Re: An ancient mystery

Is partitioning or another feature that implies the cost based optimiser in use?

On 11/21/08, Dennis Williams <oracledba.williams_at_gmail.com> wrote:
> List,
>
> The situation:
>
> Oracle 8.1.7.4 database on Solaris 8 (soon to be upgraded to 10g)
> Rule-based Optimizer
>
> A query which has run for years using an indexed access to a very large
> table (maybe 100 million rows)
> suddenly decides to use a full-table scan, shutting down a critical business
> process.
>
> Then after several hours, it switches back to using the index.
> All concerned claim that nothing changed before or after.
>
> Needless to say the business users are nervous. They think maybe the
> database grew beyond some limit.
>
> Can anyone think of an explanation?
>
> Thanks,
> Dennis Williams
>

-- 
Sent from Google Mail for mobile | mobile.google.com

Niall Litchfield
Oracle DBA
http://www.orawin.info
--
http://www.freelists.org/webpage/oracle-l