A fix is available
APAR status
Closed as program error.
Error description
For a Message Broker application, where there is more than one resource manager involved in the RRS transaction (either two MQ qmgrs or MQ and another resource manager), code was added by PM75418, which can result in the committing thread going into wait loop which will never end.
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: After application of UK91874(V710) or * * UK91873(V701), when a WebSphere Message * * Broker application attempts to perform * * a MQCMIT for an RRS transaction to two * * or more resource managers, the MQCMIT * * may hang. * **************************************************************** * RECOMMENDATION: * **************************************************************** APAR PM75418 added additional serialization to ensure that RRS exits would wait until a context EB was no longer in use by any other tasks before being used. To accomplish this a flag is used to indicate whether the context EB is still in use. The exit waits until the EB is no longer in use before performing the commit, by waiting for the flag to be set. When Message Broker attempts to commit a transaction involving multiple resource managers, the RRS exit is driven on the same TCB as the MQCMIT, through the module CSQMCCMT. As such there is no need to wait for the EB. The checks implemented in PM75418 did not take this case into account. This results in the exit waiting indefinitely for CSQMCCMT to regain control and set the flag again.
Problem conclusion
The wait for this flag has been altered, to only occur if the flag wasn't set by this TCB. This ensures that the wait will not occur if it was set by CSQMCCMT. 010Y 100Y CSQARIB CSQMCLMT CSQMCTXE CSQMCTXS CSQ3AAES CSQ3AMT3 CSQ3RRSF CSQ3RRSI CSQ3RRSM CSQ3RRSR CSQ3RRSX CSQ3RRXF CSQ5CONN CSQ5MONR
Temporary fix
********* * HIPER * *********
Comments
APAR Information
APAR number
PM88417
Reported component name
WMQ Z/OS V7
Reported component ID
5655R3600
Reported release
010
Status
CLOSED PER
PE
YesPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2013-05-03
Closed date
2013-05-31
Last modified date
2013-08-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UK94741 UK94742
Modules/Macros
CSQARIB CSQMCLMT CSQMCTXE CSQMCTXS CSQ3AAES CSQ3AMT3 CSQ3RRSF CSQ3RRSI CSQ3RRSM CSQ3RRSR CSQ3RRSX CSQ3RRXF CSQ5CONN CSQ5MONR
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:
02 August 2013