Re: Bogus nestloop rows estimate in 8.4.7

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Marti Raudsepp <marti(at)juffo(dot)org>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Bogus nestloop rows estimate in 8.4.7
Date: 2012-05-28 17:56:55
Message-ID: 9486.1338227815@sss.pgh.pa.us
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Marti Raudsepp <marti(at)juffo(dot)org> writes:
> This bug isn't causing me any immediate problems -- the plan works out
> well regardless -- but PostgreSQL 8.4.7 is somehow overestimating the
> number of rows coming from a nestloop join, when joining 2 large
> partitioned tables.

This sounds familiar, but a quick trawl through the commit logs didn't
immediately turn up any related-looking patches. Can you put together
a self-contained test case?

Also, what do you have constraint_exclusion set to?

regards, tom lane

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