On 2016-08-23 19:33:33 -0300, Claudio Freire wrote:
> On Tue, Aug 23, 2016 at 7:20 PM, Andres Freund <andres@anarazel.de> wrote:
> >> Wouldn't more aggressive vacuuming of catalog tables fix the bloat?
> >
> > Not really in my experience, at least not without more drastic vacuum
> > changes. The issue is that if you have a single "long running"
> > transaction (in some workloads that can even just be a 3 min taking
> > query/xact), nothing will be cleaned up during that time. If you have a
> > few hundred temp tables created per sec, you'll be in trouble even
> > then. Not to speak of the case where you have queries taking hours (say
> > a backup).
>
> Well, my experience isn't as extreme as that (just a few dozen temp
> tables per minute), but when I see bloat in catalog tables it's
> because all autovacuum workers are stuck vacuuming huge tables for
> huge periods of time (hours or days).
Well, that's because our defaults are batshit stupid.