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To: "Jignesh K. Shah" <J.K.Shah@Sun.COM>
cc: pgsql-performance@postgresql.org, pgsql-hackers@postgresql.org
Subject: Re: [HACKERS] 8.3beta1 testing on Solaris 
In-reply-to: <4720FB72.8060800@sun.com> 
References: <4720FB72.8060800@sun.com>
Comments: In-reply-to "Jignesh K. Shah" <J.K.Shah@Sun.COM>
	message dated "Thu, 25 Oct 2007 16:24:18 -0400"
Date: Thu, 25 Oct 2007 16:54:01 -0400
Message-ID: <26010.1193345641@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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"Jignesh K. Shah" <J.K.Shah@Sun.COM> writes:
> CLOG data is 
> not cached in any PostgreSQL shared memory segments

The above statement is utterly false, so your trace seems to indicate
something broken.  Are you sure these were the only reads of pg_clog
files?  Can you extend the tracing to determine which page of the file
got read?  I am wondering if your (unspecified) test load was managing
to touch more pages of the clog than there is room for in shared memory.

			regards, tom lane