As I mentioned in [1], I've had a few cases recently about auto-vacuum not working. On the other thread, it was all about auto-vacuum being configured to run too slowly. The other culprit for auto-vacuum not working is when people periodically use pg_stat_reset().
The problem with pg_stat_reset() is that it zeros n_dead_tup and n_mod_since_analyze. If say a user resets the stats on a monthly basis then this can mean that tables that normally receive an auto-vacuum any less frequently than once per month could never receive an auto-vacuum... at least not until an anti-wraparound vacuum gets hold of it. The best I can think to do to try and avoid this is to put a giant WARNING in the docs about either not using it or to at least run ANALYZE after using it. Does anyone else think this is a problem worth trying to solve? [1] https://www.postgresql.org/message-id/CAKJS1f_YbXC2qTMPyCbmsPiKvZYwpuQNQMohiRXLj1r=8_r...@mail.gmail.com -- David Rowley http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Training & Services
