Add ReadWriteLock for pagination and history prune

synapse/handlers/message.py

@@ -26,7 +26,7 @@ from synapse.types import (
     UserID, RoomAlias, RoomStreamToken, StreamToken, get_domain_from_id
 )
 from synapse.util import unwrapFirstError
-from synapse.util.async import concurrently_execute, run_on_reactor
+from synapse.util.async import concurrently_execute, run_on_reactor, ReadWriteLock
 from synapse.util.caches.snapshot_cache import SnapshotCache
 from synapse.util.logcontext import preserve_fn
 from synapse.visibility import filter_events_for_client
@@ -50,6 +50,8 @@ class MessageHandler(BaseHandler):
         self.validator = EventValidator()
         self.snapshot_cache = SnapshotCache()
 
+        self.pagination_lock = ReadWriteLock()
+
     @defer.inlineCallbacks
     def purge_history(self, room_id, event_id):
         event = yield self.store.get_event(event_id)
@@ -59,8 +61,7 @@ class MessageHandler(BaseHandler):
 
         depth = event.depth
 
-        # TODO: Lock.
-
+        with (yield self.pagination_lock.write(room_id)):
             yield self.store.delete_old_state(room_id, depth)
 
     @defer.inlineCallbacks
@@ -98,6 +99,7 @@ class MessageHandler(BaseHandler):
 
         source_config = pagin_config.get_source_config("room")
 
+        with (yield self.pagination_lock.read(room_id)):
             membership, member_event_id = yield self._check_in_room_or_world_readable(
                 room_id, user_id
             )
@@ -108,7 +110,7 @@ class MessageHandler(BaseHandler):
                 if room_token.topological:
                     max_topo = room_token.topological
                 else:
-                max_topo = yield self.store.get_max_topological_token_for_stream_and_room(
+                    max_topo = yield self.store.get_max_topological_token(
                         room_id, room_token.stream
                     )
 

synapse/storage/stream.py

@@ -487,13 +487,13 @@ class StreamStore(SQLBaseStore):
             row["topological_ordering"], row["stream_ordering"],)
         )
 
-    def get_max_topological_token_for_stream_and_room(self, room_id, stream_key):
+    def get_max_topological_token(self, room_id, stream_key):
         sql = (
             "SELECT max(topological_ordering) FROM events"
             " WHERE room_id = ? AND stream_ordering < ?"
         )
         return self._execute(
-            "get_max_topological_token_for_stream_and_room", None,
+            "get_max_topological_token", None,
             sql, room_id, stream_key,
         ).addCallback(
             lambda r: r[0][0] if r else 0