From: Steinar H. Gunderson <sgunderson@bigfoot.com>
To: Pepe Barbe <elventear@gmail.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Join performance
Date: Thu, 8 Nov 2007 23:51:20 +0100
Message-ID: <20071108225120.GA22963@uio.no> (raw)
In-Reply-To: <2ACEBABD-7853-475B-B8C0-91B654AF143D@gmail.com>
References: <2ACEBABD-7853-475B-B8C0-91B654AF143D@gmail.com>
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 */
--
Homepage: http://www.sesse.net/
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To: pgsql-performance@postgresql.org
Cc: sgunderson@bigfoot.com, elventear@gmail.com
Subject: Re: Join performance
In-Reply-To: <20071108225120.GA22963@uio.no>
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