From c16a981f22dd559b56caa94a46392c206be9a265 Mon Sep 17 00:00:00 2001 From: Erik Johnston Date: Wed, 16 Apr 2025 14:14:56 +0100 Subject: [PATCH] Fix query for room participation (#18345) Follow on from #18068 Currently the subquery in `UPDATE` is pointless, as it will still just update all `room_membership` rows. Instead, we should look at the current membership event ID (which is easily retrieved from `local_current_membership`). We also add a `AND NOT participant` to noop the `UPDATE` when the `participant` flag is already set. cc @H-Shay --- changelog.d/18345.bugfix | 1 + synapse/storage/databases/main/roommember.py | 20 ++++++++------------ 2 files changed, 9 insertions(+), 12 deletions(-) create mode 100644 changelog.d/18345.bugfix diff --git a/changelog.d/18345.bugfix b/changelog.d/18345.bugfix new file mode 100644 index 0000000000..c8a001d4a3 --- /dev/null +++ b/changelog.d/18345.bugfix @@ -0,0 +1 @@ +Fix minor performance regression caused by tracking of room participation. Regressed in v1.128.0. diff --git a/synapse/storage/databases/main/roommember.py b/synapse/storage/databases/main/roommember.py index a0a6dcd04e..dfa7dd48d9 100644 --- a/synapse/storage/databases/main/roommember.py +++ b/synapse/storage/databases/main/roommember.py @@ -1622,14 +1622,11 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore): sql = """ UPDATE room_memberships SET participant = true - WHERE (user_id, room_id) IN ( - SELECT user_id, room_id - FROM room_memberships - WHERE user_id = ? - AND room_id = ? - ORDER BY event_stream_ordering DESC - LIMIT 1 + WHERE event_id IN ( + SELECT event_id FROM local_current_membership + WHERE user_id = ? AND room_id = ? ) + AND NOT participant """ txn.execute(sql, (user_id, room_id)) @@ -1651,11 +1648,10 @@ class RoomMemberWorkerStore(EventsWorkerStore, CacheInvalidationWorkerStore): ) -> bool: sql = """ SELECT participant - FROM room_memberships - WHERE user_id = ? - AND room_id = ? - ORDER BY event_stream_ordering DESC - LIMIT 1 + FROM local_current_membership AS l + INNER JOIN room_memberships AS r USING (event_id) + WHERE l.user_id = ? + AND l.room_id = ? """ txn.execute(sql, (user_id, room_id)) res = txn.fetchone()