Issue resolutions

["Mike Silvers" <msilvers@xxxxxxxxxxx>]

All,

I was having a problem with my Apache/Tomcat server on the iSeries.  I
called IBM and they walked me through a few things.  I found out through
this that there was some bad code, but I would like to share some of the
troubleshooting info passed on to me by IBM.

Symptom:  The primary Apache HTTP server job was taking over 90% of the CPU.
Problem:  A servlet was stuck in a loop
Problem Analysis:
  1.. First, we looked at the threads in this job.  For an In-Process Tomcat
server, each request is handled by a thread within the server job.  To look
at the threads, take an option 5 on the http server job, then an option 20.
  2.. We identified the thread that was in "RUN" status.  This is the thread
that is running at the current time.  Note the thread number.
  3.. Take an option 10 against the running thread to view the call stack.
This will provide some information as to the current process that is being
run.
  4.. Use the command DMPJVM with the job information for the http server
job.  This command dumps the JVM call stack to a spooled file.  Normally,
this command does not end the job.  There are situations where this command
will end the job, but this would be related to the point in garbage
collection for the JVM and is out of our control.
  5.. Review the spooled file to determine the problem.
I hope this is helpful to others.

Mike


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Mike Silvers
Senior Programmer/Analyst
iSeries Websphere Certified
Hainey Business Systems
Main Office:  (717) 718-9601 ext 237
Branch Office:  (410) 219-2695
Fax: (877) 804-9589
http://www.hbs-inc.com
AIM:  IBMJavaMan
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