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List:       postgresql-general
Subject:    Re: [HACKERS] limit in subquery causes poor selectivity estimation
From:       Tom Lane <tgl () sss ! pgh ! pa ! us>
Date:       2011-08-31 18:12:58
Message-ID: 21748.1314814378 () sss ! pgh ! pa ! us
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Robert Haas <robertmhaas@gmail.com> writes:
> On Wed, Aug 31, 2011 at 6:22 AM, Peter Eisentraut <peter_e@gmx.net> wrote:
>> I liked the old one better. ;-)

> AFAICS, those plans are identical, except for a minor difference in
> the cost of scanning test2.

The point is that the estimate of the result size is worse in 8.4.8.

I am not, however, convinced that 8.4.7 was actually smarter ... it
may have been getting the right answer for the wrong reason.

			regards, tom lane

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