Use partial indices on SQLIte. (#13802)

Partial indices have been supported since SQLite 3.8, but Synapse
now requires >= 3.27, so we can enable support for them.

This requires rebuilding previous indices which were partial on
PostgreSQL, but not on SQLite.

1 files changed, 56 insertions, 0 deletions

diff --git a/synapse/storage/schema/main/delta/72/09partial_indices.sql.sqlite b/synapse/storage/schema/main/delta/72/09partial_indices.sql.sqlite
new file mode 100644
index 0000000000..c8dfdf0218
--- /dev/null
+++ b/synapse/storage/schema/main/delta/72/09partial_indices.sql.sqlite
@@ -0,0 +1,56 @@
+/* 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.
+ */
+ 
+-- SQLite needs to rebuild indices which use partial indices on Postgres, but
+-- previously did not use them on SQLite.
+
+-- Drop each index that was added with register_background_index_update AND specified
+-- a where_clause (that existed before this delta).
+
+-- From events_bg_updates.py
+DROP INDEX IF EXISTS event_contains_url_index;
+-- There is also a redactions_censored_redacts index, but that gets dropped.
+DROP INDEX IF EXISTS redactions_have_censored_ts;
+-- There is also a PostgreSQL only index (event_contains_url_index2)
+-- which gets renamed to event_contains_url_index.
+
+-- From roommember.py
+DROP INDEX IF EXISTS room_memberships_user_room_forgotten;
+
+-- From presence.py
+DROP INDEX IF EXISTS presence_stream_state_not_offline_idx;
+
+-- From media_repository.py
+DROP INDEX IF EXISTS local_media_repository_url_idx;
+
+-- From event_push_actions.py
+DROP INDEX IF EXISTS event_push_actions_highlights_index;
+-- There's also a event_push_actions_stream_highlight_index which was previously
+-- PostgreSQL-only.
+
+-- From state.py
+DROP INDEX IF EXISTS current_state_events_member_index;
+
+-- Re-insert the background jobs to re-create the indices.
+INSERT INTO background_updates (ordering, update_name, progress_json, depends_on) VALUES
+  (7209, 'event_contains_url_index', '{}', NULL),
+  (7209, 'redactions_have_censored_ts_idx', '{}', NULL),
+  (7209, 'room_membership_forgotten_idx', '{}', NULL),
+  (7209, 'presence_stream_not_offline_index', '{}', NULL),
+  (7209, 'local_media_repository_url_idx', '{}', NULL),
+  (7209, 'event_push_actions_highlights_index', '{}', NULL),
+  (7209, 'event_push_actions_stream_highlight_index', '{}', NULL),
+  (7209, 'current_state_members_idx', '{}', NULL)
+ON CONFLICT (update_name) DO NOTHING;