A fix is available
APAR status
Closed as program error.
Error description
The customer saw an increase of CPU consumption when using a shared queue. They applied the service parm for PM99242, which had no effect as the getters were using MQGMO_SET_SIGNAL rather than MQGMO_WAIT, and the function provided by PM99242 only caters for getters using MQGMO_WAIT. Additional Symptom(s) Search Keyword(s): performance
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 number of failed MQGET requests are seen in accounting * * class 3 SMF 116 records when multiple getters are waiting * * for messages on a shared queue. * * * * The getters are using MQGMO_SET_SIGNAL or they are client * * applications using SHARECNV>0 SVRCONN channels that the CHIN * * uses MQGMO_SET_SIGNAL internally. * **************************************************************** * RECOMMENDATION: * * N/A * **************************************************************** When 1 or more messages arrive on a shared queue all handles waiting for a message on that queue are posted by the list transition exits. If there are more handles than messages on the queue, some of the handles will not find a message and will reenter a getwait state. In certain environments it is possible to post a subset of the handles, reducing the number of additional get requests that are unable to successfully get a message.
Problem conclusion
When a service parameter is enabled, it will cause list transition processing to estimate the number of messages on a shared queue and post a smaller subset of handles to get those messages. This service parameter will now consider handles using MQGMO_SET_SIGNAL when determining whether a subset can be posted. The service parameter is not appropriate in all environments, and should only be enabled under direction of IBM support.
Temporary fix
Comments
APAR Information
APAR number
PI66242
Reported component name
MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
000
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2016-07-21
Closed date
2016-08-30
Last modified date
2016-11-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI40455
Modules/Macros
CSQMLTR0
Fix information
Fixed component name
MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
R000 PSY UI40455
UP16/11/02 P F610
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":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"9.0","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]
Document Information
Modified date:
02 November 2016