Re: postgresql meltdown on PlanetMath.org
Sean Chittenden <sean@chittenden.org>
From: Sean Chittenden <sean@chittenden.org>
To: Neil Conway <neilc@samurai.com>
Cc: logan@datacurrent.com, pgsql-performance@postgresql.org
Date: 2003-03-17T06:29:29Z
Lists: pgsql-performance
> >> A "select count(*) FROM tblwordidx" initially took about 1 second to > >> return a count of 2 million but after a few months it took several > >> minutes of really hard HDD grinding. > > > > That's because there are dead entries in the index that weren't being > > reused or cleaned up. As I said, this has been fixed. > > That's doubtful: "select count(*) FROM foo" won't use an > index. There are a bunch of other factors (e.g. dead heap tuples, > changes in the pages cached in the buffer, disk fragmentation, etc.) > that could effect performance in that situation, however. *blush* Yeah, jumped the gun on that when I read that queries were getting slower (churn of an index == slow creaping death for performance). A SELECT COUNT(*), however, wouldn't be affected by the index growth problem. Is the COUNT() on a view that uses an index? I haven't had any real problems with this kind of degredation outside of indexes. :-/ -sc -- Sean Chittenden