Understaning native_stderr file in websphere app server

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

Solution

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.