Re: Interpreting cost on EXPLAIN PLAN

Jonathan Lewis wrote:
> The error is in the reporting of the index cost.
> If you check lots of plans, you will find that
> there are several cases where some number
> is wrong, even though the correct number is
> actually used elsewhere - even to the extent
> that the 10053 trace shows one number, but
> the execution plan prints another.

Thank you.

> The draft of the book is not on the web.
>
> I hadn't realised that anyone had written
> a book about the cost based optimizer,
> although Dan Tow has written a very
> interesting book about tuning SQL, and
> a couple of other people have done some
> pretty good stuff about tuning SQL in the
> past.

Kim Floss had written _Oracle SQL Tuning & CBO Internals_ which is a collection of articles by various authors. Some of it does cover CBO internals, but not in depth.

> --
> Regards
>
> Jonathan Lewis
>
> Now waiting on the publishers: Cost Based Oracle - Volume 1
>
> http://www.jlcomp.demon.co.uk/faq/ind_faq.html
> The Co-operative Oracle Users' FAQ
>
> http://www.jlcomp.demon.co.uk/appearances.html
> Public Appearances - schedule updated 8th July 2005
Received on Wed Aug 17 2005 - 14:49:55 CDT