Jeff, Tom, >> Let's say that we had a range like 50-100M, where if it's older than >> 100M, we freeze it, and if it's older than 50M we freeze it only if it's >> on a dirty page. We would still have forensic evidence, but we could >> make a range such that we avoid writing multiple times. > > Yeah, making the limit "slushy" would doubtless save some writes, with > not a lot of downside.
This would mean two settings: vacuum_freeze_min_age and vacuum_freeze_dirty_age. And we'd need to add those to the the autovacuum settings for each table as well. While we could just make one setting 1/2 of the other, that prevents me from saying: "freeze this table agressively if it's in memory, but wait a long time to vaccuum if it's on disk" I can completely imagine a table which has a vacuum_freeze_dirty_age of 10000 and a vacuum_freeze_min_age of 1m. -- Josh Berkus PostgreSQL Experts Inc. www.pgexperts.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
