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Need answers on what C-Runtime heap is

We recently did an upgrade to DB2 and even more recently OnDemand (an IBM image archive app) on our AIX box and now we're having huge problems running an application.  We are trying to configure JProbe to help, but in the meantime I'd like more information on the error.  The error is the following:

JVMCL052 - Cannot allocate memory in initializeHeap for heap segment

From my understanding, this is NOT the java heap.  Read these comments below:

"The C-runtime heap of the process (not the Java object heap) is full. Increase the heap if that is possible in your environment. In a shared classes environment, see the shared classes User Guide for options that control shared memory, because the storage is managed by the JVM in this case."

The app is being ran on AIX version 5.3.  I don't know what C-runtime heap is or how to increase it.  I'm not the AIX administrator and my request has fallen on deaf ears.  This app ran much smoother in the past, so I know something with the OnDemand or DB2 upgrade has leached the AIX resources.  

Can someone help??
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jackjeckyl
Asked:
jackjeckyl
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2 Solutions
 
gheistCommented:
This is JVM error (not able) allocating data pages from system.
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jackjeckylAuthor Commented:
So what do I do?
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gheistCommented:
check ulimit -a
then use smitty to increase allowed (data ?) size to -1 or something less.
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woolmilkporcCommented:
Might be that your Java heap is too big, so that no C heap is left for non-java-heap purposes (internal JVM functions etc.) Try to reduce it (-Xmx ... option)
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jackjeckylAuthor Commented:
gheist - everything is set to unlimited, except stack (32768), coredump (2048) and nofiles (2000).  Does any of that need to be changed.

woolmilkporc - I'll try reducing the java heap, although this was set low to begin with when I had these problems.  
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gheistCommented:
Yes - it uses stack extensively.
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jackjeckylAuthor Commented:
woolmilkporc - Your suggestion worked, somewhat.  I lowered it, and now it seems to be running better on the bigger jobs the application encounters.  However, I do get java heap errors sporadically.  I went from 2GB to 1.5GB.  Maybe I'll bump it to 1.75GB and see what happens.  

gheist - Increase the stack to what value?  I'm AIX illiterate, so if I suggest something to the AIX admins, I need to tell them what and how come.  
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gheistCommented:
I suggest doubling.
Might be you hit 13x256MB limit - patching java with ML package is known to help. Also thruput GC is better.
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