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Re: Bogus nestloop join estimate, ignores WHERE clause

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 join estimate, ignores WHERE clause
Date: 2011-08-31 20:59:19
Message-ID: 3645.1314824359@sss.pgh.pa.us (view raw or flat)
Thread:
Lists: pgsql-hackers
Marti Raudsepp <marti(at)juffo(dot)org> writes:
> After a bit of digging, I figured out that it uses the same estimate
> as a semi-join WITHOUT the client_id restriction.
> ...
> For whatever reason, the 1st query completely ignores the fact that
> the client_id clause reduces the result count by a large factor.

Could we see the pg_stats rows for the two join columns?

			regards, tom lane

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