A fix is available
APAR status
Closed as program error.
Error description
Customer used MDB applications on zWAS in 2-way sysplex environment. An MQ MDB thread was consuming a lot of CPU in zWAS controller region. In that environment, they changed an MDB target queue as get(disabled) from one member (SYSTEM S1). Later zWAS CR on SYSTEM S1 started to consume a lot of CPU. The high CPU situation continued after that. IBM c/t lab now confirmed that the incorrect posting of AC_SuspendECB with a postcode of 0 can lead to a high cpu loop, and had recreated a scenario where this loop occurred.
Local fix
n/a
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 1 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: 64 bit applications using asynchronous * * consumption (MQCB/MQCTL), for example * * MDBs,experience high cpu when the * * consumer is suspended or stopped. * **************************************************************** When a consumer task is posted to suspend and subsequently stop, an error occurs when posting the AC_ResumeECB causing it to be posted with an invalid postcode (either 0, or a residual suspend value). This postcode is unexpected, and causes the task requesting the consumer stops to loop.
Problem conclusion
CSQBMCS2 is changed to prevent the residual postcode overriding the expected postcode when an MDB is requested to stop, and to pass the postcode correctly to CSQBMCSD when running in 64bit environments.
Temporary fix
Comments
APAR Information
APAR number
PH14488
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
100
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-07-15
Closed date
2019-09-02
Last modified date
2019-10-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI65102
Modules/Macros
CSQBLB1 CSQBLB16 CSQBLB1X CSQBLB2 CSQBLB26 CSQBLB2X CSQBLB3 CSQBLB36 CSQBLB3X CSQBLB46 CSQBLB4X CSQBLB56 CSQBLB5X
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
R100 PSY UI65102
UP19/09/26 P F909 ¢
Fix is available
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Document Information
Modified date:
01 October 2019