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From: Simon Riggs <simon@2ndquadrant.com>
To: Tom Lane <tgl@sss.pgh.pa.us>
Cc: Heikki Linnakangas <heikki@enterprisedb.com>
Cc: Decibel! <decibel@decibel.org>
Cc: Greg Smith <gsmith@gregsmith.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: I/O on select count(*)
Date: Tue, 27 May 2008 21:54:26 +0100
Message-ID: <1211921666.4489.261.camel@ebony.site> (raw)
In-Reply-To: <21814.1211816217@sss.pgh.pa.us>
References: <920841.71690.qm@web44808.mail.sp1.yahoo.com>
	<482B1D5F.EE98.0025.0@wicourts.gov>
	<Pine.GSO.4.64.0805142133250.27290@westnet.com>
	<20080515020553.GN9838@alvh.no-ip.org>
	<Pine.LNX.4.64.0805151245360.16756@aragorn.flymine.org>
	<20080515155232.GC8221@alvh.no-ip.org>
	<Pine.GSO.4.64.0805161118210.4987@westnet.com>
	<20080516201528.GJ13061@alvh.no-ip.org>
	<18382.1210992302@sss.pgh.pa.us>
	<Pine.GSO.4.64.0805180113450.8667@westnet.com>
	<F16DFE65-7DC5-4D5A-9B18-4F6FA070ACD8@decibel.org>
	<483AB515.5050201@enterprisedb.com>
	<21814.1211816217@sss.pgh.pa.us>


On Mon, 2008-05-26 at 11:36 -0400, Tom Lane wrote:
> "Heikki Linnakangas" <heikki@enterprisedb.com> writes:
> > Decibel! wrote:
> >> Also, Simon and Tom had an idea at PGCon: Don't set hint-bits in the 
> >> back-end if the page isn't already dirty. 
> 
> > Or even better: set the hint-bits, but don't dirty the page.
> 
> Which in fact is what Simon suggested, not the other thing.

Just raised this on -hackers, BTW. 

-- 
 Simon Riggs           www.2ndQuadrant.com
 PostgreSQL Training, Services and Support

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