Re: Monitoring parallelism

Queries are parallelized when you tell Oracle to parallelize them ...

example:
Select /*+ ordered PARALLEL(tab1 4) FULL(tab1) */ from tab1, tab2
where tab1.col1 = tab2.col1
/

Or you specify the degree of parallelism on the table level: create table tab1 .....
parallel 4
/

or you can rebuild index in parallel ...

there are other various instances ....

Before you do anything, please get your "parallel" fundamentals right by referring to a good perf tuning book .. or refer to the perf tuning documentation by oracle. Otherwise, you might do more harm to the system .. than good.

Anurag

"Rick Denoire" <100.17706_at_germanynet.de> wrote in message news:q5kvluo1hhhljkl7eomp2dgtomeb5cd6gj_at_4ax.com...
> Hello
>
> I switched on parallel query by setting the init parameter
> PARALLEL_AUTOMATIC_TUNING=true and restarting the DB. Additionally, I
> set the max. number of parallel servers to 40 and the number of
> threads per CPU to 6.
>
> I haven't noticed any significant change in performance. How can I
> somehow see that parallelism is active at all? I understand that
> parallel query does not always result in a performance increase, but I
> am not sure that there is any parallelism at all. (Using Oracle
> 8.1.7/Solaris 2.7 on a Sun E3500 with 4 CPUs). If any long running job
> starts, it sticks to one CPU so the overall CPU usage never goes over
> 25%. I assume that if parallelism of any kind would be in effect, at
> least for some short periods of time the job would show a CPU usage
> above 25%. Most of the time, when only one job runs, the other 3 CPUs
> are sitting there doing almost nothing.
>
> Any sugestions?
>
> Thanks
>
> Rick
>
Received on Sun Aug 18 2002 - 14:42:02 CDT