Speed up purge room by adding index (#16657)

What it says on the tin

1 files changed, 17 insertions, 0 deletions

diff --git a/synapse/storage/schema/main/delta/83/06_event_push_summary_room.sql b/synapse/storage/schema/main/delta/83/06_event_push_summary_room.sql
new file mode 100644

index 0000000000..1aae1b7557
--- /dev/null
+++ b/synapse/storage/schema/main/delta/83/06_event_push_summary_room.sql
@@ -0,0 +1,17 @@
+/* Copyright 2023 The Matrix.org Foundation C.I.C
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
+    (8306, 'event_push_summary_index_room_id', '{}');