IBM Support

IZ19168: PROBE RM400001 FFST USING PIPELINED CHANNELS AT 6.0.2.3

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APAR status

  • Closed as program error.

Error description

  • A customer running WMQ 6.0.2.3 using pipelined channels
    intermittently experienced FFST probe RM400001 from cccFreeMem
    in their channel processes.
    
    The error often occurred just after a channel ended with
    AMQ9545 (disconnect interval expired), although it can also
    occur at other times.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Only users who use pipelined channels (qm.ini setting
    PipeLineLength=2 or equivalent). Those channels which use
    message compression are more likely to encounter this issue due
    to the additional buffer management, although any pipelined
    channel can be affected.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    The WMQ channels code keeps track of various memory buffers used
    for reading data from the network and processing messages. The
    state information used to track memory usage in pipelined
    channels lacked sufficient locking to ensure reliable tracking
    of the memory buffers.
    
    As a result, there were time windows in which it was possible
    for a pipelined channel thread pair to lose track of what
    buffers had been allocated and freed. This would result in a
    probe RM400001 FFST accompanied by a small memory leak.
    

Problem conclusion

  • The channel memory management code has been enhanced to ensure
    proper locking between pairs of pipelined channel threads.
    This is to ensure that memory usage is reliably tracked for
    each thread.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v6.0
    Platform           Fix Pack 6.0.2.5
    --------           --------------------
    Windows            U200292
    AIX                U815929
    HP-UX (PA-RISC)    U815636
    HP-UX (Itanium)    U815818
    Solaris (SPARC)    U815659
    Solaris (x86-64)   U815928
    iSeries            tbc
    Linux (x86)        U815767
    Linux (x86-64)     U815808
    Linux (zSeries)    U815805
    Linux (Power)      U815806
    Linux (s390x)      U815807
    
    The latest available maintenance can be obtained from
    Websphere MQ
    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

    IZ19168

  • Reported component name

    WMQ LIN X86 V6

  • Reported component ID

    5724H7204

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2008-04-02

  • Closed date

    2008-05-20

  • Last modified date

    2008-05-20

  • 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

    5724H7204

Applicable component levels

  • R600 PSY

       UP

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Document Information

Modified date:
20 May 2008