PH69763: DUPLICATE TASK ID IN SCHEDULER SERVICE

APAR status

• Closed as program error.

Error description

• When multiple JVMs reference the same scheduler database, each
  JVM is expected to receive a unique task ID range to maintain
  task ID uniqueness. However, due to a race condition, the same
  ID range may be assigned to multiple JVMs, resulting in
  duplicate task IDs.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of IBM WebSphere Application      *
  *                  Server                                      *
  ****************************************************************
  * PROBLEM DESCRIPTION: When multiple JVMs are configured to    *
  *                      use the same scheduler database,        *
  *                      duplicate task IDs may be generated.    *
  *                      This can occur intermittently due to    *
  *                      concurrent access, where more than      *
  *                      one JVM receives the same task ID       *
  *                      range. As a result, users may observe   *
  *                      task scheduling conflicts, unexpected   *
  *                      task execution behavior, or errors      *
  *                      related to duplicate task identifiers   *
  *                      in the scheduler database.              *
  ****************************************************************
  During analysis, it was observed that when multiple JVMs connect
  to and use the same scheduler database, a race condition can
  occur while allocating task ID ranges. Due to the lack of proper
  synchronization during this allocation process, the same task ID
  range may be assigned to more than one JVM instance. This leads
  to duplicate task IDs being generated and stored in the
  scheduler database.
  

Problem conclusion

• The fix for this APAR is targeted for inclusion in fix pack
  9.0.5.27, 8.5.5.30. For more information,see 'Recommended
  Updates for WebSphere Application Server':
  https://www.ibm.com/support/pages/node/715553
  

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