From: | "Jim C(dot) Nasby" <jnasby(at)pervasive(dot)com> |
---|---|
To: | "Jeffrey W(dot) Baker" <jwbaker(at)acm(dot)org> |
Cc: | pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Configuration WAS: New project launched : PostgreSQL |
Date: | 2006-01-31 23:17:04 |
Message-ID: | 20060131231704.GQ95850@pervasive.com |
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Thread: | |
Lists: | pgsql-hackers |
On Tue, Jan 31, 2006 at 03:11:50PM -0800, Jeffrey W. Baker wrote:
> On Tue, 2006-01-31 at 17:06 -0600, Jim C. Nasby wrote:
> > On Tue, Jan 31, 2006 at 12:36:31PM -0800, Jeffrey W. Baker wrote:
> > > Random page cost - should possible to determine this at runtime
> >
> > Before worrying about random_page_cost at all it makes a lot more sense
> > to look at the query cost estimates, some of which are pretty far out of
> > wack.
>
> I agree, but this problem is orthogonal, no?
No. The problem is that random_page_cost has the wrong effect in some of
the cost functions, so even if you set it more accurately you're not
buying anything. In fact, you might well be hurting performance.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461
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