Re: An Idea for planner hints

Ühel kenal päeval, E, 2006-08-14 kell 18:21, kirjutas Peter Eisentraut:
> Perez wrote:
> > I thought, from watching the list for a while, that the planner
> > statistics needed were known but that how to gather the statistics
> > was not?
> 
> I think over the course of the discussion we have figured out that we 
> would like to have cross-column correlation statistics.  The precise 
> mathematical incarnation hasn't been determined yet, as far as I can 
> see.  Collecting the statistics thereafter isn't that hard, but there 
> needs to be a way to not collect an exponential volume of statistics on 
> all column combinations.

I understood that the proposal was to collect only the stats where
needed (determined by user/dba) and use some rule-of-thumb values if no
collected stats were available.

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