PK98587: SIBUS CLIENTS ASYNCHRONOUSLY CONSUMING MESSAGES CAN DEADLOCK WITH A THREAD STUCK IN ASYNCHCONSUMERPROXYQUEUEIMPL.STOPPING()

Fixes are available

APAR status

Closed as program error.

Error description

When multiple Service Integration Bus clients are asynchronously
consuming messages from a bus destination, a deadlock can occur
between two threads which will prevent further message delivery.
A thread dump gathered at this time will show two threads
blocked in methods similar to these:
.
  "Asynchronous Consumer : 0"
    at com/ibm/ws/sib/comms/client/proxyqueue/impl/
         AsynchConsumerProxyQueueImpl.deliverMessages()
    at com/ibm/ws/sib/comms/client/proxyqueue/asynch/
         AsynchConsumerThreadPool$ScheduleQueue.run()
    at com/ibm/ws/util/ThreadPool$Worker.run()
.
  "Asynchronous Consumer : 1"
    at java/lang/Object.wait()
    at java/lang/Object.wait()
    at com/ibm/ws/sib/comms/client/proxyqueue/queue/
         AsynchConsumerQueue.waitUntilEmpty()
    at com/ibm/ws/sib/comms/client/proxyqueue/impl/
         AsynchConsumerProxyQueueImpl.stopping()
    at com/ibm/ws/sib/comms/client/
         ConsumerSessionProxy.stop()
    at com/ibm/ws/sib/comms/client/
         ConsumerSessionProxy.performInCallbackActions()
    at com/ibm/ws/sib/comms/client/proxyqueue/queue/
         AsynchConsumerQueue.deliverBatch()
    at com/ibm/ws/sib/comms/client/proxyqueue/impl/
         AsynchConsumerProxyQueueImpl.deliverMessages()
    at com/ibm/ws/sib/comms/client/proxyqueue/asynch/
         AsynchConsumerThreadPool$ScheduleQueue.run()
    at com/ibm/ws/util/ThreadPool$Worker.run()

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  Users of the default messaging provider for *
*                  IBM WebSphere Application Server Version 6.1*
*                  or Version 7.0                              *
****************************************************************
* PROBLEM DESCRIPTION: A deadlock might occur if a runtime     *
*                      exception is thrown after an            *
*                      asynchronous message consume stops      *
*                      consumption of messages                 *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
The deadlock occurs when an asynchronous consumer stops
consumption of messages within the asynchronous message
callback, and subsequently a runtime exception is thrown (such
as that seen in PK85488).

Incorrect handling of the runtime exception, within the
default messaging provider client code, causes more messages to
be requested from the messaging engine, even though the stop
requested by the asynchronous callback is being actioned.
If these messages arrive before the stop has been completely
actioned, then the deadlock occurs between the consuming thread
waiting for the in-flight message to be consumed, and another
thread waiting for the consuming thread to become available.

In Version 6.1, the issue only occurs when using the Web
messaging service that is part of the WebSphere
Application Server Version 6.1 Feature Pack for Web 2.0.
In Version 7.0, any client application that stops consumption
of messages within an asynchronous message callback might see
this issue (as well as the Web message service).

Problem conclusion

The fix for this APAR corrects the exception handling to
prevent a new batch of messages being requested from the
messaging engine when an exception is thrown after an
asynchronous consume stops consumption of messages.

The fix for this APAR is currently targeted for inclusion in
fix pack 6.1.0.31 and 7.0.0.9.  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
PK98587
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
2009-10-14
Closed date
2009-12-21
Last modified date
2009-12-21

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":"BU059","label":"IBM Software w\/o TPS"},"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:
29 December 2021

Tips

PK98587: SIBUS CLIENTS ASYNCHRONOUSLY CONSUMING MESSAGES CAN DEADLOCK WITH A THREAD STUCK IN ASYNCHCONSUMERPROXYQUEUEIMPL.STOPPING()

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

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