Re: An Idea for planner hints

On Wed, Aug 09, 2006 at 08:31:42AM -0400, Perez wrote:
> Every once in a while people talk about collecting better statistics,
> correlating multi-column correlations etc. But there never seems to be
> a way to collect that data/statistics.
>
> Would it be possible to determine the additional statistics the planner
> needs, modify the statistics table to have them and document how to
> insert data there? We wouldn't have a good automated way to determine
> the information but a properly educated DBA could tweak things until
> they are satisfied.
>
> At worse if this new information is unpopulated then things would be as
> they are now. But if a human can insert the right information then some
> control over the planner would be possible.
>
> Is this a viable idea? Would this satisfy those that need to control
> the planner immediately without code changes?

Sure, it's a Simple Matter of Code.

The real issue is figuring out what to do with these stats. I think all
the estimator fucntions could use improvement, but no one's taken that
on yet.
--
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