From: Josh Berkus <josh@agliodbs.com>
To: Ron Peacetree <rjpeace@earthlink.net>
Cc: Dann Corbit <DCorbit@connx.com>
Cc: pgsql-hackers@postgresql.org
Cc: pgsql-performance@postgresql.org
Subject: Re: [PERFORM] A Better External Sort?
Date: Tue, 27 Sep 2005 09:15:06 -0700
Message-ID: <4339700A.2030803@agliodbs.com> (raw)
In-Reply-To: <19483839.1127783447942.JavaMail.root@elwamui-polski.atl.sa.earthlink.net>
References: <19483839.1127783447942.JavaMail.root@elwamui-polski.atl.sa.earthlink.net>
Ron,
I've somehow missed part of this thread, which is a shame since this is
an area of primary concern for me.
Your suggested algorithm seems to be designed to relieve I/O load by
making more use of the CPU. (if I followed it correctly). However,
that's not PostgreSQL's problem; currently for us external sort is a
*CPU-bound* operation, half of which is value comparisons. (oprofiles
available if anyone cares)
So we need to look, instead, at algorithms which make better use of
work_mem to lower CPU activity, possibly even at the expense of I/O.
--Josh Berkus
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To: pgsql-performance@postgresql.org
Cc: josh@agliodbs.com, rjpeace@earthlink.net, DCorbit@connx.com, pgsql-hackers@postgresql.org
Subject: Re: [PERFORM] A Better External Sort?
In-Reply-To: <4339700A.2030803@agliodbs.com>
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