PM21935: SIB MESSAGE DRIVEN BEANS STOP PROCESSING MESSAGES DUE TO A DEADLOCK BETWEEN THREADS WHEN A FULL SET OF MDBS ARE ACTIVE

Fixes are available

APAR status

Closed as program error.

Error description

The 'Maximum concurrent MDB invocations per endpoint' option
on a Service Integration Bus activation specification controls
the number of MDB instances which the bus will run in parallel
to process messages.  When a full set of MDBs is running, the
activation specification briefly stops message delivery.  There
is a small chance that the activation specification can deadlock
at this point, preventing further delivery of messages.
  When this problem happens, a javacore or thread dump of the
application server will show two threads deadlocked with stacks
similar to the ones below:
.
"Thread : 1"
  at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint
     .internalStop(JSLocalConsumerPoint.java:3241)
  at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint
     .stop(JSLocalConsumerPoint.java:3230)
  at com/ibm/ws/sib/processor/impl/ConsumerSessionImpl
     .stop(ConsumerSessionImpl.java:847)
  at com/ibm/ws/sib/ra/inbound/impl/SibRaSingleProcessListener$
     SibRaWork.workAccepted(SibRaSingleProcessListener.java:662)
  at com/ibm/ejs/j2c/work/WorkProxy.<init>(WorkProxy.java:194)
  at com/ibm/ejs/j2c/work/WorkManagerImpl
     .scheduleWork(WorkManagerImpl.java:356)
  at com/ibm/ws/sib/ra/inbound/impl/SibRaSingleProcessListener$
     SibRaWork.schedule(SibRaSingleProcessListener.java:546)
  at com/ibm/ws/sib/ra/inbound/impl/SibRaSingleProcessListener
     .internalConsumeMessages(SibRaSingleProcessListener.java:
     377(Compiled Code))
  at com/ibm/ws/sib/ra/inbound/impl/SibRaListener$
     $AsynchResumeCallbackImpl.run(SibRaListener.java:1055)
  at com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:
     1497(Compiled Code))
.
"Thread : 2"
  at com/ibm/ws/sib/processor/impl/AsynchConsumer
     .processMsgs(AsynchConsumer.java:105)
  at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint
     .processQueuedMsgs(JSLocalConsumerPoint.java:2161
     2161(Compiled Code))
  at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint
     .runAsynchConsumer(JSLocalConsumerPoint.java:
     2712(Compiled Code))
  at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint$
     AsynchThread.run(JSLocalConsumerPoint.java:2931)
  at com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:
     1497(Compiled Code))

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  Users of the default messaging provider     *
*                  for IBM WebSphere Application Server using  *
*                  WebSphere Virtual Enterprise or             *
*                  WebSphere Extended Deployment               *
****************************************************************
* PROBLEM DESCRIPTION: Deadlock in messaging engine whilst     *
*                      processing at the configured maximum    *
*                      concurrent endpoints, and MDB           *
*                      throttling is active.                   *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
There are two throttling systems active for default
messaging provider message-driven beans, when MDB throttling is
enabled in WebSphere Virtual Enterprise.

These two systems can disagree on the desired state of the
MDB, and might suspend and resume over the top of each other.
In some cases, causing deadlock. In other cases, causing an
unexpectedly large number of concurrent MDB instances.

Problem conclusion

The code has been altered to ensure that the two throttling
systems operate correctly. An MDB will only be active when both
throttling mechanisms agree that it should be.

With the fix for this APAR applied, the maximum number of
threads that can be active for an MDB concurrently (per
endpoint) is defined by the "Maximum concurrent endpoints"
setting of the activation specification. WebSphere Extended
Deployment might further limit the number of concurrent MDB
instances below this number (while it cannot extend the number
of current MDB instances beyond this limit).

The fix for this APAR is currently targeted for inclusion in
fix pack 6.1.0.37, and 7.0.0.15.  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 number
PM21935
Reported component name
PLAT MSG COM
Reported component ID
620600101
Reported release
200
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2010-09-03
Closed date
2010-10-29
Last modified date
2010-10-29

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
PLAT MSG COM
Fixed component ID
620600101

Applicable component levels

R200 PSY
UP

[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSEQTP","label":"WebSphere Application Server"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.1","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
24 October 2021

Tips

PM21935: SIB MESSAGE DRIVEN BEANS STOP PROCESSING MESSAGES DUE TO A DEADLOCK BETWEEN THREADS WHEN A FULL SET OF MDBS ARE ACTIVE

Fixes are available

Subscribe

APAR status

Closed as program error.

Error description

Local fix

Problem summary

Problem conclusion

Temporary fix

Comments

APAR Information

APAR number

Reported component name

Reported component ID

Reported release

Status

PE

HIPER

Special Attention

Submitted date

Closed date

Last modified date

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

Fixed component ID

Applicable component levels

R200 PSY

Document Information

Share your feedback

Need support?