>On Behalf Of
Nigel Thomas
>To be fair, the sentence
continues (my bold, from 10gR1):
>"...a full table scan
might be cheaper than an index range scan"
>or by implication it might not. Or they
could be the same. Or England could win the World Cup. Or whatever. Looks like
they've got all the angles covered there then.
And surely I am lost. What are the
best practices for SQL programmer in the modern
post_Rule_Based_Optimizer Oracle then?
- Rely on unreliable CBO? But all
we have already heard stories of even Oracle fighting it's own CBO for *stable*
data dictionary performance. And CBO is inherently unstable at least in the
beginning of application's life cycle.
- Onlines? But they may or may not
to cover all SQL. And outlines will not cover literal SQL("legal" literal SQL),
will they?
- Hint every single statement? That
one seems to be the option, doesn't it?
P.S. Just wandering: is there a
hint to *disable* statistics at statement or session level? I mean, let CBO use
*defaults* making it kind of rule based actually.
Thank you in
advance,
Laimis
N.
