In case you were wondering why silo.pub were down for ages, the database had finally filled up the disk. I eventually willed myself out of entropy and wrote a cron job to delete entries older than a year (or more than 2000th in their feed, from e.g. twitter-atom)
DELETE FROM entryDELETE FROM entry USING ( SELECT id, ROW_NUMBER() OVER (PARTITION BY feed_id ORDER BY retrieved DESC) AS row FROM entry ) AS numbered WHERE entry.id = numbered.id AND (row > 2000 OR retrieved < CURRENT_DATE - INTERVAL '365 days');
12:08pm PDT