Re: Performance Tuning Document?

From: "Riebs, Andy" <Andy(dot)Riebs(at)compaq(dot)com>
To: "Matthew Kirkwood" <matthew(at)hairy(dot)beasts(dot)org>
Cc: <pgsql-general(at)postgresql(dot)org>
Subject: Re: Performance Tuning Document?
Date: 2002-03-28 18:09:44
Message-ID: F65B33CAD23A284EAE6E4AE353BF94DC01A8C650@tayexc13.americas.cpqcorp.net
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> Under the "crossSectionTests(Mixed IR)" part of an OSDB run, a
> large number of shared_buffers causes severe slowdown on one of
> the tests -- it goes from a little over 200 seconds to nearly
> 2000. I suspect internal lock contention, or maybe it's just
> that the read() path in Linux is quicker than PG's own cache?

Matthew, are you using the --postgresql=no_hash_index option for OSDB? It's conceivable that you are hitting an artifact of the hash index problem here.

/andy

---
Andy Riebs, andy(dot)riebs(at)compaq(dot)com High Performance Technical
(w) 603-884-1521, (fax) 603-884-0630 Computing/Linux Group
<http://cub.sourceforge.net/> Compaq Computer Corporation
(h) ariebs(at)earthlink(dot)net <http://www.compaq.com/linux>
<http://osdb.sourceforge.net/> <http://opensource.compaq.com>

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