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From: Mladen Gogala <mladen.gogala@vmsinfo.com>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Achilleas Mantzios <achill@matrix.gatewaynet.com>
Cc: pgsql-performance@postgresql.org <pgsql-performance@postgresql.org>
Subject: Re: "NOT IN" substantially slower in 9.0.2 than 8.3.13 - NOT EXISTS runs fast in both 8.3.13 and 9.0.2
Date: Fri, 21 Jan 2011 12:42:37 -0500
Message-ID: <4D39C58D.4060709@vmsinfo.com> (raw)
In-Reply-To: <AANLkTimeC41oJ34yzPPf3wc_qQ_mKT_=krCcD7OMEYsc@mail.gmail.com>
References: <955263366.48014741295283147090.JavaMail.root@ucimail4.uci.cu>
	<201101191110.05268.achill@matrix.gatewaynet.com>
	<21792.1295458016@sss.pgh.pa.us>
	<201101200905.26400.achill@matrix.gatewaynet.com>
	<AANLkTimeC41oJ34yzPPf3wc_qQ_mKT_=krCcD7OMEYsc@mail.gmail.com>

On 1/21/2011 12:09 PM, Robert Haas wrote:
> Looks like the bad selectivity estimate there is what's killing it.
> Not sure I completely understand why 9.0.2 is coming up with such a
> bad estimate, though.
>

I would recommend setting default_statistics_target to 1024 and 
effective cache size to 20480MB and see what happens.

-- 

Mladen Gogala
Sr. Oracle DBA
1500 Broadway
New York, NY 10036
(212) 329-5251
http://www.vmsinfo.com
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