Re: Dbms_stats Analyze Data Dictionay ?

All,

Did not mean to imply that the RBO was kaput in 9i, just that they are phasing it out.

Even in 10i I would certainly test the DD analyze thoroughly before I relied on it.

Jack

depifster_at_yahoo.com (Jack Silvey) wrote in message news:<25c7944d.0305251049.4b6064fc_at_posting.google.com>...
> Ryan,
>
> Without stats on the DD, your recursive data dictionary queries run
> under rule based optimization, which is the intent in earlier versions
> of Oracle (<9i).
>
> If you analyze the DD, the optimizer will try to use cost based
> optimization in dictionary queries. This can be a disaster since the
> dictionary was designed long ago to run under rule. The CBO could
> start making very bad choices about execution plans and this can
> really slow down all your users (sort segment allocation, query
> parsing, space allocation, stats gathering, etc.)
>
> A good thing might be to test on your dev/qa systems.
>
> hth,
>
> Jack Silvey
> warehouse DBA somewhere in Texas
>
>
>
> > acceptable? does it help at all or its just not a bad thing?
Received on Mon May 26 2003 - 18:27:49 CDT