A fix is available
APAR status
Closed as program error.
Error description
High CPU consumption in module CSQLLPLM. It occurs when an application browses messages on the queue, and then closes the queue with the delete-purge option. The IS allocation page lock that browse processing obtained prior to the close of the queue is not released, causing the problem seen with high CPU in CSQLLPLM.
Local fix
n/a
Problem summary
**************************************************************** * USERS AFFECTED: * * All users of IBM MQ for z/OS Version 9 Release 0 * * Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: * * High CPU in load module CSQLLPLM due to a build up of * * allocation locks on pages used by dynamic queues. * **************************************************************** * RECOMMENDATION: * * none * **************************************************************** When browsing a dynamic queue, an application obtained an allocation lock on the pages currently under the browse cursor. When the application closed the queue it specified that the dynamic queue should be deleted (e.g. passing MQCO_DELETE_PURGE to MQCLOSE), and so CSQMCLS2 called CSQIDDEL to delete the queue. When this returned CSQMCLS2 called CSQIMBLR to release the locks under the browse cursor, however because the IVSA for the queue no longer existed CSQIMBLR could not determine if the queue was private or shared, and so skipped releasing the locks. Over time the number of allocation locks that had not been correctly released by a long running application can build up, leading to high CPU in CSQLLPLM while searching long chains of lock control blocks.
Problem conclusion
CSQIMBLR is changed to correctly release the allocation locks when called as part of a close operation that also deletes the dynamic queue.
Temporary fix
Comments
APAR Information
APAR number
PI68940
Reported component name
MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
000
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-09-09
Closed date
2016-09-26
Last modified date
2017-05-19
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI41081
Modules/Macros
CSQIMBLR CSQMCLS2
Fix information
Fixed component name
MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
R000 PSY UI41081
UP16/10/14 P F610
Fix is available
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Document Information
Modified date:
19 May 2017