Dificulty generating Heap dump....

[#1]

Hi,

We are on NW04s SPS 12 on JAVA with Solaris and Oracle.

We get OutOfMemory on intermittent basis and I want to take a heap dump.

It is taking forever to take the dump and it consumes lots of memory on the server to generate a dump.

Last time it took almost 6GB and dump was not complete. It ran for 30 mnts. It dumped only 50MB. It starts writing to a file but eventually I kill it because it takes too long and lots of memory.

I am taking a dump using a jmap command u2013

/usr/sap/j2se/j2sdk1.4.2_13/bin/jmap -d64 -heap:format=b <pid>

I am little afraid to put the parameter in Visual Admin to get the dump because it may crash the box or the dump may never complete.

Please let me know if I am doing anything wrong.

I will appreciate your help.

Regards.

SC

[Former Member]

Hello Sume,

Please refer to the note 1004255

&

How can I get a heapdump ?

https://wiki.sdn.sap.com/wiki/pages/viewpage.action?pageId=33456

you need these parameters configured correctly for the engine to generate a heapdump on out of memory situation. By itself, the parameters don't cause any issues/crashing of the system. You can only generate heapdump manually when the parameter -XX:+HeapDumpOnCtrlBreak is maintained. The command to generate a heapdump manually is kill -3 which is the same as generating threaddump as well. Usually, SAP support rarely recommends generating a heapdump manually. If you have OOM issues, we need the heapdump which is generated automatically at that time for the correct analysis.

Regards,

Snehal