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From: Michael Stone <mstone+postgres@mathom.us>
To: pgsql-performance@postgresql.org
Subject: Re: Forcing using index instead of sequential scan?
Date: Sun, 23 Jul 2006 07:07:26 -0400
Message-ID: <20060723110724.GU8069@mathom.us> (raw)
In-Reply-To: <44C25FDD.8070003@modgraph-usa.com>
References: <D012B9600FFB984AB18C0D53C475A4A081F51B@E03MVZ3-UKDY.domain1.systemhost.net>
	<26827.1153585341@sss.pgh.pa.us>
	<44C25FDD.8070003@modgraph-usa.com>

On Sat, Jul 22, 2006 at 10:26:53AM -0700, Craig A. James wrote:
>This causes massive file-system activity and flushes all files that the 
>kernel has cached.  If you run this between each Postgres test (let it run 
>for a couple minutes), it gives you an apples-to-apples comparison between 
>successive benchmarks, and eliminates the effects of caching.

Assuming a system with small ram or an unusually large system 
installation. Unmounting is a much more realiable mechanism.

Mike Stone



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