Every message rewrote the row of every disconnected member of the room,
including the ones who were unread already and stay unread. Open rooms
take in the whole account, so in steady state that is every member on
every message: 325 WAL pages per post at 10,000 members, against 16 when
only the members who had read the room are written.
Directs keep touching all their members: a direct's sidebar row is
cached by its membership and carries the room's recency, so it has to
be refreshed on every message.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_017dFSDHrgrLoBELwjV3Qunq
Deleting the memberships with delete_all skips Membership's after_destroy_commit, which resets a member's
connections when one membership is revoked. Until the job ran, a member who had the room open kept its
streams, and a message that still landed in the room (a request already past the membership check, a bot's
reply) reached them. The request now reads the members' ids in the transaction that deletes their
memberships, and the job resets their connections before it destroys the messages. It costs a Redis round
trip per member, about 1.5 s for 10,000, so it's done in the job rather than in the request.
User#grant_membership_to_open_rooms read the open rooms and inserted in a separate statement, so a user
created while a room was being closed could read it as open and be granted it after the close. It's now a
single insert ... select, which SQLite runs under the write lock, skipping duplicates as insert_all did.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bj8KnxpTf9sj2Ysa8aLAVa
Room#destroy destroyed every message inside the room's own
transaction, which holds SQLite's write lock until the last one: on a
room with many messages, every other write in the app waited and
failed. The request now takes the room away from its members and
leaves the rest to Room::DestroyJob, which destroys the messages one
at a time, each in its own short transaction, and then the room.
An open room is closed in the request, so that someone who joins the
account before the job ends isn't given it.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01Bj8KnxpTf9sj2Ysa8aLAVa
Marcello Costagliola
Kevin McConnell