# Re: Re: Density statistic calculation in case of histogram

Date: Thu, 9 Apr 2009 06:49:44 +0530

Message-ID: <a8fd4d730904081819w23d6b1as2200f8639902fa33_at_mail.gmail.com>

Thanks Alberto for the update. Actually I am investigating the calculations in R10 and my plan was to later cover R11 as well. Since still most of the systems are on R10 and in future also (atleast 2-3 years), I am very interested.

Having said that, your references and update will be very helpful. I just downloaded the stuff and reading :-)

On Thu, Apr 9, 2009 at 3:44 AM, Alberto Dell'Era <alberto.dellera_at_gmail.com>wrote:

*> On Mon, Apr 6, 2009 at 17:20, Neeraj Bhatia <neeraj.dba_at_gmail.com> 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:*

*>*

*> http://www.adellera.it/investigations/11g_newdensity/index.html*

*>*

*> 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*

*> important.*

*>*

*> hth*

*> alberto*

*>*

-- http://www.freelists.org/webpage/oracle-lReceived on Wed Apr 08 2009 - 20:19:44 CDT