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To: Pavan Deolasee <pavan.deolasee@gmail.com>
cc: =?ISO-8859-1?Q?C=E9dric_Villemain?= <cedric.villemain.debian@gmail.com>,
	Greg Stark <gsstark@mit.edu>, Robert Haas <robertmhaas@gmail.com>,
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	Florian Helmberger <fh@25th-floor.com>,
	Alvaro Herrera <alvherre@commandprompt.com>, pgsql-hackers@postgresql.org
Subject: Re: [ADMIN] pg_class reltuples/relpages not updated by
	autovacuum/vacuum
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Comments: In-reply-to Pavan Deolasee <pavan.deolasee@gmail.com>
	message dated "Sun, 29 May 2011 21:18:42 +0530"
Date: Sun, 29 May 2011 11:57:01 -0400
Message-ID: <21060.1306684621@sss.pgh.pa.us>
From: Tom Lane <tgl@sss.pgh.pa.us>
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Pavan Deolasee <pavan.deolasee@gmail.com> writes:
> On Sun, May 29, 2011 at 8:10 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> That would require proof, not just suggestion.  Skipping pages will
>> defeat the OS read-ahead algorithm, and so could easily cost more than
>> reading them.

> My worry is what we have right now is also based on just assumptions
> and gut feelings rather than any numbers.

So go collect some numbers.

			regards, tom lane