APAR status
Closed as program error.
Error description
If queue manager startup has an outstanding tape mount for a log archive, START CHINIT does not complete and the listeners do not start until the outstanding tape mount is satisfied or cancelled. This is similar to the situation in APAR PH23328. Recreate scenario: 1. Use CSQ6ARVP or SET ARCHIVE to specify a tape UNIT 2. Disable tape activity to make tapes unavailable 3. Recall some migrated datasets to force HSM to be very busy 4. Force an archive with the ARCHIVE LOG command 5. Verify that the offload task is busy by using the DISPLAY LOG command: CSQJ370I !CSQ1 LOG status report ... Copy %Full zHyperWrite Encrypted DSName 1 1 NO YES hlq.LOGCOPY1.DS04 2 1 NO YES hlq.LOGCOPY2.DS04 Restarted at <date, time> using RBA=<rba value> Latest RBA=<rba value> Offload task is BUSY, allocating archive data set Full logs to offload - 2 of 12 6. Cancel the queue manager 7. Restart the queue manager IEF244I CSQ1MSTR CSQ1MSTR - UNABLE TO ALLOCATE 1 UNIT(S) AT LEAST 1 OFFLINE UNIT(S) NEEDED. IEF877E CSQ1MSTR NEEDS 1 UNIT(S) FOR CSQ1MSTR SYS00013 LIBRARY: <libaray> LIBRARY STATUS: ONLINE OFFLINE ... IEF878I END OF IEF877E FOR CSQ1MSTR CSQ1MSTR SYS00013 *nnnn IEF238D CSQ1MSTR - REPLY DEVICE NAME OR 'CANCEL'. CSQY022I !CSQ1 QUEUE MANAGER INITIALIZATION COMPLETE The queue manager completes initialization, but the CHIN does not. A dump was captured at the time of the hang. IPCS ANALYZE RESOURCE shows that one TCB for the CSQ1MSTR job holds MAJOR=SYSZTIOT, and a different TCB for the MQ command processor requires it. The waiting ENQ is due to an OPEN for the CSQOUT2 DD by CSQNRRWO. Additional keywords: CHIN start up wait hang hung GRS contention
Local fix
Resolve the tape mount request if possible
Problem summary
**************************************************************** * USERS AFFECTED: All users of IBM MQ for z/OS Version 9 * * Release 2 Modification 0. * **************************************************************** * PROBLEM DESCRIPTION: SYSZTIOT contention causes the command * * server to hang during channel initiator * * startup. * **************************************************************** During startup a log offload is outstanding so CSQJOFF1 is called to offload the logs. The required tape drive is offline so the offload task is suspended in DYNALLOC processing waiting for the device, while holding the SYSZTIOT ENQ. When the channel initiator is started from CSQINP2, the startup completion message is written to the CSQOUT2 DD, however as this can occur after the initialisation server has finished processing all commands in CSQINP2, the message is written by the command server, which will open a new DCB for CSQOUT2. This ?OPEN hangs because it requires the SYSZTIOT ENQ, resulting in the command server hanging until the ENQ is available.
Problem conclusion
Queue manager startup processing is changed to cache the DCB for CSQOUT2, allowing 'late' responses to be written to this DD without requiring the SYSZTIOT ENQ.
Temporary fix
Comments
APAR Information
APAR number
PH38891
Reported component name
IBM MQ Z/OS V9
Reported component ID
5655MQ900
Reported release
202
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2021-07-12
Closed date
2022-04-14
Last modified date
2022-06-01
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI80142
Modules/Macros
CSQNINE1 CSQNINS CSQNRRWO
Fix information
Fixed component name
IBM MQ Z/OS V9
Fixed component ID
5655MQ900
Applicable component levels
[{"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"202","Line of Business":{"code":"LOB45","label":"Automation"}}]
Document Information
Modified date:
06 July 2022