Re: PARALLEL QUERY
- From: "Roman Podshivalov" <roman.podshivalov@xxxxxxxxx>
- To: oracle.tutorials@xxxxxxxxx
- Date: Tue, 16 Oct 2007 09:23:02 -0400
Hi,
During sequential run check out v$px_sessstat/v$px_session views. You might
find some info there. Views have 2 columns REQ_DEGREE and DEGREE. First one
should list 4 since you've requested it with hint and satisfied degree
should be 1, I guess. But to understand why optimizer lowered your degree -
as Dave said above review 10053 trace.
BTW, how many parallel servers configured on the system ?
(parallel_max_servers)
--romas
On 10/16/07, DBA Deepak <oracle.tutorials@xxxxxxxxx> wrote:
>
> Hi Experts,
>
> Have a problem related to parallel query execution. I have a setup of
> Oracle 10g (10.2.0.3) on solaris 64 bit and on a 16 core CPU system.
>
> When I execute parallel hint in the query the following happens.
>
> Does not use PQ processes for the query:
>
> select /*+ parallel(bt,4) */ from big_table bt;
>
> Does use PQ processes for the query:
> select /*+ parallel(bt,16) */ from big_table bt;
> Please help me in understanding why this happens.
>
>
> --
> Regards,
>
> Deepak
> Oracle DBA
>
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