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7 Replies Latest reply: Feb 12, 2013 1:32 PM by user593469 RSS

How to take a heap dump

Sahasra Newbie
Currently Being Moderated
Hi all,

our production weblogic servers are getting crashed. there are stuck threads and server is getting crashed with out of memory. I took the thread dump but i am not familiar with heap dump.

So, are there any commands to take a heap dump or any tools to take a heap dump. If you have any documentation on analysing the heap dump, it would be much helpful. Which is the best tool for analysing heap dump.
  • 1. Re: How to take a heap dump
    815319 Newbie
    Currently Being Moderated
    Hi.

    Check JVM Options as follow.

    -XX:+HeapDumpOnOutOfMemoryError
    -XX:+HeapDumpOnly

    Based on HP Unix.

    Edited by: Kyoungmin Lee on 2011. 3. 30 오후 7:02
  • 2. Re: How to take a heap dump
    Akshay Koul Explorer
    Currently Being Moderated
    Refer:-

    http://wiki.eclipse.org/index.php/MemoryAnalyzer#Getting_a_Heap_Dump

    http://www.bonitasoft.org/blog/eclipse/acquire-heap-dump-from-mat/

    http://download.oracle.com/javase/1.5.0/docs/tooldocs/share/jmap.html

    http://download.oracle.com/javase/6/docs/technotes/tools/share/jmap.html

    &

    http://dev.eclipse.org/blogs/memoryanalyzer/

    http://dev.eclipse.org/blogs/memoryanalyzer/2008/05/27/automated-heap-dump-analysis-finding-memory-leaks-with-one-click/

    http://dev.eclipse.org/blogs/memoryanalyzer/2008/04/21/immortal-objects-or-how-to-find-memory-leaks/

    -Akshay
  • 3. Re: How to take a heap dump
    794514 Pro
    Currently Being Moderated
    Hi Sahasra,

    I would suggest you to have a look at the below links which would surely help and also would give you a better idea how to avoid such situations.

    Topic: WebLogic Heap Dump Genration Using Jmap
    http://middlewaremagic.com/weblogic/?p=2241

    Topic:  Heap Dump Using Jhat for WebLogic Server Heap Analysis
    http://middlewaremagic.com/weblogic/?p=2202

    For percussion

    Topic:OutOfMemory Causes and First Aid Steps?
    http://middlewaremagic.com/weblogic/?p=4464

    Topic: Causes and First Aid of JVM Crash Issues?
    http://middlewaremagic.com/weblogic/?p=4482

    Regards,

    Ravish Mody
    http://middlewaremagic.com/weblogic
    Come, Join Us and Experience The Magic…
  • 4. Re: How to take a heap dump
    Sahasra Newbie
    Currently Being Moderated
    Thanks a lot. Will go through them.
  • 5. Re: How to take a heap dump
    supratim Newbie
    Currently Being Moderated
    You can connect to the admin server with wlst and fire dumpStack() to get the dump. You can also redirect to a file for later reference.
  • 6. Re: How to take a heap dump
    user593469 Newbie
    Currently Being Moderated
    This options works only when we restart the server and again when the server goes out of memory we can get the heapdump as per the arguments which you mentioned.

    But how to collect a heapdump of a server which ran out of memory and which did not have those arguments of "-XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath="
  • 7. Re: How to take a heap dump
    user593469 Newbie
    Currently Being Moderated
    Hi Could you elaborate more on this. I tried it but it seems it dumps stack traces and not heap dump.


    :)

    Edited by: 987680 on Feb 12, 2013 1:32 PM

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