Drop the indexes in the background.

Author: clokep

synapse/storage/databases/main/event_push_actions.py

@@ -100,6 +100,7 @@
 )
 from synapse.storage.databases.main.receipts import ReceiptsWorkerStore
 from synapse.storage.databases.main.stream import StreamWorkerStore
+from synapse.types import JsonDict
 from synapse.util import json_encoder
 from synapse.util.caches.descriptors import cached
 
@@ -304,6 +305,39 @@ def __init__(
             table="event_push_summary",
         )
 
+        self.db_pool.updates.register_background_update_handler(
+            "event_push_drop_null_thread_id_indexes",
+            self._background_drop_null_thread_id_indexes,
+        )
+
+    async def _background_drop_null_thread_id_indexes(
+        self, progress: JsonDict, batch_size: int
+    ) -> int:
+        """
+        Drop the indexes used to find null thread_ids for event_push_actions and
+        event_push_summary.
+        """
+
+        def drop_null_thread_id_indexes_txn(
+            txn: LoggingTransaction, start_stream_ordering: int
+        ) -> None:
+            sql = "DROP INDEX IF EXISTS event_push_actions_thread_id_null"
+            logger.debug("[SQL] %s", sql)
+            txn.execute(sql)
+
+            sql = "DROP INDEX IF EXISTS event_push_summary_thread_id_null"
+            logger.debug("[SQL] %s", sql)
+            txn.execute(sql)
+
+        await self.db_pool.runInteraction(
+            "drop_null_thread_id_indexes_txn",
+            drop_null_thread_id_indexes_txn,
+        )
+        await self.db_pool.updates._end_background_update(
+            "event_push_drop_null_thread_id_indexes"
+        )
+        return 0
+
     async def get_unread_counts_by_room_for_user(self, user_id: str) -> Dict[str, int]:
         """Get the notification count by room for a user. Only considers notifications,
         not highlight or unread counts, and threads are currently aggregated under their room.

synapse/storage/schema/main/delta/76/05thread_notifications_not_null_event_push_actions.sql.postgres

@@ -25,6 +25,3 @@ ALTER TABLE event_push_actions
 -- only needs a SHARE UPDATE EXCLUSIVE lock but can still take a while to complete.
 INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
   (7605, 'event_push_actions_thread_id', '{}');
-
--- Drop the indexes used to find null thread_ids.
-DROP INDEX IF EXISTS event_push_actions_thread_id_null;

synapse/storage/schema/main/delta/76/05thread_notifications_not_null_event_push_summary.sql.postgres

@@ -24,7 +24,6 @@ ALTER TABLE event_push_summary
 -- We then validate the constraint which doesn't need to worry about new data. It
 -- only needs a SHARE UPDATE EXCLUSIVE lock but can still take a while to complete.
 INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
-  (7605, 'event_push_summary_thread_id', '{}');
-
--- Drop the indexes used to find null thread_ids.
-DROP INDEX IF EXISTS event_push_summary_thread_id_null;
+  (7605, 'event_push_summary_thread_id', '{}'),
+  -- Also clean-up the old indexes.
+  (7605, 'event_push_drop_null_thread_id_indexes', '{}');;