Re: Difference between build index and gather stat

Jaap W. van Dijk wrote:

> ... if you have an enabled
> primary key, Oracle will keep an index on the column or columns on
> which you defined the key, and will keep this up to date when using
> DML. So yes, you can expect Oracle to use your index again.
>
> Jaap.

Had I not just spent 3 days taking Jonathan Lewis' Optimizing Oracle seminar I'd have agreed ... but now I hedge on giving this advice.

Oracle will, of course, keep the index up-to-date. But changes in statistics, changes in data, changes in lots of places could cause the optimizer to make different choices.

-- 
Daniel A. Morgan
http://www.psoug.org
damorgan_at_x.washington.edu
(replace x with u to respond)