Oracle FAQ | Your Portal to the Oracle Knowledge Grid |
Home -> Community -> Usenet -> c.d.o.server -> Re: How hints affect the CBO?
I was thinking some more about this, and this makes sense. The purpose of
hints is to enable the optimiser to choose a *different* path to the one
that it calculates as best. The behaviour that you originally postulated
would probably make people swear at the optimiser even more than they
currently do.
-- Niall Litchfield Oracle DBA Audit Commission UK ***************************************** Please include version and platform and SQL where applicable It makes life easier and increases the likelihood of a good answer ****************************************** "Vladimir M. Zakharychev" <bob_at_dpsp-yes.com> wrote in message news:aff0kg$s6h$1_at_babylon.agtel.net...Received on Thu Jun 27 2002 - 08:33:54 CDT
> Ok, MetaLink note 69992.1 explicitly states that
> "Correctly defined hints are DIRECTIVES to the optimizer to use a
particular
> access method or access type. They should not be ignored and should be
> obeyed at all times by the optimizer."
>
> So my assumptions about CBO were incorrect after all.
>
> --
> Vladimir Zakharychev (bob_at_dpsp-yes.com)
http://www.dpsp-yes.com
> Dynamic PSP(tm) - the first true RAD toolkit for Oracle-based internet
applications.
> All opinions are mine and do not necessarily go in line with those of my
employer.
>
>