Re: postgresql uses Hash-join, i need Nested-loop

From: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
To: Gábor Farkas <gabor(at)nekomancer(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: postgresql uses Hash-join, i need Nested-loop
Date: 2009-08-24 14:37:04
Message-ID: 11393.1251124624@sss.pgh.pa.us
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=?ISO-8859-1?Q?G=E1bor_Farkas?= <gabor(at)nekomancer(dot)net> writes:
> i have a query that uses a Hash-Join, but it would be faster with Nested-Loop,
> and i don't know how to persuade postgresql to do it.

Fix the way-off-base rowcount estimates ...

> postgresql-8.2 + tsearch2

... which is just about impossible in 8.2, because there's no
statistical support for @@ selectivity estimation. Consider
updating to 8.4.

regards, tom lane

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