Date: Thu, 8 Nov 2007 23:51:20 +0100
From: "Steinar H. Gunderson" <sgunderson@bigfoot.com>
To: Pepe Barbe <elventear@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Join performance
Message-ID: <20071108225120.GA22963@uio.no>
Mail-Followup-To: Pepe Barbe <elventear@gmail.com>,
	pgsql-performance@postgresql.org
References: <2ACEBABD-7853-475B-B8C0-91B654AF143D@gmail.com>
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On Thu, Nov 08, 2007 at 04:47:09PM -0600, Pepe Barbe wrote:
> I am having an issue on PostgreSQL 8.0.12. In the past we had performance 
> issues with the query planner for queries on some tables where we knew we 
> had indexes and it was doing a sequential scan, and for this reason we 
> issue "SET enable_seqscan = FALSE" for some queries.

This is a bad idea in general. Did you really measure that this made queries
run faster? Generally, using an index is not always a win, and the planner
tries to figure out when it isn't. Setting it globally is seldom a good idea
anyway; if it really _is_ a win for a given query, you could always set it
locally in that session.

> Any ideas what could I try to fix this problem?

Re-enable seqscan?

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