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IT35701: Messages left on source queue at the end of a successful message-to-file transfer.

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APAR status

  • Closed as program error.

Error description

  • An MQ Managed File Transfer agent is acting as the source agent
for a message-to-file transfer when it is stopped unexpectedly.

When the agent restarts, the managed transfer resumes and
completes successfully. However, the message that was included
in the managed transfer is not deleted from the source queue
when the transfer finishes.

An MQ Managed File Transfer agent trace covering the time when
the agent restarts shows that it encountered a
NullPointerException while processing the source disposition for
the message-to-file transfer. Here is an extract from a trace
file that shows this:

-----------------------------------------------
[26/02/21 00:04:47.199.5Q]  00000016  @6fc809df
c.i.w.t.frame.impl.TransferFrameSenderImpl
       ----+----+----+  X  deleteOpenFile
[26/02/21 00:04:47.199.5Q]  00000016 <null>
[java.lang.NullPointerException] at:
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.io.queue.FTEQueueChannel.openForRead(FTEQueueChan
nel.java:336)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.io.queue.FTEQueueFilterChannel.openForRead(FTEQue
ueFilterChannel.java:135)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.frame.impl.TransferFrameSenderImpl.openA
ndLockFile(TransferFrameSenderImpl.java:1454)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.frame.impl.TransferFrameSenderImpl.delet
eOpenFile(TransferFrameSenderImpl.java:1846)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderRunnable.deleteFile(T
ransferSenderRunnable.java:1562)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderImpl.deleteFile(Trans
ferSenderImpl.java:382)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEMutableSenderState.processSour
ceDisposition(FTEMutableSenderState.java:1155)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEMutableSenderState.addProgress
Audit(FTEMutableSenderState.java:854)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEStateStoreImpl.publishProgress
Audit(FTEStateStoreImpl.java:1827)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEStateStoreImpl.publishProgress
Audit(FTEStateStoreImpl.java:1625)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderRunnable.generateAudi
tInformation(TransferSenderRunnable.java:1342)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderRunnable.auditComplet
e(TransferSenderRunnable.java:1499)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderImpl.onComplete(Trans
ferSenderImpl.java:353)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEStateStoreImpl.sendForgetToFar
End(FTEStateStoreImpl.java:1411)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.FTECommandHandlerStateStoreImpl.p
rocessInternalCommand(FTECommandHandlerStateStoreImpl.java:765)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.MessageHandlerImpl.internalMessag
eHandler(MessageHandlerImpl.java:434)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.MessageHandlerImpl.processCommand
(MessageHandlerImpl.java:165)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.FTECommandHandlerWorkerThread.pro
cessCommand(FTECommandHandlerWorkerThread.java:282)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.FTECommandHandlerWorkerThread.run
(FTECommandHandlerWorkerThread.java:173)
[26/02/21 00:04:47.199.5Q]  00000016
java.lang.Thread.run(Thread.java:822)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.thread.FTEThread.run(FTEThread.java:70)
-----------------------------------------------

Local fix

  • 



Problem summary


    

  • ****************************************************************
USERS AFFECTED:
This issue affects users of MQ Managed File Transfer, who have
agents that participate in message-to-file transfers.


Platforms affected:
MultiPlatform

****************************************************************
PROBLEM DESCRIPTION:
If an MQ Managed File Transfer agent is acting as the source
agent for a message-to-file transfer, it will:

- Browse the messages on the source queue during the managed
transfer.
- And only remove the messages from the queue once the managed
transfer has completed successfully.

In order to do this, the internal TransferCompletedWorker thread
(the thread within the agent that handles the source disposition
for managed transfers) will use an internal FTEQueueChannel
object to make a number of MQGET API calls to remove the
messages from the queue.


Now, if the source agent was stopped:

- After it had sent the message data for a message-to-file
transfer to the destination agent.
- And before it had received a reply from the destination agent
indicating that the message data had been received successfully
and the destination file had been written.

then when the source agent restarted, it would:

- Pick up the reply from the destination agent.
- Perform some processing on the managed transfer, to move it
into a "Completed" state.
- And then put a message onto an internal Java queue, to inform
the TransferCompletedWorker thread that the source disposition
could now be processed for the managed transfer.

When the TransferCompletedWorker thread picked up the message
and started to process the source disposition, it found that
there wasn't an existing FTEQueueChannel for the managed
transfer (as the agent hadn't actually read any messages from
the source queue for the managed transfer since it had been
restarted). However, when it tried to recreate the
FTEQueueChannel and reopen the queue, a NullPointerException
occurred. The thread caught the NullPointerException internally,
swallowed it up and then skipped over the logic to delete the
messages from the source queue.

