Faster joins: Update room stats and user directory on workers when done

When finishing a partial state join to a room, we update the current state of the room without persisting additional events. Workers receive notice of the current state update over replication, but neglect to wake the room stats and user directory updaters, which then get incidentally triggered the next time an event is persisted or an unrelated event persister sends out a stream position update. We wake the room stats and user directory updaters at the appropriate time in this commit. Part of #12814 and #12815. Signed-off-by: Sean Quah <[email protected]>
matrix-org · Jan 19, 2023 · e921504 · e921504
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commit e921504
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diff --git a/changelog.d/14874.bugfix b/changelog.d/14874.bugfix
@@ -0,0 +1 @@
+Faster joins: Fix a bug in worker deployments where the room stats and user directory would not get updated when finishing a fast join until another event is sent or received.
diff --git a/synapse/handlers/federation.py b/synapse/handlers/federation.py
@@ -1735,10 +1735,6 @@ async def _sync_partial_state_room(
                     # Poke the notifier so that other workers see the write to
                     # the un-partial-stated rooms stream.
                     self._notifier.notify_replication()
-
-                    # TODO(faster_joins) update room stats and user directory?
-                    #   https://github.com/matrix-org/synapse/issues/12814
-                    #   https://github.com/matrix-org/synapse/issues/12815
                     return
 
                 # we raced against more events arriving with partial state. Go round

diff --git a/synapse/replication/tcp/client.py b/synapse/replication/tcp/client.py
@@ -207,6 +207,11 @@ async def on_rdata(
             # we don't need to optimise this for multiple rows.
             for row in rows:
                 if row.type != EventsStreamEventRow.TypeId:
+                    # The row's data is an `EventsStreamCurrentStateRow`.
+                    # When finishing up a partial state join, the current state of a
+                    # room will change without any new events being persisted, so we
+                    # must poke the replication callbacks ourselves.
+                    self.notifier.notify_replication()
                     continue
                 assert isinstance(row, EventsStreamRow)
                 assert isinstance(row.data, EventsStreamEventRow)

diff --git a/synapse/storage/controllers/state.py b/synapse/storage/controllers/state.py
@@ -493,8 +493,6 @@ async def get_current_state_deltas(
                  up to date.
         """
         # FIXME(faster_joins): what do we do here?
-        #   https://github.com/matrix-org/synapse/issues/12814
-        #   https://github.com/matrix-org/synapse/issues/12815
         #   https://github.com/matrix-org/synapse/issues/13008
 
         return await self.stores.main.get_partial_current_state_deltas(