Re: Performance / Index

From: Terry Ball <terry_ball_at_csgsystems.com>
Date: 2000/04/13
Message-ID: <38F60B78.157353A4@csgsystems.com>#1/1

Nuno Souto wrote:

> On Wed, 12 Apr 2000 17:26:54 +0100, Duarte Nuno Sousa
> <Duarte.Sousa_at_solsuni.pt> wrote:
>
> >I have already re-analyzed the tables and the indexes, but with the estimate
> >statistics, or should i use the compute statistics ?
>
> Hmm, I use compute evey time I can. But you might get away with
> estimate. Use a reasonable percentage, not 10%. Something like 50.
>

If you use a percentage of 50, oracle will automatically do a compute so if you are going to use 50%, you might just as well compute.

Mike Ault (who presents at IOUG and other places, and works for RevealNet) says he did extensive testing on this. He has proven to his satisfaction, that a sample of 30% is best. It gives more that adequate numbers with the least time. A smaller percentage does not give as close results and a higher percentage does not give any more accurate figurs while taking longer.

Terry Received on Thu Apr 13 2000 - 00:00:00 CDT