Ensure that the background tasks have access to the proper stores.

synapse/app/generic_worker.py

@@ -133,6 +133,7 @@ from synapse.storage.databases.main.monthly_active_users import (
 )
 from synapse.storage.databases.main.presence import UserPresenceState
 from synapse.storage.databases.main.search import SearchWorkerStore
+from synapse.storage.databases.main.stats import StatsStore
 from synapse.storage.databases.main.ui_auth import UIAuthWorkerStore
 from synapse.storage.databases.main.user_directory import UserDirectoryStore
 from synapse.types import ReadReceipt
@@ -454,6 +455,7 @@ class GenericWorkerSlavedStore(
     # FIXME(#3714): We need to add UserDirectoryStore as we write directly
     # rather than going via the correct worker.
     UserDirectoryStore,
+    StatsStore,
     UIAuthWorkerStore,
     SlavedDeviceInboxStore,
     SlavedDeviceStore,

synapse/storage/databases/main/ui_auth.py

@@ -288,8 +288,6 @@ class UIAuthWorkerStore(SQLBaseStore):
         )
         return [(row["user_agent"], row["ip"]) for row in rows]
 
-
-class UIAuthStore(UIAuthWorkerStore):
     async def delete_old_ui_auth_sessions(self, expiration_time: int) -> None:
         """
         Remove sessions which were last used earlier than the expiration time.
@@ -339,3 +337,7 @@ class UIAuthStore(UIAuthWorkerStore):
             iterable=session_ids,
             keyvalues={},
         )
+
+
+class UIAuthStore(UIAuthWorkerStore):
+    pass