Re: Please Help: Sudden Drop in SQL Performance

Harald

If OPTIMIZER_MODE=rule, and Oracle uses the statistics, it's either because of a specific hint, or a bug. Default behaviour is as you understand.

HTH. Pete

Harald Wakonig wrote:

> Hi Jack,
>
> > 3) Check if any of your tables/indexes have statistics. This will cause
> > weird performance - even in rule based....if they are there Oracle uses
> > them!
>
> Oracle uses statistics even if rule based ? I understand that behaviour if
> optimizer mode = choose - that is documented, but if optimizer mode = RULE ????
>
> Is this
>
> (1) just a rumor
> (2) a documented feature (where ? which Oracle-manual ?)
> (3) a bug - (Bug-Nr. please) - generic or platform / release-specific ?
>
> Thanks,
>
> Harald

Received on Mon Jan 10 2000 - 11:25:42 CST