IBM Support

IY97558: Agent process does not return from a MQGET call for a period of time significantly larger than the time-out specified


You can track all active APARs for this component.


APAR status

  • Closed as program error.

Error description

  • In an agent with multiple applications servicing an individual
    queue, one particular application ends up in an MQGET call for
    an extended period of time when MQGMO_WAIT is specified. This
    results in the application seemingly hanging until the MQGET
    call returns.

Local fix

  • Not Applicable

Problem summary

  • ****************************************************************
    Anyone using MQ with multiple applications doing MQGET with
    MQGMO_WAIT specified on a queue.
    Platforms affected:
     All Distributed (iSeries, all Unix and Windows)
    The problem was caused by multiple agent threads competing for
    messages on a queue. A particular thread was consistently
    failing to retrieve a message from the queue prior to other
    threads obtaining the message. However, the timer used for the
    get with wait call was always being reset to 0 every time the
    thread was notified that a new message was ready for retrieval.
    As such, it was caught in an endless loop until it either
    successfully retrieved a message from the queue prior to other
    threads waiting, or a suitable amount of time longer than the
    wait interval passed without any new messages appearing on the

Problem conclusion

  • The solution was to avoid resetting the timer after each failed
    attempt to retrieve a message. As such, the wait interval was
    now able to expire and the MQGET could then return.
    The fix is targeted for delivery in the following PTFs:
    Platform           Fix Pack
    --------           --------------------
    Windows            U200279
    AIX                U811346
    HP-UX (PA-RISC)    U811630
    HP-UX (Itanium)    U811631
    Solaris (SPARC)    U811632
    Solaris (x86-64)   U811633
    iSeries            SI27288
    Linux (x86)        U811634
    Linux (x86-64)     U811635
    Linux (zSeries)    U811636
    Linux (Power)      U811637
    Linux (s390x)      U811638
    The latest available maintenance can be obtained from
    'WebSphere MQ Recommended Fixes'
    If the maintenance level is not yet available, information on
    its planned availability can be found in 'WebSphere MQ
    Planned Maintenance Release Dates'

Temporary fix


APAR Information

  • APAR number


  • Reported component name

    WMQ LIN X86 V6

  • Reported component ID


  • Reported release


  • Status


  • PE




  • Special Attention


  • Submitted date


  • Closed date


  • Last modified date


  • 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 LIN X86 V6

  • Fixed component ID


Applicable component levels

  • R600 PSY


[{"Business Unit":{"code":"BU048","label":"IBM Software"},"Product":{"code":"SSCPQ5M","label":"APAR"},"Component":"","ARM Category":[],"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"6.0","Edition":"","Line of Business":{"code":"","label":""}}]

Document Information

Modified date:
27 July 2007