Thread: Re: partitioned table and ORDER BY indexed_field DESCLIMIT 1
Works great - plans no longer sort, but rather use indices as expected. It's in use in Greenplum now.
It's a simple approach, should easily extend from gpdb to postgres. The patch is against gpdb so someone needs to 'port' it.
- Luke
Msg is shrt cuz m on ma treo
-----Original Message-----
From: Simon Riggs [mailto:simon@2ndquadrant.com]
Sent: Saturday, October 27, 2007 05:34 PM Eastern Standard Time
To: Luke Lonergan
Cc: Heikki Linnakangas; Anton; pgsql-performance@postgresql.org
Subject: Re: [PERFORM] partitioned table and ORDER BY indexed_field DESCLIMIT 1
On Sat, 2007-10-27 at 15:12 -0400, Luke Lonergan wrote:
> And I repeat - 'we fixed that and submitted a patch' - you can find it
> in the unapplied patches queue.
I got the impression it was a suggestion rather than a tested patch,
forgive me if that was wrong.
Did the patch work? Do you have timings/different plan?
--
Simon Riggs
2ndQuadrant http://www.2ndQuadrant.com
On Sat, 2007-10-27 at 17:48 -0400, Luke Lonergan wrote: > Works great - plans no longer sort, but rather use indices as > expected. It's in use in Greenplum now. > > It's a simple approach, should easily extend from gpdb to postgres. > The patch is against gpdb so someone needs to 'port' it. The part of the patch that didn't work for me was the nrels==1 bit. The way it currently works there is only ever 0 or 2+ rels. The normal Postgres code has to cater for the possibility of a non-empty parent table, which seems to destroy the possibility of using this technique. I agree its annoying and I have a way of doing this, but that's an 8.4 thing now. Anybody think different? -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com
Simon Riggs <simon@2ndquadrant.com> writes:
> I agree its annoying and I have a way of doing this, but that's an 8.4
> thing now.
It was an 8.4 thing quite some time ago, since no working patch was ever
submitted.
regards, tom lane
On Sun, 2007-10-28 at 12:53 -0400, Tom Lane wrote: > Simon Riggs <simon@2ndquadrant.com> writes: > > I agree its annoying and I have a way of doing this, but that's an 8.4 > > thing now. > > It was an 8.4 thing quite some time ago, since no working patch was ever > submitted. Sorry, I meant that the problem itself is annoying, not anything to do with patches. I'm very happy with all that we've done. -- Simon Riggs 2ndQuadrant http://www.2ndQuadrant.com