Here is an extract from an MQ Managed File Transfer trace which
shows the NullPointerException:

-----------------------------------------------
[26/02/21 00:04:47.199.5Q]  00000016  @6fc809df
c.i.w.t.frame.impl.TransferFrameSenderImpl
       ----+----+----+  X  deleteOpenFile
[26/02/21 00:04:47.199.5Q]  00000016 <null>
[java.lang.NullPointerException] at:
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.io.queue.FTEQueueChannel.openForRead(FTEQueueChan
nel.java:336)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.io.queue.FTEQueueFilterChannel.openForRead(FTEQue
ueFilterChannel.java:135)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.frame.impl.TransferFrameSenderImpl.openA
ndLockFile(TransferFrameSenderImpl.java:1454)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.frame.impl.TransferFrameSenderImpl.delet
eOpenFile(TransferFrameSenderImpl.java:1846)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderRunnable.deleteFile(T
ransferSenderRunnable.java:1562)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderImpl.deleteFile(Trans
ferSenderImpl.java:382)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEMutableSenderState.processSour
ceDisposition(FTEMutableSenderState.java:1155)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEMutableSenderState.addProgress
Audit(FTEMutableSenderState.java:854)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEStateStoreImpl.publishProgress
Audit(FTEStateStoreImpl.java:1827)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEStateStoreImpl.publishProgress
Audit(FTEStateStoreImpl.java:1625)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderRunnable.generateAudi
tInformation(TransferSenderRunnable.java:1342)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderRunnable.auditComplet
e(TransferSenderRunnable.java:1499)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.transfer.impl.TransferSenderImpl.onComplete(Trans
ferSenderImpl.java:353)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.statestore.impl.FTEStateStoreImpl.sendForgetToFar
End(FTEStateStoreImpl.java:1411)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.FTECommandHandlerStateStoreImpl.p
rocessInternalCommand(FTECommandHandlerStateStoreImpl.java:765)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.MessageHandlerImpl.internalMessag
eHandler(MessageHandlerImpl.java:434)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.MessageHandlerImpl.processCommand
(MessageHandlerImpl.java:165)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.FTECommandHandlerWorkerThread.pro
cessCommand(FTECommandHandlerWorkerThread.java:282)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.cmdhandler.impl.FTECommandHandlerWorkerThread.run
(FTECommandHandlerWorkerThread.java:173)
[26/02/21 00:04:47.199.5Q]  00000016
java.lang.Thread.run(Thread.java:822)
[26/02/21 00:04:47.199.5Q]  00000016
com.ibm.wmqfte.thread.FTEThread.run(FTEThread.java:70)
[26/02/21 00:04:47.199.5Q]  00000016 Object ClassLoader = null
-----------------------------------------------

    



Problem conclusion


    

  • To resolve this issue, MQ Managed File Transfer agents have been
updated so that if:

- The internal TransferCompletedWorker thread is processing the
source disposition for a message-to-file transfer.
- And it finds that there isn't an existing FTEQueueChannel for
the managed transfer.

then it will successfully create one, and then use it to open
the source queue and delete the messages from it.

---------------------------------------------------------------
The fix is targeted for delivery in the following PTFs:

Version    Maintenance Level
v9.1 LTS   9.1.0.9
v9.2 LTS   9.2.0.3
v9.x CD    9.2.3

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
    IT35701
    • 

  • Reported component name
    MQ BASE V9.2
    • 

  • Reported component ID
    5724H7281
    • 

  • Reported release
    920
    • 

  • Status
    CLOSED  PER
    • 

  • PE
    NoPE
    • 

  • HIPER
    NoHIPER
    • 

  • Special Attention
    NoSpecatt / Xsystem
    • 

  • Submitted date
    2021-01-26
    • 

  • Closed date
    2021-03-17
    • 

  • Last modified date
    2021-04-08
    • 





    

  • 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
    MQ BASE V9.2
    • 

  • Fixed component ID
    5724H7281
    • 



Applicable component levels


    








      
              
                            

              

              [{"Line of Business":{"code":"LOB45","label":"Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"920"}]
              

                          

          
 
        

      

    

      

        

          

            
Document Information


            

            


                        

            Modified date:
            

            09 April 2021
            

            
                      

        


        

        


      

    

  



    

  

  
    
            

          
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