From: Kevin Grittner <Kevin.Grittner@wicourts.gov>
To: ITAGAKI Takahiro <itagaki.takahiro@oss.ntt.co.jp>
To: Albert Cervera Areny <albert@sedifa.com>
Cc: pgsql-performance@postgresql.org
Subject: Re: Posible planner improvement?
Date: Mon, 04 Aug 2008 13:16:45 -0500
Message-ID: <4897013D.EE98.0025.0@wicourts.gov> (raw)
In-Reply-To: <20080526201825.C96D.52131E4D@oss.ntt.co.jp>
References: <200805211228.48248.albert@sedifa.com>
<20080526201825.C96D.52131E4D@oss.ntt.co.jp>
>>> On Mon, May 26, 2008 at 6:30 AM, ITAGAKI Takahiro
<itagaki.takahiro@oss.ntt.co.jp> wrote:
> Albert Cervera Areny <albert@sedifa.com> 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;
>
> I had a similar problem here:
> http://archives.postgresql.org/pgsql-general/2007-02/msg00850.php
> and added a redundant inequality explicitly to make it work well.
>
> I think it is worth trying to improve, but I'm not sure we can do it
> against user defined types. Does postgres always require transitive
law
> to all types?
I've recently run into this. It would be a nice optimization,
if feasible.
-Kevin
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To: pgsql-performance@postgresql.org
Cc: Kevin.Grittner@wicourts.gov, itagaki.takahiro@oss.ntt.co.jp, albert@sedifa.com
Subject: Re: Posible planner improvement?
In-Reply-To: <4897013D.EE98.0025.0@wicourts.gov>
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