Re: Statistics and optimizer

From: Ann Myhre <annmyhre_at_hotmail.com>
Date: Tue, 08 May 2001 05:49:32 GMT
Message-ID: <MNLJ6.6587$Sq.643100@juliett.dax.net>

"Ricky Sanchez" <rsanchez_at_more.net> wrote in message news:3AF74243.B4ECA8AA_at_more.net...
> Actually, a simple way of looking at it is that if *any* hint is used,
> other than "rule", then CBO will be used. If CBO is used for any part of
> the query, ie subqueries, then the entire statement will use CBO.
>
> - ricky

That really confuse me. What you say is that, if I use any hints exept RULE, and even though I haven't collected ANY statistics (there is absolutely NO statistics genererated an any object whatsoever), Oracle (optimizer) will choose CBO?
My problem is that I want of course in most cases optimizer to choose CBO, but from the information I have got it seems that it will choose RBO if I haven't rembered to use ANALYZE first. I have tried different approches and from the EXPLAIN PLAN it also seems to choose CBO even though I have not used ANALYZE. But maybe I read something wrong?

Ann Received on Tue May 08 2001 - 00:49:32 CDT