Re: CBO / RBO question

Hi Russ,

I think Oracle will use the CBO because of DOP > 1 (as well as partitioning) forces using the CBO. You can always check what optimizer is used by Oracle via column COST in the explain plan.

Regards
Ed

> Hi all,
> On Oracle 8.0.5 CBO, we encountered an issue with the CBO choosing to
> access a table via an index read instead of by ROWID. By dropping
> statistics on the table, we triggered it to use RBO and corrected the
> problem. Here's the question. If we increase the degree of parallel,
this
> would normally cause the CBO to be used. But since the statistics are
still
> gone, don't we wind back up using the RBO?
>
> Thanks,
> Russ
> --
> Please see the official ORACLE-L FAQ: http://www.orafaq.com
> --
> Author: Russell Brooks
> INET: russell.brooks_at_amctechnology.com
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Received on Mon Dec 11 2000 - 03:33:14 CST