Using IBM Heap Analyser

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Hi all,

i am new to IBM heap analyser, but i have some expericence with WAS v6.1
We are currently having some heap dump and java core files with us.

How can we detect the SOURCE CODE in the application that is causing the highest memory usage.
Or
Is there any other tool which can help us in doing so.

Can anyone help me in this regard with the steps involved in doing so.

kinldy let me know any resources which can help us in doing performance tuning activites

The heap dump and javacore 's have been generated both on RHEL 5 and Solaris machines.

Thanks in advance.

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Posted By: chandoo.ws at Aug 6 2009 4:24AM

The heap is only going to have the objects. You will have to use HA to find what objects are taking up the most room, or look to be leaking. Then based on the name of the object, determine who owns the object and have the developers of that code review. There isn't really any information to directly tie the object in the heap to the application source code that allocated it.

Beginning with SDK 1.5 SR10, there is a way to get a stack dump of the thread that allocates an object of a certain size. If the objects are large enough, this could be a possibility. But if it is just a very large number of smaller sized objects, this might be a bit cumbersome

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Posted By: cathy at Aug 8 2009 11:26AM

Take a look at the Tivoli performance Viewer which is built into WAS V6.1
And the PMAT (IBM Pattern Modeling and Analysis tool) and the MDD4J (Memory Dump Diagnostic for JAVA) in the ISA (IBM Support Assistant)

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Posted By: TGIBONEY at Aug 10 2009 6:30PM

Thanks cathy for providing with valuable information.

I really need to find out the code which causes leak.

My application has been developed and deployed by vendor. So i may not be able to catch them frequently.

Is there any other way to do the same , i have the basic knowledge of java and j2ee.

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Posted By: chandoo.ws at Aug 10 2009 7:14AM

Hi ,

I beleive you might be having out of memory error in systemout logs thats why you are looking for code leakage. Your code leakage cant be found from these tools i guess.

Mostly these errors can be rectified from your WAS side.

Try analysing your java core files and try to find out the cause for the creation of thread dumps.it can be analysed by thread analyser which can be downloaded from IBM site.

Try tuning these areas.

* Heap Space make sure you have maximum available heap size not more than 1024. Its tuned based on your RAM.
* Thread pool settings.
* Your maximum in- memory session count.

If possible send me the java core files i can analyse if you need.

Hope have helped you.

---------
Morgan

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Posted By: Morgan at Aug 11 2009 5:32AM

Thanks morgan for the reply. Your message really improves my knowledge.

I can send a javacore file , but i don't know how to attach it here (:(:

Can you please let me know the typical settings for Thread pool, and session counts..

Thanks.

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Posted By: chandoo.ws at Aug 21 2009 10:36AM

Hello Chandoo,

I think we cant attach files here you can analyse your java core files with the help of IBM read me docs.

Thread pool - It is always advisable to have less no of threads try having the maximum and mini threads as same. So that the thread can be reused efficiently.

Session count purely depends on your application you have to decide on those how many users are using your application. It should not be set the value as less than your max thread pool settings.

Thanks,
Morgan

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Posted By: Morgan at Aug 22 2009 3:22PM

Thanks Morgan ..

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Posted By: chandoo.ws at Aug 23 2009 5:13AM