Skip site navigation (1) Skip section navigation (2)

Re: Query Planner

From: "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com>
To: Gauri Kanekar <meetgaurikanekar(at)gmail(dot)com>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: Query Planner
Date: 2007-02-26 11:52:27
Message-ID: 20070226115227.GA4338@uio.no (view raw or flat)
Thread:
Lists: pgsql-performance
On Mon, Feb 26, 2007 at 05:19:05PM +0530, Gauri Kanekar wrote:
> I have a Query. So when i do explain analyse on it , it shows me many Hash
> Joins.
> So is it possible to indicate the Query Planner not to consider Hash Join.

set enable_hashjoin = false;

This is very often the wrong solution, though. If hash join is indeed slower
than merge join, the planner should have guessed so, and it would be better
to find out why the planner guessed wrong, and correct it somehow.

/* Steinar */
-- 
Homepage: http://www.sesse.net/

In response to

pgsql-performance by date

Next:From: Guillaume SmetDate: 2007-02-26 12:42:40
Subject: Re: pg_trgm performance
Previous:From: Gauri KanekarDate: 2007-02-26 11:49:05
Subject: Query Planner

Privacy Policy | About PostgreSQL
Copyright © 1996-2014 The PostgreSQL Global Development Group