| From: | "Jim C(dot) Nasby" <decibel(at)decibel(dot)org> |
|---|---|
| To: | Ron Mayer <rm_pg(at)cheapcomplexdevices(dot)com> |
| Cc: | pgsql(at)mohawksoft(dot)com, Oleg Bartunov <oleg(at)sai(dot)msu(dot)su>, Mark Kirkwood <markir(at)coretech(dot)co(dot)nz>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, pgsql-hackers(at)postgresql(dot)org |
| Subject: | Re: Query optimizer 8.0.1 (and 8.0) |
| Date: | 2005-02-16 02:00:00 |
| Message-ID: | 20050216020000.GQ52357@decibel.org |
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| Lists: | pgsql-hackers |
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?
--
Jim C. Nasby, Database Consultant decibel(at)decibel(dot)org
Give your computer some brain candy! www.distributed.net Team #1828
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