A fix is available
APAR status
Closed as program error.
Error description
Customer complained that the chinit failed to initialize when offload failed due to unmounted tape. Once the outstanding tape mount was issued the CHINIT address completed initialization . In chin joblog: The CHIN joblog tells the CHINIT initialization started at 15:18:38 and over 8 mins the initialization completed as below: 15.18.38 S0088623 CSQX001I !MQZ2 CSQXJST Channel initiator starting 15.27.09 S0088623 +CSQX022I !MQZ2 CSQXSUPR Channel initiator initialization complete The delay is caused due to contention for the SYSZTIOT ENQ for the queue manager address space. The offload task has acquired this ENQ, presumably while doing DYNALLOC for the archive dataset, however it is suspended waiting on an ENQ held by DFHSM. While this is taking place, the pubsub component of the queue manager is started, and attempts to open the datasets in the CSQINPT DD, however as this operation also requires the SYSZTIOT ENQ, which is still held by offload processing, it is suspended. The chinit is also starting up, and because it is clustered, it has to wait for the queue manager pubsub component to start, so that it is able to process any cluster topic definitions - as pubsub startup is delayed, this results in the chinit startup also being delayed. Unfortunately contention for the SYSZTIOT has the potential to delay queue manager startup processing, however in the past we have been able to avoid some of the causes of such contention. Additional Symptom(s) Search Keyword(s):
Local fix
n/a
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 1 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: Channel initiator hangs during startup * * due to SYSZTIOT contention. * **************************************************************** While starting the queue manager detected an outstanding log offload, and issued SVC99 (DYNALLOC) to allocate an archive log dataset. Due to unavailable tape resources, the SVC call was delayed while holding the SYSZTIOT ENQ for the queue manager address space. When Topic Manager attempted to process the CSQINPT DD, it required this ENQ, and was suspended until it is available. This caused a delay in publish/subscribe initialisation. During chinit startup, the repository task detected there were clustered topics defined and suspended waiting for pubsub initialisation to complete.
Problem conclusion
CSQNINS and CSQNINPT are changed to open the CSQINPT/CSQOUTT DD prior to the point where log offloading is started, preventing any SYSZTIOT contention affecting the log offload from also delaying pubsub and channel initiator startup.
Temporary fix
Comments
APAR Information
APAR number
PI87162
Reported component name
MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
010
Status
CLOSED PER
PE
NoPE
HIPER
YesHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2017-09-12
Closed date
2019-06-28
Last modified date
2019-08-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI63994
Modules/Macros
CSQNINPT CSQNINS
Fix information
Fixed component name
MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
R100 PSY UI63994
UP19/07/23 P F907 ¢
Fix is available
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Document Information
Modified date:
01 August 2019