IBM Support

IT35809: MQ MFT resource monitor runs on multiple threads at the same time after its config

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APAR status

  • Closed as program error.

Error description

  • A resource monitor has been defined on an MQ Managed File
    Transfer (MFT) agent, and has been configured to monitor a
    source directory. The configuration of the monitor is updated
    using the fteCreateMonitor command, specifying the -f parameter.
    After this happens:
    
    - The agent starts receiving multiple transfer requests for the
    same transfer items, instead of just one.
    - The agent's resource monitor event log (resmonevent0.log)
    shows that the monitor is running on different threads within
    the agent at the same time.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    This issue affects users of IBM MQ Managed File Transfer who are
    using resource monitors, and want to update the configuration of
    those monitors.
    
    
    Platforms affected:
    MultiPlatform
    
    ****************************************************************
    PROBLEM DESCRIPTION:
    IBM MQ 9.1.5.0 Managed File Transfer changed the way in which
    resource monitor threads ran. Prior to MQ 9.1.5.0, resource
    monitor threads ran as Java TimerTask - this meant that if a
    monitor's poll took took longer than its specified poll
    interval, the next poll would start as soon as the previous one
    had finished with no gap in between. In MQ 9.1.5.0, this was
    changed so that monitor threads were started using the Java
    ScheduledExecutorService. As a result of this change, once a
    monitor thread had completed its poll, it would wait for the
    specified poll interval before starting the next one.
    
    When a resource monitor's configuration changed, either by
    running the fteCreateMonitor command specifying the -f parameter
    or by using the MQ Explorer Managed File Transfer plugin, the
    agent didn't stop the current resource monitor thread that had
    been started by the ScheduledExecutorService. As a result, there
    were multiple threads within the agent running the same resource
    monitor. The number of resource monitor threads would be equal
    to the number of times the monitor's configuration had been
    changed since the agent hosting the monitor had restarted.
    
    When this issue occurred, an agent's resource monitor event log
    (resmonevent0.log) would contain multiple entries for a single
    resource monitor, where the entries were generated by different
    threads, as shown in the example below:
    
    [25/01/2021 13:05:57:664 IST] 00000073  TESTM
    Start Poll     New poll cycle started
    [25/01/2021 13:05:57:696 IST] 00000073  TESTM               End
    Poll      Poll cycle completed in 32 milliseconds. Trigger items
    matched [ 0 ]
    [25/01/2021 13:06:16:117 IST] 00000082  TESTM
    Start Poll     New poll cycle started
    [25/01/2021 13:06:16:164 IST] 00000082  TESTM               End
    Poll      Poll cycle completed in 47 milliseconds. Trigger items
    matched [ 0 ]
    [25/01/2021 13:06:27:711 IST] 00000073  TESTM
    Start Poll     New poll cycle started
    [25/01/2021 13:06:27:742 IST] 00000073  TESTM               End
    Poll      Poll cycle completed in 31 milliseconds. Trigger items
    matched [ 0 ]
    [25/01/2021 13:06:46:180 IST] 00000082  TESTM
    Start Poll     New poll cycle started
    [25/01/2021 13:06:46:242 IST] 00000082  TESTM               End
    Poll      Poll cycle completed in 62 milliseconds. Trigger items
    matched [ 0 ]
    

Problem conclusion

  • To resolve this issue, MQ Managed File Transfer has been updated
    to ensure that if a resource monitor's configuration has been
    updated, using:
    
    - Either by running the fteCreateMonitor command specifying the
    -f parameter
    - Or by using the MQ Explorer Managed File Transfer plugin
    
    then the existing resource monitor thread is stopped before the
    new thread is started.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
    Version    Maintenance Level
    v9.2 LTS   9.2.0.2
    v9.x CD    9.2.2
    
    The latest available MQ 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

    IT35809

  • Reported component name

    IBM MQ MFT V9.1

  • Reported component ID

    5724H7272

  • Reported release

    915

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2021-02-05

  • Closed date

    2021-02-10

  • Last modified date

    2021-07-02

  • 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 MFT V9.1

  • Fixed component ID

    5724H7272

Applicable component levels

[{"Type":"MASTER","Line of Business":{"code":"LOB36","label":"IBM Automation"},"Business Unit":{"code":"BU053","label":"Cloud & Data Platform"},"Product":{"code":"SSYHRD","label":"IBM MQ"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"All Versions"}]

Document Information

Modified date:
03 July 2021