IT14568: .NET application generates failure data capture file due to incorrect response to API call

APAR status

• Closed as program error.

Error description

• An MQ .Net  application is not getting reply from an MQ API
  call,  and
  the application thread appears blocked.
  
  Failure Data Capture (FDC) files are generated  by client
  application around
  the time when the  application threads are waiting for a reply,
  similar to the following:
  
  | Probe Id          :- DN155001
  |
  | Application Name  :- MQM
  |
  | Component         :- MQFAP.MQBACK(MQHCONN,out MQLONG,out
  MQLONG)
  |
  | Process           :- 00000111
  |
  | Thread            :- 0000012
  |
  | Arith1            :- 149
  |
  | Comment2          :- Unexpected flow received during MQBACK
  |
  |
  |
  +---------------------------------------------------------------
  --------
  ------+
  MQM Function Stack
  MQDestination.Get(MQMessage,MQGetMessageOptions)
  MQDestination.Get(MQMessage,MQGetMessageOptions,int)
  MQFAP.MQBACK(MQHCONN,out MQLONG,out MQLONG)
  ManagedCommonServices.FFST(String,string,string,uint,uint,MQULON
  G,MQULONG,ushort)
  
  The FDC need not be cut always in MQFAP.MQBACK call, it can be
  generated from any MQAPI calls. Similarly application may not
  get reply for any MQAPI calls, it need not be MQGET always.
  
  Output from FFST summary:-
  
  DN>56001 MQFAP.MQDISC(Phconn,out int,out int)
  rrcE_COMMUNICATIONS_ERROR OK AMQ9213: A communications error for
  Unexpected flow  received during MQDISC call occurred.
  DN>61001 MQFAP.MQCLOSE(Hconn,Phobj,int,out int,ou
  rrcE_COMMUNICATIONS_ERROR OK AMQ9213: A communications error for
  Unexpected flow  received during MQCLOSE occurred.
  DN148001 MQFAP.MQPUT(MQHCONN,MQLONG,ref MQMessage
  rrcE_MQPUT_FAILED         OK AMQ9511: Messages cannot be put to
  a queue.
  DN155001 MQFAP.MQBACK(MQHCONN,out MQLONG,out MQLO
  rrcE_COMMUNICATIONS_ERROR OK AMQ9213: A communications error for
  Unexpected flow  received during MQBACK occurred.
  

Local fix

Problem summary

• ****************************************************************
  USERS AFFECTED:
  Users of Managed .Net client application
  
  
  Platforms affected:
  Windows
  
  ****************************************************************
  PROBLEM DESCRIPTION:
  A coding error within the synchronization logic of the MQ
  managed .NET client meant that a timing window existed where it
  was possible to deliver a response from the queue manager to a
  different thread, when multiple threads were perfoming MQ API
  calls concurrently. As the response was unexpected by the thread
  it was delivered to, this caused the FDC to be generated. The
  thread for which the response was intended continued to wait.
  

Problem conclusion

• MQ .Net Managed client logic has been updated to correct this
  synchronization.
  
  ---------------------------------------------------------------
  The fix is targeted for delivery in the following PTFs:
  
  Version    Maintenance Level
  v7.1       7.1.0.8
  v7.5       7.5.0.7
  v8.0       8.0.0.6
  v9.0 CD    9.0.1
  v9.0 LTS   9.0.0.1
  
  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

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