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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 13:12:55 -0500
Message-ID: <4D39CCA7.1040507@vmsinfo.com> (raw)
In-Reply-To: <AANLkTi=QzQXtLYkdatf1ginDXyJ=c-bOYhPKT766KB+u@mail.gmail.com>
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	<AANLkTimeC41oJ34yzPPf3wc_qQ_mKT_=krCcD7OMEYsc@mail.gmail.com>
	<4D39C58D.4060709@vmsinfo.com>
	<AANLkTi=QzQXtLYkdatf1ginDXyJ=c-bOYhPKT766KB+u@mail.gmail.com>

On 1/21/2011 12:51 PM, Robert Haas wrote:
> I am starting to suspect that there is a bug in the join selectivity
> logic in 9.0.  We've had a few complaints where the join was projected
> to return more rows than the product of the inner side and outer side
> of the join, which is clearly nonsense.  I read the function and I
> don't see anything weird... and it clearly can't be too bad or we
> would have had more complaints... but...

Well the way to test it would be to take the function from 8.3, input 
the same arguments and see if there is any difference with the results.

-- 

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