[postgis-devel] Re: geometry stats

[strk]

Ok. I'm at a good point (I hope).
All the code is in those 3 monolithic functions:
	geometry_analyze()
	compute_geometry_stats()
	postgis_gist_sel()  <-- warning, there are two of these.. 

The new postgis_gist_sel() seems now able to get to the stats,
at least in the simple cases the_geom && 'box', 'box && the_geom.
I please anyone to test more complex cases: NOTICEs should arise
when problems are encountered.

I have lots of questions opened:

	1) should we consider the null fraction when making the
	   estimation or is it something postgresql will handle itself ?

	2) should we handle the const && const case evaluating it
	   and returning either 1 when true or (what?) when false ?

	3) is there a test suite to help tuning the estimator ?
	   [ this is for Dave ]

	4) why does the returned estimate change the result of a query ?
	   [ box_contained() bug ? ]

	5) how do we compose the bits we have: cell_area, box_area, AOI,
	   cell_value, avgFeaturesArea to get a nice picture ;) ?

	5bis) how do we see the nice picture ? (see point 3)

The code has been committed. It's highly experimental, but should not
conflict with builds other then against PG75 (CVS).

Thanks for your attention.

--strk;