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

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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 number

    IT14568

  • Reported component name

    WMQ BASE MULTIP

  • Reported component ID

    5724H7251

  • Reported release

    800

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2016-04-01

  • Closed date

    2016-06-03

  • Last modified date

    2017-06-01

  • 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:
01 June 2017