Looking for the Garbage Collection log files

[Former Member]

Hello,

I am looking for the Garbage Collection log files which contain the GC events, like this:

[GC 2095K->1709K(2160K), 0.0017628 secs]

[Full GC 2161K->1018K(2276K), 0.0576353 secs]

The server's GC is already configured accordingly:

–verbose:gc

I have examined the std_server<x>.out files at the work folder but can't see this info.

My question is: Where would I find these files on the server?

[Former Member]

SAP Note 697062 - Location of JVM options and JVM output in SAP J2EE 6.20

Thanks

Kalyan

[Former Member]

Hi Roy

According to the Java platform-independence I would suggest that the format is always the same, but I am not sure on that. The information should be found either in dev_server* or std_server*

Regards,

Jan

[Former Member]

>> <i>According to the Java platform-independence I would suggest that the format is always the same</i>

In that case why does your tool has got a list of supported JVMs...

Roy

[Former Member]

It's not only reading the log files but also getting information directly from the (supported) JVM at runtime.

Jan

[Former Member]

I can't find info in the format I know it not at dev_server* or std_server*.

in std_server I see xml file like this:

<gc type="scavenger" id="1" totalid="1" intervalms="0.000">

<flipped objectcount="303111" bytes="24994248" />

<tenured objectcount="0" bytes="0" />

<refs_cleared soft="429" weak="4329" phantom="0" />

<finalization objectsqueued="1711" />

<scavenger tiltratio="50" />

<nursery freebytes="497866672" totalbytes="524288000" percent="94" tenureage="10" />

<tenured freebytes="1094921936" totalbytes="1098907648" percent="99" >

<soa freebytes="1039977168" totalbytes="1043962880" percent="99" />

<loa freebytes="54944768" totalbytes="54944768" percent="100" />

</tenured>

<time totalms="185.585" />

</gc>

I guess this is the info I need but it's not formatted in a way that your tool can read it and having a tool like this reading it is very helpful.

Any ideas?

[Former Member]

In this case I can only provide you a link to some documentation as I have not worked on IBM SDK for Java before.

http://download.boulder.ibm.com/ibmdl/pub/software/dw/jdk/diagnosis/diag60.pdf

http://publib.boulder.ibm.com/infocenter/javasdk/v1r4m2/index.jsp?topic=/com.ibm.java.doc.diagnostic...

Maybe you find something here.

Good luck and best regards,

Jan

[norbert_sieker]

You will find the verbose GClog output per default in std_server?.out.

IBM JDK has its own GC log format, incompatible with Sun JDK's, e.g. there is no FullGC (but Global GC), the heap organization resp. its garbage collector is quite special too.

Anyway, IBM offers tools for analyzing the GC logs:

- http://www.alphaworks.ibm.com/tech/gcdiag

- http://www.alphaworks.ibm.com/tech/pmat

regards, Norbert

[Former Member]

Hi Roy,

You could check if the standard location for the GC log has been changed via the the option -Xloggc:<file> to log to a seperate file.

Another thing that might help you could be a specific tool called GCViewer.

The following link can give you an overview on this:

http://www.javaperformancetuning.com/tools/gcviewer/index.shtml

Hope this helps,

Jan

[Former Member]

Hi Jan,

The location of the GC hasn't changed.

When I open std_server.out I see information related to the GC but it appears to be an xml file which I can't quite understand how to read. We are running the app server on AIX 5.3 ML5. Could be a different GC format?

Roy