PM34003: MESSAGES CONTINUE TO ACCUMULATE FOR A SUBSCRIBER THAT HAS DISCONNECTED

Fixes are available

APAR status

Closed as program error.

Error description

Messages build up on Websphere Application Server v6.1.x
Service Integration Bus Topic Destination

Javacores collected from the JVM hosting the messaging
engine show a livelock where thread 1 waits to acquire a lock
indefinitely while another thread, thread 2, holds the lock.
Thread 2 is not blocked, but never releases the lock.

Thread 1:
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint.close
(JSLocalConsumerPoint.java:2766(Compiled Code))
at com/ibm/ws/sib/processor/impl/ConsumerSessionImpl._close
(ConsumerSessionImpl.java:619(Compiled Code))
at com/ibm/ws/sib/processor/impl/ConnectionImpl._close
(ConnectionImpl.java:593(Compiled Code))
at com/ibm/ws/sib/processor/impl/ConnectionImpl.close
(ConnectionImpl.java:489(Compiled Code))
at com/ibm/ws/sib/comms/server/clientsupport/ServerTransport
ReceiveListener.cleanupConnection(ServerTransportReceive
Listener.java:922(Compiled Code))
at com/ibm/ws/sib/comms/server/clientsupport/ServerTransport
AcceptListener.removeAllConversations(ServerTransportAccept
Listener.java:273(Compiled Code))
...

Thread 2:
...
at  com/ibm/ws/sib/comms/server/clientsupport/CATProxyConsumer.
sendMessage(CATProxyConsumer.java:758(Compiled Code))
at com/ibm/ws/sib/comms/server/clientsupport/CATAsynchReadAhead
Reader.consumeMessages(CATAsynchReadAheadReader.java:130
(Compiled Code))
at com/ibm/ws/sib/processor/impl/AsynchConsumer.processMsgs
(AsynchConsumer.java:105(Compiled Code))
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint.process
AttachedMsgs(JSLocalConsumerPoint.java:2015(Compiled Code))
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint.runAsynch
Consumer(JSLocalConsumerPoint.java:2705(Compiled Code))
at com/ibm/ws/sib/processor/impl/JSLocalConsumerPoint$Asynch
Thread.run(JSLocalConsumerPoint.java:2931(Compiled Code))
at com/ibm/ws/util/ThreadPool$Worker.run(ThreadPool.java:1497
(Compiled Code))

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  Users of the default messaging provider for *
*                  IBM WebSphere Application Server            *
****************************************************************
* PROBLEM DESCRIPTION: Messages continue to accumulate for a   *
*                      subscriber that has disconnected.       *
****************************************************************
* RECOMMENDATION:                                              *
****************************************************************
A live lock during the disconnection of a non-durable
subscriber
(usually due to a network outage) can prevent the
de-registration of the subscriber from the messaging engine.
This results in the accumulation of messages for this subscriber
eventually resulting in the destination depth threshold
(CWSIP0553W) being reached or the message store becoming full
(CWSIS1575E).

Unexpected CPU load on the server hosting the messaging engine
will also occur.

This live lock is the result of read ahead consumers
(subscribers are read ahead consumers by default) failing to
stop the consumer when the connection the read ahead consumer
is attempting to send data to is closed asynchronously.  While
sending message data, the consumer holds a lock.  This lock is
needed to cleanup the connection, so the cleanup cannot
proceed until the consumer stops.

Problem conclusion

This APAR resolves the problem by stopping the consumer when
the connection is closed.  Thus the lock is released and the
connection cleanup can proceed.

The fix for this APAR is currently targeted for inclusion in
fix pack 6.1.0.41 and 7.0.0.19.  Please refer to the
Recommended Updates page for delivery information:
http://www.ibm.com/support/docview.wss?rs=180&uid=swg27004980

Temporary fix

```
Disable read ahead.
```

Comments

APAR Information

APAR number
PM34003
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
2011-03-03
Closed date
2011-05-24
Last modified date
2011-05-24

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:
27 October 2021

Tips

PM34003: MESSAGES CONTINUE TO ACCUMULATE FOR A SUBSCRIBER THAT HAS DISCONNECTED

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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