A fix is available
APAR status
Closed as program error.
Error description
A failure occurs during publish processing (eg. queue full in which case messages will end up on the Dead Letter Queue). When CSQIMPUS ( or CSQIMPU2 ) detect the failure they will release all locks (including those for any previous messages put within the nested unit of work which may be messages intended for other subscribers). Since these locks are released these messages may be got even if they are actually not yet committed. Later, commit processing for publish completes and the get-cursor is updated to point to one of the messages that has been got. However, the page holding the message may have now been scavenged and used (as an example) for an IRHA. Then for the next MQGET against the queue the get-cursor is used to start searching for messages but as this points to an IRHA this abend results. . The above problem may also result in a 5C6-00C90B00 abend issued by CSQIMGE9.
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: All users of WebSphere MQ for z/OS Version 7 * * Release 0 Modification 1 and Release 1 * * Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: A failure to deliver a publication to a * * subscriber's queue (for example, if the * * pageset or cfstruct is full) can cause * * locks on messages put earlier in the * * publish operation to be released * * prematurely, leading to unpredictable * * results. * * * * Observed symptoms can include: * * - Uncommitted messages that were put * * earlier in the same publish operation * * being returned on MQGET * * - 5C6-00C90900 in CSQILPLM.CSQIMGE9 * * - 0C4 in CSQILPLM.CSQIKRCD * * - Qmgr termination S6C6 REASON=00E50705 * **************************************************************** * RECOMMENDATION: * **************************************************************** While publishing to a topic with NPMSGDLV/PMSGDLV set to ALL or ALLDUR, a nested unit of work is started by CSQMTPUT. If an error occurs while putting to a subscriber queue, CSQLRELL is called to release all request locks acquired by the current put operation, however this call incorrectly releases locks relating to the put of messages to other subscribers by the same publish operation. Following this applications are able to get the messages put earlier in the publish operation prior to them being committed. This can lead to commit/abort processing referencing pages that have been deallocated and reused, leading to unpredictable results, including the reported abends.
Problem conclusion
CSQLRELL is changed to only release request locks associated with the current request, when called within a nested unit of work (for example, a publish operation). 010Y 100Y CSQLGETL CSQLRELL CSQLRSAV CSQLSLKO CSQLSVTL CSQL1ALL CSQL1INI CSQL1RCL CSQL211M CSQWCBD CSQ7CBL CSQ7CBU
Temporary fix
********* * HIPER * *********
Comments
×**** PE14/05/08 FIX IN ERROR. SEE APAR PI14103 FOR DESCRIPTION
APAR Information
APAR number
PM99383
Reported component name
WMQ Z/OS V7
Reported component ID
5655R3600
Reported release
100
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2013-10-17
Closed date
2014-01-17
Last modified date
2014-05-30
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI14313 UI14314
Modules/Macros
CSQLGETL CSQLRELL CSQLRSAV CSQLSLKO CSQLSVTL CSQL1ALL CSQL1INI CSQL1RCL CSQL211M CSQWCBD CSQ7CBL CSQ7CBU
Fix information
Fixed component name
WMQ Z/OS V7
Fixed component ID
5655R3600
Applicable component levels
Fix is available
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Document Information
Modified date:
30 May 2014