Postgres Pro
Downloads
Home   >   mailing lists

Re: postgresql uses Hash-join, i need Nested-loop - Mailing list pgsql-performance

From Tom Lane
Subject Re: postgresql uses Hash-join, i need Nested-loop
Date
Msg-id 11393.1251124624@sss.pgh.pa.us
Whole thread Raw
In response to postgresql uses Hash-join, i need Nested-loop  (Gábor Farkas <gabor@nekomancer.net>)
List pgsql-performance
Tree view 
=?ISO-8859-1?Q?G=E1bor_Farkas?= <gabor@nekomancer.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

pgsql-performance by date:

Previous
From: "Kevin Grittner"
Date:
Subject: Re: Number of tables
Next
From: "Kevin Grittner"
Date:
Subject: Re: improving my query plan