From: Josh Berkus <josh@agliodbs.com>
To: pgsql-performance@postgresql.org
Cc: Jim C. Nasby <jnasby@pervasive.com>
Cc: Mischa Sandberg <mischa@ca.sophos.com>
Subject: Re: Solaris shared_buffers anomaly?
Date: Wed, 14 Jun 2006 14:25:04 -0700
Message-ID: <200606141425.04600.josh@agliodbs.com> (raw)
In-Reply-To: <20060614033539.GY34196@pervasive.com>
References: <1150151282.14661.42.camel@tigger>
<448F51DE.2070604@ca.sophos.com>
<20060614033539.GY34196@pervasive.com>
Folks,
First off, you'll be glad to know that I've persuaded two of the Sun
performance engineers to join this list soon. So you should be able to
get more difinitive answers to these questions.
Second, 7.4 still did linear scanning of shared_buffers as part of LRU and
for other activities. I don't know how that would cause swapping, but it
certainly could cause dramatic slowdowns (like 2-5x) if you overallocated
shared_buffers.
Possibly this is also triggering a bug in Solaris 2.6. 2.6 is pretty
darned old (1997); maybe you should upgrade? We're testing with s_b set
to 300,000 on Solaris 10 (Niagara) so this is obviously not a current
Solaris issue.
--
--Josh
Josh Berkus
PostgreSQL @ Sun
San Francisco
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To: pgsql-performance@postgresql.org
Cc: josh@agliodbs.com, jnasby@pervasive.com, mischa@ca.sophos.com
Subject: Re: Solaris shared_buffers anomaly?
In-Reply-To: <200606141425.04600.josh@agliodbs.com>
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