PK82536: WLM DUPLICATE NOTIFICATIONS CAUSES SIB MESSAGE FAILURES DURING FAILOVER

APAR status

• Closed as program error.

Error description

• There is a problem path in the Workload Management (WLM) code
  when running in an environment with messaging engines defined.
  The problem was seen during failover scenarios with high load,
  but may occur in low-load scenarios.  WLM erroneously sends out
  multiple notifications about the membership of the messaging
  engines in Application Server-internally defined clusters which
  leads to WLM stating there are no available messaging engines
  to route a request to despite that messaging engine being up
  and running. This APAR addresses the issue by ensuring that
  irregardless of how many times a particular ClusterObserver
  registers for updates about a resource, that only one
  notification will be sent out.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:  All users of WebSphere Application Server   *
  *                  v6 and v7 using Java Message Service (JMS)  *
  ****************************************************************
  * PROBLEM DESCRIPTION: Duplicate notifications causes          *
  *                      service integration bus (SIB) message   *
  *                      failures during failover scenario       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  There is a problem path in the WLM code when running in an
  environment with messaging engines defined.  The problem
  was seen during failover scenarios with high load, but may
  occur in low-load scenarios.  WLM erroneously sends out
  multiple notifications about the membership of the messaging
  engines in WAS-internally defined clusters which leads to WLM
  stating there are no available messaging engines to route a
  request to despite that messaging engine being up and running.
  

Problem conclusion

• This APAR addresses the issue by ensuring that regardless of
  how many times a particular ClusterObserver registers for
  updates about a resource, that only one notification will be
  sent out
  
  The fix for this APAR is currently targeted for inclusion in
  fix packs 6.0.2.35, 6.1.0.25, 7.0.0.5  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:

  PK78110

• 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

• R60A PSY

     UP

• R60H PSY

     UP

• R60I PSY

     UP

• R60P PSY

     UP

• R60S PSY

     UP

• R60W PSY

     UP

• R60Z PSY

     UP

• R61A PSY

     UP

• R61H PSY

     UP

• R61I PSY

     UP

• R61P PSY

     UP

• R61S PSY

     UP

• R61W PSY

     UP

• R61Z PSY

     UP

• R700 PSY

     UP