Re: index selectivity when histograms presents on the column
- From: "Jared Still" <jkstill@xxxxxxxxx>
- To: sjaffarhussain@xxxxxxxxx
- Date: Mon, 27 Mar 2006 11:50:51 -0800
The explanation is found in Jonathan Lewis' CBO book:
http://www.amazon.com/gp/product/1590596366
There is a rather extensive chapter on histgrams, and it
does cover selectivity.
Jared
On 3/21/06, The Human Fly <sjaffarhussain@xxxxxxxxx> wrote:
>
> List,
>
> Can anyone tell me the index selectivity formula for a column when
> there are histograms on the column.
> I know that the index selectivity without histograms is =
> num_distinct/num_rows and also know that table selectivity uses
> density to calculate the selectivty when there are histograms placed
> on the column.
>
> Thanks,
> --
> Best Regards,
> Syed Jaffar Hussain
> 8i,9i & 10g, OCP DBA
> Banque Saudi Fransi,
> Saudi Arabia
> http://jaffardba.blogspot.com/
>
> ----------------------------------------------------------------------------------
> "Winners don't do different things. They do things differently."
> --
> //www.freelists.org/webpage/oracle-l
>
>
>
--
Jared Still
Certifiable Oracle DBA and Part Time Perl Evangelist
Other related posts:
