The load tests (#133) found a daemon on SQLite scanning 1.3s a feed of 20 items served from the
same machine: 1,500 feeds would have taken about 50 minutes. On Tower's /tmp, a loop device, one
synchronous 4 KB write takes 52ms, and SQLite was in WAL mode with its default synchronous=FULL,
which waits for the disk on every commit; nearly every statement is a commit of its own, a
feed's entries and enclosures being written a row at a time. Subscribing the first admin to an
imported catalogue of 1,500 feeds took 39s, before the web server listened.
Every SQLite connection now sets synchronous=NORMAL, SQLite's own advice for WAL: it syncs at
checkpoints. A crash of ipx loses nothing; a power cut can lose the last transactions, and never
corrupts the file. The same scan takes 27s and the same subscribing 0.75s. Postgres, which
production runs on, is unaffected.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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