IT19521: MQ V8 - TELEMETRY CHANNEL - FDC WITH PROBEID XR051002 FILLING THE FILE SYSTEM.

APAR status

• Closed as program error.

Error description

• Customer observes 2 issues:
  
  - A large number of FDCs being generated by the MQ Telemetry
  channel, with probeID XR051002, and Exception cause
  
      "java.lang.Exception: mqcd<mqsc>:json at
  com.ibm.mq.MQXRService.MQTransmitQueueMessage
  	parseRfh2(MQTransmitQueueMessage.java:798)"
  
  - A build up of messages on the SYSTEM.MQTT.TRANSMIT.QUEUE and
  very slow performances.
  

Local fix

• n/a
  

Problem summary

• ****************************************************************
  USERS AFFECTED:
  This issue affects users of:
  
  - The MQ V8 Telemetry channel.
  - The MQ V9 Telemetry channel.
  
  who have:
  
  - MQ TT clients which publish messages on a topic, where the
  messages have the "Msd" field within the <mcd> folder within the
  MQRFH2 header set to a value other than the ones shown below:
  
      - jms_bytes
      - jms_map
      - jms_none
      - jms_object
      - jms_stream
      - jms_text
      - mrm
      - xmlnsc
      - xmlns
      - xml
      - mime
      - idoc
      - none
  
  - And MQ TT clients that subscribe to the same topic.
  
  
  Platforms affected:
  MultiPlatform
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  When the MQ Telemetry channel is given a message to forward on
  to an MQTT subscriber, it looks at the Msd field within the
  <mcd> folder in the MQRFH2 header for the message to determine
  how to treat the message payload. The MQ Telemetry channel
  expects this field to have one of the following values:
  
  - jms_bytes
  - jms_map
  - jms_none
  - jms_object
  - jms_stream
  - jms_text
  - mrm
  - xmlnsc
  - xmlns
  - xml
  - mime
  - idoc
  - none
  
  If the Msd field was set to a different value, then the MQ
  Telemetry channel would treat the message payload as bytes when
  forwarding it on to an MQ TT subscriber. However, the channel
  would also generate an FDC containing probe identifier XR051002.
  
  If every message that was processed by the MQ Telemetry channel
  had the Msd field set to an unexpected value, then it would
  generate an FDC for every message. As well as filling up the
  file system on the machine where the queue manager was running,
  this also affected the performance of the MQ Telemetry channel
  (generating an FDC is quite a performance intensive operation)
  which resulted in messages building up on the system queue
  SYSTEM.MQTT.TRANSMIT.QUEUE used by the channel.
  

Problem conclusion

• The MQ Telemetry channel has been updated so that it does not
  generate an FDC if it is asked to process a message where the
  Msd field within the <msd>folder within the MQRFH2 header of a
  message is set to an unexpected value.
  
  FDCs should only be generated for errors that are severe, and
  potentially unrecoverable, and they usually indicate either a
  configuration issue or an internal problem with an MQ component.
  In this case, the MQ Telemetry channel has been asked to process
  a message which has an unexpected format. The channel is able to
  process this message, so the error is not unrecoverable, and
  there is no internal MQ issue or configuration issue, which
  means that an FDC is not required here.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v8.0       8.0.0.7
  v9.0 LTS   9.0.0.2
  
  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 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