Add another index to `device_lists_changes_in_room` (#14534)

This helps avoid reading unnecessarily large amounts of data from the
table when querying with a set of room IDs.

1 files changed, 20 insertions, 0 deletions

diff --git a/synapse/storage/schema/main/delta/73/13add_device_lists_index.sql b/synapse/storage/schema/main/delta/73/13add_device_lists_index.sql
new file mode 100644

index 0000000000..3725022a13
--- /dev/null
+++ b/synapse/storage/schema/main/delta/73/13add_device_lists_index.sql
@@ -0,0 +1,20 @@
+/* Copyright 2022 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.
+ */
+
+
+-- Adds an index on `device_lists_changes_in_room (room_id, stream_id)`, which
+-- speeds up `/sync` queries.
+INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
+  (7313, 'device_lists_changes_in_room_by_room_index', '{}');