From: Charles Hooper <>
Date: Fri, 4 Sep 2009 15:25:14 -0700 (PDT)
Message-ID: <>

On Sep 4, 2:09 pm, Sue <> wrote:
> Does anyone know what CPU_COUNT means on a mulit-core machine?  Say
> you have a four core cpu.  Does setting CPU_COUNT to 1 use all 4 cores
> on 1 CPU or 1 core on a CPU?

Changing CPU_COUNT to 1 is not the right solution, as others have mentioned. It will change some of Oracle automatic configuration settings, such as the number of default DB writers, but it will not confine Oracle to using only a single CPU (or CPU core) as it is the operating system's responsibility to schedule threads and processes on (or across) all CPUs.

That said, you may want to check the licensing information for your edition of Oracle and the particular CPUs in the server. For instance, Intel and AMD processors are currently licensed at 0.5 CPUs per core in multi-core CPUs with the Enterprise Edition (thus 2 CPUs license for a quad core Intel), and for Standard Edition only the CPU socket is counted (thus 1 CPU license for a quad core). Other CPU platforms have a 0.25 conversion factor for the Enterprise Edition (and others might have a 0.75 conversion factor).

A quad core Nehalem (Xeon 5500 series or Core i7) will report a total of 8 CPUs in Oracle, but I believe that this still counts as a 4 core CPU. Charles Hooper
IT Manager/Oracle DBA
K&M Machine-Fabricating, Inc. Received on Fri Sep 04 2009 - 17:25:14 CDT

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