PK82240: WHEN AN MESSAGE-DRIVEN BEAN CONSUMES FROM A DESTINATION IN A BUS USING READ-AHEAD A DEADLOCK MIGHT BE SEEN

Fixes are available

APAR status

Closed as program error.

Error description

A message-driven bean application consuming from a
bus destination using read-ahead might become deadlocked, and
stop processing messages.

Read-ahead is used by default for non-durable (and shared
durable) subscriptions on a topic space. It can be enabled
manually for other destinations.

Local fix

WAS SIB code is being analyzed for possible cause(s) of this
deadlock. Restarting the WAS server is now  used as a work
workaround solution until a fix is made.

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 in the JVM       *
*                      hosting the messaging engine process    *
*                      when a client is receiving messages     *
*                      in read-ahead mode.                     *
*                                                              *
*                      If the deadlock is encountered no more  *
*                      messages are delivered to that client   *
*                      application.                            *
*                                                              *
*                      Read-ahead is used only when the        *
*                      application is in a different JVM       *
*                      to the messaging engine, so message     *
*                      consumption occurs over a network.      *
*                      It is enabled by default for            *
*                      nondurable subscription, and unshared   *
*                      durable subscriptions, on a topic       *
*                      destination.                            *
*                      For shared durable subscriptions, and   *
*                      consumers from queue destinations, it   *
*                      can be enabled manually.                *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
A javacore taken from the JVM hosting the messaging engine in
a system that has encountered this deadlock shows threads with
stacks similar to the following:

Thread 1:
com/ibm/ws/sib/comms/server/clientsupport/
                       CATAsynchReadAheadReader.consumeMessages(
               CATAsynchReadAheadReader.java:147(Compiled Code))
at com/ibm/ws/sib/processor/impl/AsynchConsumer.
             processMsgs(AsynchConsumer.java:105(Compiled Code))
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint.
             processAttachedMsgs(JSLocalConsumerPoint.java:1976(
                                                 Compiled Code))
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint.
runAsynchConsumer(JSLocalConsumerPoint.java:2684(Compiled Code))
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint$
 AsynchThread.run(JSLocalConsumerPoint.java:2910(Compiled Code))
at com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:1473(
                                                 Compiled Code))
Thread 2:
com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint.
    internalStart(JSLocalConsumerPoint.java:2994(Compiled Code))
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint.start
                                (JSLocalConsumerPoint.java:2978)
at com/ibm/ws/sib/processor/impl/ConsumerSessionImpl.
                             start(ConsumerSessionImpl.java:828)
at com/ibm/ws/sib/comms/server/clientsupport/CATProxyConsumer.
           requestMsgs(CATProxyConsumer.java:754(Compiled Code))
at com/ibm/ws/sib/comms/server/clientsupport/CATMainConsumer.
            requestMsgs(CATMainConsumer.java:963(Compiled Code))
at com/ibm/ws/sib/comms/server/clientsupport/StaticCATConsumer.
       rcvRequestMsgs(StaticCATConsumer.java:760(Compiled Code))
at com/ibm/ws/sib/comms/server/clientsupport/
                    ServerTransportReceiveListener.dataReceived(
         ServerTransportReceiveListener.java:519(Compiled Code))
at com/ibm/ws/sib/jfapchannel/impl/rldispatcher/
              ConversationReceiveListenerDataReceivedInvocation.
  invoke(ConversationReceiveListenerDataReceivedInvocation.java:
                                             188(Compiled Code))
at com/ibm/ws/sib/jfapchannel/impl/rldispatcher/
                               ReceiveListenerDispatchQueue.run(
           ReceiveListenerDispatchQueue.java:411(Compiled Code))
at com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:1473(
                                                 Compiled Code))

The deadlock is caused by the network communications code
incorrectly requesting delivery of messages from the messaging
engine (to send to the read-ahead queue of the client
application over the network) when the messaging engine is
already in the process of delivering a message.

Problem conclusion

The fix for this APAR prevents the deadlock from occurring by
ensuring the read-ahead related communications code does not
request asynchronous delivery messages from the messaging
engine, when asynchronous delivery of messages is already in
progress.

The fix for this APAR is currently targeted for inclusion in
fix pack 6.1.0.27 and 7.0.0.7.  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
PK82240
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
2009-03-10
Closed date
2009-04-20
Last modified date
2009-04-20

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

PK82240: WHEN AN MESSAGE-DRIVEN BEAN CONSUMES FROM A DESTINATION IN A BUS USING READ-AHEAD A DEADLOCK MIGHT BE SEEN

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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