[postgis-users] Histogram2d formation

[David Blasby]

The results for the "bigger" bounding boxes are in.

150,000 boxes were made with side between 10k and 500km. 95,985 of these boxes
actually hit features (avg of 5324/box).

The average error for the 150,000 boxes was 257, and the avg error not including the
zero-error estimates was 392.  The largest error was 31,555 (actual was 66,162).

%99 of errors were <6,955  95% were < 1,355 and 90% were < 691

I have the new histogram estimator working on my system - unfortunately the postgresql
index-cost-computer is incorrectly estimating the cost of  the GiST index vs
sequential scanning.

I'm looking into it now, but its pretty deep mojo!

dave