Understaning native_stderr file in websphere app server

Question

All, I am getting the native_stderr.log file while running my application on Websphere App Server 7.0.0.15. earlier it used to be simple log file format, but recently I have observed that the file is in XML format.

Is there any IBM provided tool to interpret this file?

The logfile contains sections like this:

<af type="tenured" id="345" timestamp="Sep 07 15:51:45 2011" intervalms="3981.813">
  <minimum requested_bytes="16400" />
  <time exclusiveaccessms="0.163" meanexclusiveaccessms="0.163" threads="0" lastthreadtid="0x0000000032D8C700" />
  <refs soft="24731" weak="22022" phantom="1950" dynamicSoftReferenceThreshold="19" maxSoftReferenceThreshold="32" />
  <tenured freebytes="4223424" totalbytes="536870912" percent="0" >
    <soa freebytes="0" totalbytes="531503104" percent="0" />
    <loa freebytes="4223424" totalbytes="5367808" percent="78" />
  </tenured>
  <gc type="global" id="347" totalid="347" intervalms="3982.134">
    <finalization objectsqueued="786" />
    <timesms mark="677.563" sweep="8.489" compact="0.000" total="686.650" />
    <tenured freebytes="334476968" totalbytes="536870912" percent="62" >
      <soa freebytes="330253544" totalbytes="531503104" percent="62" />
      <loa freebytes="4223424" totalbytes="5367808" percent="78" />
    </tenured>
  </gc>
  <tenured freebytes="334460568" totalbytes="536870912" percent="62" >
    <soa freebytes="330237144" totalbytes="531503104" percent="62" />
    <loa freebytes="4223424" totalbytes="5367808" percent="78" />
  </tenured>
  <refs soft="24252" weak="17085" phantom="1950" dynamicSoftReferenceThreshold="19" maxSoftReferenceThreshold="32" />
  <time totalms="687.356" />
</af>

Thanks

Answer 1

That output is the JVM verbosegc trace. The file format hasn't changed, it is still flat, but someone has enabled the verbosegc log, so you are getting additional information output which is xmlish.

Their are tools which can parse this an produce pretty graphs. IBM Support Assistant contains a tool called the Garbage Collection and Memory Visualizer. There is a video of this tool including how to install instructions on IBM Education Assistant.

Answer 2

If you enable verbose garbage collection in websphere application server then you will get this kind of information. If you want to check that go to that path Server->Application Server->Server1(Click on a server where you want to see log)-> Process Definition->Java Virtual Machine-> Verbose Garbage Collection( a checkbox) Restart the server you will see the similar log in native_stderr.log file on that particular profile in logs folder. To analyze that file you need to have tool like-Tivoli® Performance Viewer, Dump JVM (DMPJVM), and WebSphere's Resource Analyzer. I think this link will help http://www.ibm.com/developerworks/websphere/library/techarticles/0706_sun/0706_sun.html

Also I have installed one performence analyzer you will get complete guide with this link- http://www.ibm.com/developerworks/websphere/library/techarticles/0811_gunasekaran/0811_gunasekaran.html#download

You have to download one jar that you will get from above link and put it in your local system and open CMD and go to that path and run this command- java -jar hsa_jdk15.jar -f D:\IBM\WebSphere\AppServer\profiles\profile1\logs\server1\native_stderr.log make change according to your configuration like path of your native_stderr.log file and give it after -f. I think it will help.