Re: Sort performance on large tables

On Tue, 8 Nov 2005, Luke Lonergan wrote:

> > SELECT tlid, min(ogc_fid)
> > FROM completechain
> > GROUP BY tlid
> > ORDER BY tlid;
> >
> > Even with this, it was more than a magnitude faster than Postgresql.
> > Which makes me think I have somehow misconfigured postgresql
> > (see the relevant parts of postgresql.conf below).
>
> Just as we find with a similar comparison (with a "popular commercial,
> proprietary database" :-) Though some might suggest you increase
> work_mem or other tuning suggestions to speed sorting, none work.  In
> fact, we find that increasing work_mem actually slows sorting slightly.

I wish you'd qualify your statements, because I can demonstrably show that
I can make sorts go faster on my machine at least by increasing work_mem
under some conditions.