APAR status
Closed as program error.
Error description
The AMQP channel ends with an error in the log: AMQCO2001E: An error (probe: XR014005) occurred and a Failure Data Capture (FDC) file has been written to file '/var/mqm/errors/AMQP0.FDC'. AMQCO1006I: Channel 'SYSTEM.DEF.AMQP' has stopped and an FDC generated with details: Probe Id :- XR014005 java.lang.NullPointerException at com.ibm.mq.MQXRService.MQConnection.jmqiGet(MQConnection.java:10 57) at com.ibm.mq.MQXRService.WorkerContext.browseMessageFromTransmitQu eue(WorkerContext.java:563) at com.ibm.mq.MQXRService.OutboundInFlightMessage.getMqTransmitQueu eMessage(OutboundInFlightMessage.java:180) at com.ibm.mq.MQXRService.AMQPSubscriptionWrapper.captureBufferedMe ssages(AMQPSubscriptionWrapper.java:327) at com.ibm.mq.MQXRService.AMQPServerSessionV10.sendMessageBacklog(A MQPServerSessionV10.java:2024) at com.ibm.mq.MQXRService.MQTTServerSession.prepareAsynchronousWork (MQTTServerSession.java:912) at com.ibm.mq.MQXRService.AMQPServerWireContext.prepareAsynchronous Work(AMQPServerWireContext.java:198) at com.ibm.mq.communications.NonBlockingWorker.synchronousWorkCompl eted(NonBlockingWorker.java:615) at com.ibm.mq.communications.NonBlockingWorker.run(NonBlockingWorke r.java:422) at java.lang.Thread.run(Thread.java:809)
Local fix
Problem summary
**************************************************************** USERS AFFECTED: This issue affects users of the IBM MQ AMQP service, where the service experiences very high JVM heap utilisation while messages are being sent to subscribing clients. Platforms affected: MultiPlatform **************************************************************** PROBLEM DESCRIPTION: When a heavily-loaded v8.0 or v9.0 AMQP service approaches the limit of available heap memory, it can preemptively close some client connections and associated internal objects in order to free up space. This avoids it from hitting a serious runtime error (such as a java.lang.OutOfMemoryError) that could result in the AMQP service ending unexpectedly. There was a small timing window which meant that if the internal objects were closed at the same time as the AMQP service was getting a message from the transmit queue to send to an AMQP client, then a method was called on a null object. This resulted in a NullPointerException to be generated, which caused the AMQP service to stop unexpectedly.
Problem conclusion
Additional checks have been added to the IBM MQ AMQP service to ensure that internal calls are not made on objects that could be null at any point. These checks prevent NullPointerExceptions from occurring if client connections and internal objects are being closed to free up memory at the same time as messages for those clients are being retrieved from the queue manager. --------------------------------------------------------------- The fix is targeted for delivery in the following PTFs: Version Maintenance Level v8.0 8.0.0.13 v9.0 LTS 9.0.0.8 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
IT29370
Reported component name
IBM MQ BASE MP
Reported component ID
5724H7251
Reported release
800
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2019-06-07
Closed date
2019-08-07
Last modified date
2019-09-24
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
IBM MQ BASE MP
Fixed component ID
5724H7251
Applicable component levels
[{"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"8.0.0.0","Edition":"","Line of Business":{"code":"LOB45","label":"Automation"}}]
Document Information
Modified date:
24 September 2019