Preparatory work for tweaking performance of auth chain lookups (#16833)

2 files changed, 34 insertions, 0 deletions

diff --git a/synapse/storage/schema/main/delta/84/01_auth_links_stats.sql.postgres b/synapse/storage/schema/main/delta/84/01_auth_links_stats.sql.postgres
new file mode 100644
index 0000000000..b0b41bd106
--- /dev/null
+++ b/synapse/storage/schema/main/delta/84/01_auth_links_stats.sql.postgres
@@ -0,0 +1,18 @@
+--
+-- 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>.
+
+-- Force the statistics for these tables to show that the number of distinct
+-- chain IDs are proportional to the total rows, as postgres has trouble
+-- figuring that out by itself.
+ALTER TABLE event_auth_chain_links ALTER origin_chain_id SET (n_distinct = -0.5);
+ALTER TABLE event_auth_chain_links ALTER target_chain_id SET (n_distinct = -0.5);
diff --git a/synapse/storage/schema/main/delta/84/02_auth_links_index.sql b/synapse/storage/schema/main/delta/84/02_auth_links_index.sql
new file mode 100644
index 0000000000..6936e3d05b
--- /dev/null
+++ b/synapse/storage/schema/main/delta/84/02_auth_links_index.sql
@@ -0,0 +1,16 @@
+--
+-- 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
+    (8402, 'event_auth_chain_links_origin_index', '{}');