APAR status
Closed as program error.
Error description
When using MQ Explorer 8.0 with many sets of queue managers in the left navigation panel, some of these sets fail to expand fully: some queue managers are shown, but other queue managers in the set are missing.
Local fix
Problem summary
**************************************************************** USERS AFFECTED: This issue affects users of the IBM MQ Explorer V8 who use Queue Manager Sets, and administer remote queue managers via an intermediate queue manager. Platforms affected: Windows, Linux on x86, Linux on x86-64 **************************************************************** PROBLEM DESCRIPTION: When the IBM MQ Explorer starts up, a number of internal threads are created which look at all of the queue managers that the user interface has been configured to monitor, and register them with an internal data model. There is one internal thread for each queue manager that has been defined in the user interface. As part of the registration process, the internal threads associate the queue manager that they are registering with any Queue Manager Sets that the queue manager belongs to. While this processing was taking place, it was possible for a deadlock situation to occur between two internal threads which prevented any new queue managers from being registered with the IBM MQ Explorer. As a result of this, any queue managers that were successfully registered before the deadlock occurred would appear in any Queue Manager Sets that they had been assigned to. However, those queue managers that were still being registered at the time of the deadlock would not appear in any Queue Manager Sets. A Javacore taken when the deadlock occurred showed that the following two threads were involved: Thread 1: --------------------------- "WebSphere MQ creating : QM1" Blocked on: java/lang/Object@0xDCFFF8 Owned by: "WebSphere MQ creating : QM2" Java callstack: at com/ibm/mq/explorer/core/internal/utils/ CoreServices.sameTreeNameExists(CoreServices.java:2131) (entered lock: com/ibm/mq/explorer/core/internal/utils/CoreServices@0xD34190) at com/ibm/mq/explorer/core/internal/objects/ DmQueueManager.getTreeName(DmQueueManager.java:1530(Compiled Code)) at com/ibm/mq/explorer/core/internal/objects/ DmQueueManager.(DmQueueManager.java:516) at com/ibm/mq/explorer/core/internal/objects/ CreateDmQueueManager.run(CreateDmQueueManager.java:160) (entered lock: java/lang/Object@0x471D30) Thread 2: --------------------------- "WebSphere MQ creating : QM2" Blocked on: com/ibm/mq/explorer/core/internal/utils/CoreServices@0xD34190 Owned by: "WebSphere MQ creating : QM1" Java callstack: at com/ibm/mq/explorer/core/internal/utils/ CoreServices.getMatchingQueueManager(CoreServices.java:1625) (entered lock: java/lang/Object@0xDCFFF8) at com/ibm/mq/explorer/core/internal/objects/DmQueueManager. connectUsingVia(DmQueueManager.java:1096) at com/ibm/mq/explorer/core/internal/objects/ DmQueueManager.connectToQueueManager(DmQueueManager.java:785) at com/ibm/mq/explorer/core/internal/objects/ DmQueueManager.init(DmQueueManager.java:612) at com/ibm/mq/explorer/core/internal/objects/ DmQueueManager.connectSynchronously(DmQueueManager.java:2289) at com/ibm/mq/explorer/core/internal/objects/ CreateDmQueueManager.run(CreateDmQueueManager.java:218)
Problem conclusion
The internal locking model used by the IBM MQ Explorer has been updated to ensure that the internal threads used to register queue managers with the internal data model hold all of the required locks before starting with the registration process. This ensures that the deadlock reported in the APAR no longer occurs. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v8.0 8.0.0.4 The latest available maintenance can be obtained from 'WebSphere MQ Recommended Fixes' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006037 If the maintenance level is not yet available information on its planned availability can be found in 'WebSphere MQ Planned Maintenance Release Dates' http://www-1.ibm.com/support/docview.wss?rs=171&uid=swg27006309 ---------------------------------------------------------------
Temporary fix
Comments
APAR Information
APAR number
IT09497
Reported component name
WMQ BASE MULTIP
Reported component ID
5724H7251
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt
Submitted date
2015-06-17
Closed date
2015-09-29
Last modified date
2015-09-29
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
WMQ BASE MULTIP
Fixed component ID
5724H7251
Applicable component levels
R800 PSY
UP
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Document Information
Modified date:
29 September 2015