Re: Experience with parallel query option
Date: 1995/04/12
Message-ID: <3mhd1l$ha6_at_dcsun4.us.oracle.com>#1/1
marc.feidt_at_eurostat.cec.be (Marc FEIDT) writes:
>I have played around a little bit with the parallel query option of ORACLE
>7.1.4.
> 2) Is it useful to set the degree to a value higher than the number of
>processors on the server?
>
With Oracle7 for MVS we have set the parallel degree higher than the number of
processors. We have a 3 processor Amdahl machine running MVS. We found that
parallel degree 12 completed in about 45% of the time required for parallel
degree 3. Additionally, this only took about 7% more CPU than parallel degree 3.
This was a test using select count(*) from table where the table contains 15,000,000 rows spread over 15 volumes. Oracle7 was at 7.1.4.
I believe that the proper degree setting for your machine is going to be dependent on the operating system and underlying hardware that you are using. I have no idea at all if setting your parallel degree higher than the number of processors you have will have any impact on your platform. It does have a positive impact on MVS.
Dave Dargo (ddargo_at_us.oracle.com) Received on Wed Apr 12 1995 - 00:00:00 CEST