From: Stephan Szabo <sszabo@megazone.bigpanda.com>
To: Luke Lonergan <LLonergan@greenplum.com>
Cc: Charlie Savage <cfis@interserv.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Sort performance on large tables
Date: Tue, 8 Nov 2005 09:38:21 -0800 (PST)
Message-ID: <20051108093500.N31541@megazone.bigpanda.com> (raw)
In-Reply-To: <3E37B936B592014B978C4415F90D662D0193B9F0@MI8NYCMAIL06.Mi8.com>
References: <3E37B936B592014B978C4415F90D662D0193B9F0@MI8NYCMAIL06.Mi8.com>
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.
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To: pgsql-performance@postgresql.org
Cc: sszabo@megazone.bigpanda.com, LLonergan@greenplum.com, cfis@interserv.com
Subject: Re: Sort performance on large tables
In-Reply-To: <20051108093500.N31541@megazone.bigpanda.com>
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