Re: max_estimated_exec_time

"David COSTE" <david.coste_at_norep.hp.com> wrote in message news:ccFBb.10435$9H6.5234_at_news.cpqcorp.net...
> Hello,
>
> I have a question relative to Oracle 9.2.0.
> The resource manager includes a directive MAX_ESTIMATED_EXEC_TIME which is
> valued in seconds.
> According to me just specifying this directive is enough to prevent a
query
> from running if the CBO estimates a duration greater then
> MAX_ESTIMATED_EXEC_TIME. I've heard that it is also necessary to set the
> directive SWITCH_ESTIMATE to true.
> It is not clearly specified in the documentation.
> What are your opinions and experiences about it ?

You do *not* have to set switch_estimate to true to get max_estimated_exec_time to work, since that is clearly already an estimate. You're confusing two different things here. MAX_EXECUTED says 'if we think your report is going to run too long, we won't even start it'. The switch_estimate one is part of the directives which state 'we'll let your query run for X seconds, and then we're going to bump you down into a lower consumer group'. By setting switch_estimate to true, you change the meaning of that directive slightly to mean 'if we think your query will run for X seconds, we'll bump you down to the lower consumer group from the outset... but we will nevertheless let your query run'.

Regards
HJR
>
> Thanks in advance
> David Coste
> OCP 8i
>
>
Received on Wed Dec 10 2003 - 13:28:35 CST