Re: performance drop on 8.2.4, reverting to 8.1.4

From: "Steinar H(dot) Gunderson" <sgunderson(at)bigfoot(dot)com>
To: Liviu Ionescu <ilgb(at)livius(dot)net>
Cc: pgsql-performance(at)postgresql(dot)org
Subject: Re: performance drop on 8.2.4, reverting to 8.1.4
Date: 2007-05-18 09:49:21
Message-ID: 20070518094921.GA13598@uio.no
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On Fri, May 18, 2007 at 12:02:44PM +0300, Liviu Ionescu wrote:
> the 8.2.4 plan with join_collapse_limit = 1 (with default it was worse, full of nested loops)

It will probably be useful with EXPLAIN ANALYZE of your queries, not just the
EXPLAIN.

> "Nested Loop Left Join (cost=32.01..2012.31 rows=1 width=230)"

It looks like the planner thinks this is going to be really cheap -- so it's
misestimating something somewhere. Have you ANALYZEd recently?

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

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