A fix is available
APAR status
Closed as program error.
Error description
Queue Alias deletions are not being being propagated across cluster . Additional keywords: Although the MQOPEN will work, the message may go to the Dead Letter Queue (DLQ) on a remote queue manager that once hosted a deleted cluster queue or queue manager alias. The DLH Reason might be: 2085 0x00000825 MQRC_UNKNOWN_OBJECT_NAME 2082 0x00000822 MQRC_UNKNOWN_ALIAS_BASE_Q 2087 0x00000827 MQRC_UNKNOWN_REMOTE_Q_MGR . QALIAS * Additional information to be aware of after applying this APAR: . This APAR also addresses an clustering issue where QALIAS deletions were not correctly propagated around the cluster. This led to situations where messages could be put to a clustered queue that no longer exists, resulting in the messages being put to the DLQ instead. . Part of the fix for that situation involves MQ temporarily creating and then deleting new clustering subscriptions to ensure we reach the correct final state. These temporary subscriptions cause more messages to be created on SYSTEM.CLUSTER.* queues (higher curdepth) and cause more storage usage within the cluster cache. When these subscriptions are deleted, the storage they use is not immediately released. It is released when clustering maintenance processing runs around once per hour. . After this APAR is applied, if there are a large number of cluster objects to resolve, and if CLCACHE=STATIC, the following message can result: CSQX460E :MQP1 CSQXREPO Cluster cache is full In that situation use CLCACHE=DYNAMIC if possible.
Local fix
N/A
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 0 Modification 0 and Release 1 * * Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: It is possible when a Queue or QMGR * * Cluster Cache record is used and has * * not been used for a long period of * * time that the process will attempt * * to use the object 'as is' without * * first updating the object which can * * lead to unwanted behaviour. * **************************************************************** After the subscriptions for a Cluster Cache Object (either a Queue or QMGR object) expire the object itself will remain in the cluster cache for a grace period. It is during this time that if some change happens to the actual object that the cluster cache record relates to then the cluster cache record will not be updated to reflect the change. This is because there are no subscriptions for that object anymore. For Queue objects this poses a problem if the Queue has been deleted in this time window as any MQPUT's to the queue via the cluster member hosting the active Queue Cluster cache record will not fail for RC=2085 MQRC_UNKNOWN_OBJECT_NAME as may be expected and the message will end up on the Dead Letter Queue. Similar behaviour can also be seen for QMGR cluster cache objects as well, for example if a QMGR is removed from a cluster in the discussed time window.
Problem conclusion
Additional checks have been introduced so that on an MQOPEN the Cluster Cache object that is being used is checked to see if any subscriptions exist for the object before using it. If there are none then new ones will be created. This will ensure that the cluster cache object being used is up to date before it is being used. The following page in the IBM MQ 9.0.x Knowledge Center is updated: Home ->IBM MQ 9.0.x ->IBM MQ ->Reference ->Messages ->IBM MQ for z/OS messages, completion, and reason codes ->Messages for IBM MQ for z/OS https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.0.0/com. ibm.mq.ref.doc/csq_m.htm The following is added: CSQM580I csect-name CLUSTER OBJECT NAME object-name LOCATED AT QMID qmid IS RESOLVED USING OLD CACHED INFORMATION. Severity 0 Explanation The cluster object referenced has been resolved using old cached information. System action Processing continues. System programmer response None. ================================================================ The following page in the IBM MQ 9.1.x Knowledge Center is updated: Home ->IBM MQ 9.0.x ->IBM MQ ->Reference ->Messages ->IBM MQ for z/OS messages, completion, and reason codes ->Messages for IBM MQ for z/OS https://www.ibm.com/support/knowledgecenter/en/SSFKSJ_9.1.0/com. ibm.mq.ref.doc/csq_m.htm The following is added: CSQM580I csect-name CLUSTER OBJECT NAME object-name LOCATED AT QMID qmid IS RESOLVED USING OLD CACHED INFORMATION. Severity 0 Explanation The cluster object referenced has been resolved using old cached information. System action Processing continues. System programmer response None.
Temporary fix
Comments
APAR Information
APAR number
PH04894
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
000
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-11-05
Closed date
2019-04-25
Last modified date
2021-05-06
APAR is sysrouted FROM one or more of the following:
PH00904
APAR is sysrouted TO one or more of the following:
UI62677 UI62678 UI62679 UI62680 UI62681 UI62682 UI62683 UI62684
UI62685 UI62686 UI62687 UI62688
Modules/Macros
CSQFMDIC CSQFMDIE CSQFMDIF CSQFMDIK CSQFMDIU CSQFMTXC CSQFMTXE CSQFMTXF CSQFMTXK CSQFMTXU CSQMZLOO
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
R000 PSY UI63982
UP19/07/24 P F907
R001 PSY UI63984
UP19/07/24 P F907
R002 PSY UI63983
UP19/07/24 P F907
R003 PSY UI63985
UP19/07/24 P F907
R004 PSY UI63986
UP19/07/24 P F907
R005 PSY UI63987
UP19/07/24 P F907
R100 PSY UI63988
UP19/07/24 P F907
R101 PSY UI63991
UP19/07/24 P F907
R102 PSY UI63993
UP19/07/24 P F907
R103 PSY UI63992
UP19/07/24 P F907
R104 PSY UI63989
UP19/07/24 P F907
R105 PSY UI63990
UP19/07/24 P F907
Fix is available
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Document Information
Modified date:
07 May 2021