Fixes are available
APAR status
Closed as program error.
Error description
Errors AMQ9511 and AMQ9448 are logged along with FFST regarding ProbeID: RM220005 and Probe Type: MSGAMQ9511 given by one or more slave repmans due to inconsistencies between CPUs regarding subscriptions in number and referenced object as well as expiration time. When multiple slaves are affected, in consequence the problem described in IT24388 may occur. This is a generic description of a multi root cause error scenario, please also check APARs about other problems identified: IT25665, IT25666, IT25669, IT25671. This APAR is about a general problem with the consistency of cluster cache maintenance, due to relying for multiple decisions on current usage state of object records in the cache.
Local fix
N/A
Problem summary
The information if a record is currently used by the queue manager is kept in shared memory, which is local for each CPU on NonStop. The maintenance operation on master were relying such decisions on the local cache state, not taking into account usage of entries on other CPUs. In consequence there have been problems due to missing subscriptions and cache inconsistencies between CPUs.
Problem conclusion
- Code was added to perform a maintenance prepare phase querying slave instances, to lock their cache and provide information about records currently in use. Maintenance was changed to also respect usage information from slaves, when ever decisions based on object usage are taken. Additionally each decision is recorded in the metadata. which is provided to the slaves along with the request to process, to ensure decisions being consistent for all cache instances. To guarantee correctness, slaves will hold lock of cluster cache until completing maintenance.
Temporary fix
Comments
APAR Information
APAR number
IT25666
Reported component name
WEBS MQ NSS ITA
Reported component ID
5724A3902
Reported release
531
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-07-12
Closed date
2018-07-13
Last modified date
2018-07-13
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
Fix information
Fixed component name
WEBS MQ NSS ITA
Fixed component ID
5724A3902
Applicable component levels
R531 PSY
UP
[{"Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSFKSJ","label":"WebSphere MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"5.3.1"}]
Document Information
Modified date:
28 September 2021