Re: Thoughts on statistics for continuously advancing columns

On Thu, 2009-12-31 at 21:29 +0000, Simon Riggs wrote:
> On Thu, 2009-12-31 at 15:18 -0500, Tom Lane wrote:
> > Simon Riggs <simon@2ndQuadrant.com> writes:
> > > Why not get both max() and min(), then rebase the histogram according to
> > > those values. That way the histogram can still move significantly and
> > > the technique will still work.
> > 
> > Define "rebase", keeping in mind that this has to work on datatypes that
> > we don't have a distance metric for.
> 
> Make it work differently according to whether we have, or not, just as
> we do elsewhere with stats. No point in limiting ourselves to the lowest
> common denominator, especially when the common case is integer keys and
> time datatypes.

This seemed obvious but I understand now that you meant we don't know
that from the datatype definition, so we can't do as I suggested, yet.

-- Simon Riggs           www.2ndQuadrant.com