PH16983: USE TRIGGERDUMP WITH REQUEST=EXCLUSIVE INSTEAD OF SYSTEMDUMP

9.0.5.2: WebSphere Application Server traditional Version 9.0.5 Fix Pack 2
8.5.5.17: WebSphere Application Server V8.5.5 Fix Pack 17
9.0.5.3: WebSphere Application Server traditional Version 9.0.5 Fix Pack 3

APAR status

• Closed as program error.

Error description

• A Java core dump may be corrupt when generated during garbage
  collection.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: The generateSystemDump operation of     *
  *                      the JVM MBean may generate a dump       *
  *                      file containing inconsistent data.      *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  The generateSystemDump operation may generate a dump file
  containing inconsistent data whenever the thread which
  produces the dump executes while garbage collection operations
  are running, especially when heap memory is near exhaustion.
  For IBM SDKs, APAR PH16983 modifies generateSystemDump to
  specify the exclusive option to the JVM dump agent when
  triggering a system dump.  The exclusive option helps ensure
  the dump contains consistent data by scheduling the thread
  that produces the dump to wait for Java threads and garbage
  collection operations to halt/complete before writing the
  data.
  JVM MBean operations, including generateSystemDump, may be
  invoked indirectly via the Administrative Console or directly
  via the wsadmin utility to manually generate Java dumps and
  core files.
  To generate a system dump for <server> on <node> using the
  wsadmin utility:
  1. Start the wsadmin scripting client
  2. Invoke the generateSystemDump operation on a JVM MBean:
  2.a. Using Jacl:
  > set objectName [$AdminControl queryNames
  WebSphere:type=JVM,process=<server>,node=<node>,*]
  > $AdminControl invoke $objectName generateSystemDump
  2.b. Using Jython:
  > objectName = AdminControl.queryNames('WebSphere:type=JVM,
  process=<server>,node=<node>,*')
  > print AdminControl.invoke(objectName, 'generateSystemDump')
  To learn more about generating Java dumps and core files,
  visit the IBM Knowledge Center topic
  "Collecting Java dumps and core files using the administrative
  console" at URL:
  https://www.ibm.com/support/knowledgecenter/SSEQTP_9.0.5/com.ibm
  .websphere.base.doc/ae/utrb_dumpcore.html
  

Problem conclusion

• Apply APAR PH16983 to specify the exclusive option to the dump
  agent when triggering a system dump on IBM JVMs.
  
  The fix for this APAR is currently targeted for inclusion in
  fix pack 9.0.5.2 and 8.5.5.17.  Please refer to the Recommended
  Updates page for delivery information:
  http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980
  

Temporary fix

Comments

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

Fix information

• Fixed component name

  WEBS APP SERV N

• Fixed component ID

  5724H8800

Applicable component levels

• R850 PSY

     UP

• R900 PSY

     UP