle_state_delta(self, room_id: str, deltas: List[JsonDict]) -> None:
+        """Process current state deltas for the room to find new joins that need
+        to be handled.
         """
 
         # Sets of newly joined users. Note that if the local server is
@@ -1203,9 +1212,10 @@ class PresenceHandler(BasePresenceHandler):
         newly_joined_users = set()
 
         for delta in deltas:
+            assert room_id == delta["room_id"]
+
             typ = delta["type"]
             state_key = delta["state_key"]
-            room_id = delta["room_id"]
             event_id = delta["event_id"]
             prev_event_id = delta["prev_event_id"]