Re: Query optimizer 8.0.1 (and 8.0) - Mailing list pgsql-hackers

From Bruce Momjian
Subject Re: Query optimizer 8.0.1 (and 8.0)
Date
Msg-id 200502201936.j1KJahU15443@candle.pha.pa.us
Whole thread Raw
In response to Re: Query optimizer 8.0.1 (and 8.0)  ("Jim C. Nasby" <decibel@decibel.org>)
Responses Re: Query optimizer 8.0.1 (and 8.0)
Re: Query optimizer 8.0.1 (and 8.0)
List pgsql-hackers
Jim C. Nasby wrote:
> On Mon, Feb 14, 2005 at 09:55:38AM -0800, Ron Mayer wrote:
>  
> > I still suspect that the correct way to do it would not be
> > to use the single "correlation", but 2 stats - one for estimating
> > how sequential/random accesses would be; and one for estimating
> > the number of pages that would be hit.  I think the existing
> > correlation does well for the first estimate; but for many data
> > sets, poorly for the second type.
>  
> Should this be made a TODO? Is there some way we can estimate how much
> this would help without actually building it?

I guess I am confused how we would actually do that or if it is
possible.

--  Bruce Momjian                        |  http://candle.pha.pa.us pgman@candle.pha.pa.us               |  (610)
359-1001+  If your life is a hard drive,     |  13 Roberts Road +  Christ can be your backup.        |  Newtown Square,
Pennsylvania19073
 


pgsql-hackers by date:

Previous
From: "Magnus Hagander"
Date:
Subject: Re: win32 performance - fsync question
Next
From: Mark Kirkwood
Date:
Subject: Re: Data loss, vacuum, transaction wrap-around