Every room visit and every reconnection asks for the messages updated
since the page was rendered. That query filtered the room by updated_at
and sorted it by created_at, so SQLite walked every message in the room:
about 220-360 ms in a room of a million messages. An index on
(room_id, updated_at) finds the few updated messages directly.
Sorting on +created_at keeps SQLite on that index once messages are also
indexed by (room_id, created_at): with both, the planner otherwise walks
the room in creation order looking for updated rows.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JVFo3Lt9T8M5NR7KxVvsZ2
Search showed the last 100 matches by created_at, so SQLite collected every
message containing the words and sorted them before keeping a page. A common
word in a large account meant sorting most of its history on every search.
Ordering by the full-text index's rowid, which is the message id, lets SQLite
walk the index from the newest match and stop once the page is full.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01JVFo3Lt9T8M5NR7KxVvsZ2
GPT on behalf of DHH
Marcello Costagliola
Kevin McConnell