Message-ID: <4833FDE5.8090603@archonet.com>
Date: Wed, 21 May 2008 11:48:05 +0100
From: Richard Huxton <dev@archonet.com>
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To: Albert Cervera Areny <albert@sedifa.com>
CC: pgsql-performance@postgresql.org
Subject: Re: Posible planner improvement?
References: <200805211228.48248.albert@sedifa.com>
In-Reply-To: <200805211228.48248.albert@sedifa.com>
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Albert Cervera Areny wrote:
> I've got a query similar to this:
> 
> select * from t1, t2 where t1.id > 158507 and t1.id = t2.id;
> 
> That took > 84 minutes (the query was a bit longer but this is the part that 
> made the difference) after a little change the query took ~1 second:
> 
> select * from t1, t2 where t1.id > 158507 and t2.id > 158507 and t1.id = 
> t2.id;

Try posting EXPLAIN ANALYSE SELECT ... for both of those queries and 
we'll see why it's better at the second one.

-- 
   Richard Huxton
   Archonet Ltd