Add forgotten schema delta (element-hq#17054)

This should have been in element-hq#17045. Whoops.

changelog.d/17054.misc

@@ -0,0 +1 @@
+Improve database performance by adding a missing index to `access_tokens.refresh_token_id`.

synapse/storage/databases/main/registration.py

@@ -2108,6 +2108,13 @@ def __init__(
             unique=False,
         )
 
+        self.db_pool.updates.register_background_index_update(
+            update_name="access_tokens_refresh_token_id_idx",
+            index_name="access_tokens_refresh_token_id_idx",
+            table="access_tokens",
+            columns=("refresh_token_id",),
+        )
+
     async def _background_update_set_deactivated_flag(
         self, progress: JsonDict, batch_size: int
     ) -> int:
@@ -2266,13 +2273,6 @@ def __init__(
     ):
         super().__init__(database, db_conn, hs)
 
-        self.db_pool.updates.register_background_index_update(
-            update_name="access_tokens_refresh_token_id_idx",
-            index_name="access_tokens_refresh_token_id_idx",
-            table="access_tokens",
-            columns=("refresh_token_id",),
-        )
-
         self._ignore_unknown_session_error = (
             hs.config.server.request_token_inhibit_3pid_errors
         )

synapse/storage/schema/main/delta/84/04_access_token_index.sql

@@ -0,0 +1,15 @@
+--
+-- This file is licensed under the Affero General Public License (AGPL) version 3.
+--
+-- Copyright (C) 2023 New Vector, Ltd
+--
+-- This program is free software: you can redistribute it and/or modify
+-- it under the terms of the GNU Affero General Public License as
+-- published by the Free Software Foundation, either version 3 of the
+-- License, or (at your option) any later version.
+--
+-- See the GNU Affero General Public License for more details:
+-- <https://www.gnu.org/licenses/agpl-3.0.html>.
+
+INSERT INTO background_updates (ordering, update_name, progress_json) VALUES
+    (8404, 'access_tokens_refresh_token_id_idx', '{}');