Re: Posible planner improvement?

From: "Kevin Grittner" <Kevin(dot)Grittner(at)wicourts(dot)gov>
To: "ITAGAKI Takahiro" <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, "Albert Cervera Areny" <albert(at)sedifa(dot)com>
Cc: <pgsql-performance(at)postgresql(dot)org>
Subject: Re: Posible planner improvement?
Date: 2008-08-04 18:16:45
Message-ID: 4897013D.EE98.0025.0@wicourts.gov
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

>>> On Mon, May 26, 2008 at 6:30 AM, ITAGAKI Takahiro
<itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp> wrote:
> Albert Cervera Areny <albert(at)sedifa(dot)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

In response to

Browse pgsql-performance by date

  From Date Subject
Next Message Mark Wong 2008-08-05 04:54:36 file system and raid performance
Previous Message H. Hall 2008-08-04 11:20:45 Re: SSD Performance Article