PK92871: MQEXCEPTION MQRC 2012 USING WMQ ON 64 BIT JVMS

Fixes are available

APAR status

Closed as program error.

Error description

With 64 bit JVMs, an MQException with MQRC 2012 is thrown,
seemingly randomly, when a transaction is committed:

com.ibm.mq.MQException: MQJE001: Completion Code 2, Reason 2012
at com.ibm.mq.MQQueueManager.commit(MQQueueManager.java:2220)
at com.ibm.mq.jms.MQSession.commitQ(MQSession.java:3779)
at com.ibm.mq.jms.MQQueueSession.commit(MQQueueSession.java:154)
at
com.ibm.ejs.jms.JMSManagedSession$JMSLocalTransaction.commit(JMS
ManagedSession.java:1201)
at
com.ibm.ejs.j2c.LocalTransactionWrapper.commit(LocalTransactionW
rapper.java:259)

The cause of the problem could result in other symptoms that
have not yet been observed.

Local fix

Problem summary

****************************************************************
* USERS AFFECTED:  All users of WebSphere Application Server   *
*                  V6.1                                        *
****************************************************************
* PROBLEM DESCRIPTION: MQException MQRC 2012 thrown at         *
*                      transaction commit.  There could be     *
*                      other symptoms of this problem that     *
*                      are not yet known.                      *
****************************************************************
* RECOMMENDATION:  Apply the fix for this APAR, and the fix    *
*                  fix for APAR PM11632                        *
****************************************************************
The System.identityHashCode() method (Object.hashcode()) is
not assured to provide unique values. The WebSphere
Application Server messaging code was incorrectly assuming
that the hashcode is unqiue, and using it to construct a
unique identifier within the WebSphere MQ JMS Provider, to
identify an internal connector (the JMS Session pools) to
J2C.

If two different connectors had the same identifier, when one
is cleaned up, the other that should still be active has some
state removed.  This can result in the exception described,
but equally could result in some other, seemingly random,
problem.

It is very unlikely that two Objects would have the same
hashcode, let alone two Objects used in a group of say 30 (the
number of JMS Connections in the pool).  On Z/OS, however, the
implementation of hashcode frequently produces the same int
for different Objects, making the likelihood of this problem
occurring higher.

The likelihood of hitting this problem is also increased when
many JMS Connections are created and destroyed. This scenario
is possible when there are many requests of Connections using
different user aliases, so J2C must destroy one Connection to
create another suitable Connection with the correct
credentials if the J2C Connection pool is already full.

Non-unique hashcodes have been seen to be more likely to cause
problems on 64 bit JVMs. However, non-unique hashcodes are
possible on 32 bit JVMs as well, so this APAR applies to both
64 bit and 32 bit JVMs.

Problem conclusion

This APAR fixes the problem by generating unique IDs for each
connector, and no longer relies on hashcode.

APAR PK92871 is currently targeted for inclusion in Service
Level (Fix Pack) 6.1.0.29 and 7.0.0.8 of WebSphere Application
Server V6.1.

Please refer to URL:
//www.ibm.com/support/docview.wss?rs=404&uid=swg27006970
for Fix Pack availability.

Temporary fix

```
ZE Fix Error, see PM11632   2010/04/13
```

Comments

APAR Information

APAR number
PK92871
Reported component name
WEBSPHERE FOR Z
Reported component ID
5655I3500
Reported release
610
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2009-07-31
Closed date
2009-10-05
Last modified date
2010-08-04

APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:

PM02879

Fix information

Fixed component name
WEBSPHERE FOR Z
Fixed component ID
5655I3500

Applicable component levels

R610 PSY UK53194
UP10/01/15 P F001

Fix is available

Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SS7K4U","label":"WebSphere Application Server for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.1","Line of Business":{"code":"LOB45","label":"Automation"}}]

Document Information

Modified date:
28 December 2021

Tips

PK92871: MQEXCEPTION MQRC 2012 USING WMQ ON 64 BIT JVMS

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

R610 PSY UK53194

Fix is available

Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.

Document Information

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