Re: How hints affect the CBO?

In article <afeqck$q57$1_at_babylon.agtel.net>, you said (and I quote):
>
> So, how does CBO work with respect to hints? Does it treat them as
> direct orders if they specify valid access path and does not consider
> alternatives,

AFAIK, this is pretty much the case. At least pre-9i. Dunno if this one changes the hint behaviour.

> or does it just tweak costs so that the hinted path looks
> better than the others, but still can choose a different path?

IIRC, the only instance where this may happen is with parallel processing/parallel query. But I'll duly stand corrected if that isn't the case.

> Anyone
> seen/can provide an example of CBO choosing path different from
> one suggested by a valid hint that does not exhibit a bug in CBO?

Nope. However, that's not to say I haven't seen bugs in the CBO...

-- 
Cheers
Nuno Souto
nsouto_at_optushome.com.au.nospam