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Heap dump generation

former_member201054
Contributor
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Hi,

How can we know in adavance that AS Java system is going generate heap dump

please guide

Thanks a ton

Accepted Solutions (1)

Accepted Solutions (1)

Former Member
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System will generate heapdumps when it reach Out Of Memory situation if you have the parameter in place, , so you can't see it in advance.

e.g you have -XX:+HeapDumpOnOutOfMemoryError in server node for sun jdk then you'll receive system generated heapdumps.

former_member201054
Contributor
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can it be monitored anywhere prior to the error.

Former Member
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Yes, not exactly we can catch.

But we can pridect it is going to be generate , on the following based points.

a) If yr st02 swaps are very heavy,

b) If system core dumps are more

c) If system getting slow

d) Memory crunches are more

I hope it helps.

former_member201054
Contributor
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how to monitor for Java system

Former Member
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You can monitor the J2ee memory usage with solution manager diagnostics. You will have to deploy SMD agents and configure wily introscope. Search for these terms for more information.

Besides that for a quick analysis you can always check the dev_serverX / std_serverX.out files in the work directory. Here is an example:

SAP JVM 5:

1437605.051: [GC 1437605.052: [ParNew: 353500K->12204K(381696K), 0.1393900 secs] 1022884K->681626K(2059008K), 0.1400470 secs] [Times: user=0.21 sys=0.11, real=0.14 secs]

This is for NW7.1 installations, the heap is 2059008K and 681626K was used after the garbage collection. The NW 7.0 Sun java implementation looks quite similar the IBM java output is a bit different.

There are also a few standalone tools, you should search for GC Viewer, Samurai and Memory Analyzer. But use the Solman Diagnostics if available.

Cheers Michael

Former Member
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Hi All,

Yes i 100% agree to MHO answer, implement SMD agent in the source system and access via Solution manager system to find out these kind of issues and also monitor all other issues like if you have setup CTS+ then you can perform transports same as ABAP system transports for JAVA based systems.

thanks,

Macherla

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