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From: Bruce Momjian <pgman@candle.pha.pa.us>
Message-Id: <200601201642.k0KGgBS23410@candle.pha.pa.us>
Subject: Re: Extremely irregular query performance
In-Reply-To: <18684.1137774889@sss.pgh.pa.us>
To: Tom Lane <tgl@sss.pgh.pa.us>
Date: Fri, 20 Jan 2006 11:42:11 -0500 (EST)
CC: Simon Riggs <simon@2ndquadrant.com>,
	=?ISO-8859-1?Q?Jean-Philippe_C=F4t=E9?=
	<jean-philippe.cote@crt.umontreal.ca>, pgsql-performance@postgresql.org
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Done, and paragraph added to 8.1.X.  (7.3 mention retained for 8.1.X.)

---------------------------------------------------------------------------

Tom Lane wrote:
> Bruce Momjian <pgman@candle.pha.pa.us> writes:
> >     <para>
> > !    Genetic query optimization (<acronym>GEQO</acronym>) randomly 
> > !    tests execution plans.  Therefore, when the number of tables 
> > !    exceeds <varname>geqo</> and genetic query optimization is in use,
> > !    the execution plan will change each time the statement is executed.
> >     </para>
> 
> geqo_threshold, please --- geqo is a boolean.
> 
> Possibly better wording:  Therefore, when the number of tables exceeds
> geqo_threshold causing genetic query optimization to be used, the
> execution plan is likely to change each time the statement is executed.
> 
> 			regards, tom lane
> 

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