Re: Patching terminology

From: Vladimir M. Zakharychev <>
Date: Fri, 30 Apr 2010 01:19:30 -0700 (PDT)
Message-ID: <>

On Apr 28, 6:52 pm, Chuck <> wrote:
> What is the difference between CPU, PSU, PSE, and MLR? I see all of
> these terms in the MOS (My Oracle Support) patching recommendations but
> no explanations.
> I know what a PSU and CPU are.  CPU="Critical Patch Update" and it
> includes only security related patches. PSU="Patch Set Update" and it
> includes the most recent CPU  plus additional non-security bug fixes.
> What are PSE's and MLR's though and how do I know if I really need them?
> Also I thought Oracle said once you start applying PSU's to an oracle
> home you should not revert back to CPU's, however in my OMS home I've
> applied PSU's, yet the patch recommendations both in Grid Control and
> MOS are recommending the latest CPU. Do I have it backwards? Is it ok to
> go from PSU to CPU but not CPU to PSU?

MLR = Merge Label Request. Sometimes fixes for different bugs may touch the same code, in this case they need to be merged to resolve the conflict and deliver the fixes in one package. Typically done per customer request (you are hit by two or more bugs and you find that the patches are conflicting. You request a merge, they evaluate if it's worth the effort and sometimes deliver the MLR patch.) Never seen on Windows because they always compile Windows binaries themselves. In fact, Windows patch bundles are MLRs, too, but they decide which fixes to merge themselves.


   Vladimir M. Zakharychev
   N-Networks, makers of Dynamic PSP(tm) Received on Fri Apr 30 2010 - 03:19:30 CDT

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