More detail on settings for pgavd?
Josh Berkus <josh@agliodbs.com>
From: Josh Berkus <josh@agliodbs.com>
To: Shridhar Daithankar <shridhar_daithankar@myrealbox.com>
Cc: pgsql-performance@postgresql.org
Date: 2003-11-18T23:58:45Z
Lists: pgsql-hackers, pgsql-performance
Shridhar, I was looking at the -V/-v and -A/-a settings in pgavd, and really don't understand how the calculation works. According to the readme, if I set -v to 1000 and -V to 2 (the defaults) for a table with 10,000 rows, pgavd would only vacuum after 21,000 rows had been updated. This seems wrong. Can you clear this up a little? I'd like to tweak these settings but can't without being better aquainted with the calculation. Also, you may want to reverse your default ratio for Vacuum/analyze frequency. True, analyze is a less expensive operation than Vacuum, but it's also needed less often -- only when the *distribution* of data changes. I've seen databases where the optimal vacuum/analyze frequency was every 10 min/once per day. -- -Josh Berkus Aglio Database Solutions San Francisco