Bruce Momjian wrote: > On Wed, Apr 22, 2015 at 04:36:17PM +0100, Greg Stark wrote: > > On Mon, Apr 20, 2015 at 8:48 PM, Bruce Momjian <br...@momjian.us> wrote: > > > Well, we have to assume there are many misconfigured configurations --- > > > autovacuum isn't super-easy to configure, so we can't just blame the > > > user if this makes things worse. In fact, page pruning was designed > > > spefically for cases where autovacuum wasn't running our couldn't keep > > > up. > > > > Well autovacuum isn't currently considering HOT pruning part of its > > job at all. It's hard to call it "misconfigured" when there's > > literally *no* way to configure it "correctly". > > Good point, but doesn't vacuum remove the need for pruning as it removes > all the old rows?
Sure. The point, I think, is to make autovacuum runs of some sort that don't actually vacuum but only do HOT-pruning. Maybe this is a reasonable solution to the problem that queries don't prune anymore after Simon's patch. If we made autovac HOT-prune periodically, we could have read-only queries prune only already-dirty pages. Of course, that would need further adjustments to default number of autovac workers, I/O allocation, etc. -- Álvaro Herrera http://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
