Re: Re: Density statistic calculation in case of histogram

  • From: "Alberto Dell'Era" <alberto.dellera@xxxxxxxxx>
  • To: neeraj.dba@xxxxxxxxx
  • Date: Thu, 9 Apr 2009 00:14:31 +0200

On Mon, Apr 6, 2009 at 17:20, Neeraj Bhatia <neeraj.dba@xxxxxxxxx> wrote:
> Basically I am interested to know how density is calculated in case of
> height-based histograms. Also, how CBO calculate selectivity.

I wouldn't investigate too much the density in 10.x since the formula
has changed (to a very intuitive one) in 11gR1:

so, the 10.x formula has been "deprecated" by the kernel developers.

I did find a statistical justification for the 10.x computation, but
I have never "published" it for the above reasons, it is no longer


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