Re: Need Help With SQL Statement Please

In article <4mnmah$ptn_at_maddawg.sii.com>, David J Roth <droth_at_adaptron.com> wrote:

> "James A. Mumper" <jamumper_at_mercury.ptes.com> wrote:
> >
> > Charlie Peck wrote:
> > >
> > > In article <4m85du$t18_at_newshost.ptes.com>, jamumper_at_ptes.com wrote:
> > >
> > > > In Loney's DBA book and the Oracle DBA book is a script which allows you
> > > to use existing
 snip
> > --
> > James A. Mumper
> > Senior Oracle DBA
> > Pacific Telesis Video Services
>
> Beware of side effects!
>
> The analyze command produces statistics that are used by
> the cost based optimizer. If the statistics are not present
> for any table involved in a statement the rule based optimizer
> is used. If the statistics are present for some of the tables
> the cost based optimizer is used. In this mixed situation the
> cost based optimizer does not have all of the information that
> it needs and is not likely to do the best possible job.

Doesn't "optimizer_mode = rule" prevent this from happening? My understanding is that even if _all_ the tables had stats present than rule would still be used.

charlie Received on Wed May 08 1996 - 00:00:00 CEST