Re: Oracle 8i + Solaris8 + Enterprise450 + 2 CPU's

Billy Verreynne <vslabs_at_onwe.co.za> wrote in message news:<at6pfa$nc5$1_at_ctb-nnrp2.saix.net>...
> Burkhard Kiesel wrote:
>
> > we have a SUN Enterprise 450 with 2 CPU's and 2 GB RAM. How can I
> > measure the CPU performance for both CPU's. Today I use the top command.
> > Is there a special version available, which shows also the 2nc cpu ?
>
> The top command I use (HP Unix) shows the CPU - the 1st column in the top
> display is the CPU number.
>
> > Is there anything which we have to take care in oracle, that the second
> > cpu is used ?
>
> Yes and no.
>
> No - by default Oracle will use the 2nd CPU. In fact, this is more of an
> operating system issue. When the 1st CPU busy state gets to a certian
> percentage, the operating system will run new proccesses on the 2nd CPU.
> The operating system is responsible for load balancing at CPU level. Not
> application software.
>
> Yes - as you have now have increased load capacity on your system, you can
> make use of that in Oracle. For example, a full table scan can be done in
> parallel (and not serial) more effectively. Certain index scans can also be
> paralised. Thus, it is a good idea to install and configure Oracle PQ
> (Parallel Query) and to use PQ on large tables where possible.

I don't think it is a good idea to use PQ if you have only 2 CPU's. After all PQ will start up one process per CPU and a third process coordinating the 2 processes.
Also: tests shows you will *not* benefit from PQ if you haven't striped the affected tables, either in Oracle or on O/S level.

Regards

Sybrand Bakker
Senior Oracle DBA Received on Wed Dec 11 2002 - 04:05:36 CST