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IC61638: An FDC is generated which fills up the entire disk.

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APAR status

  • Closed as program error.

Error description

  • An FDC is generated as a result of an MQ error. The FDC file
    continually grows and eventually fills up the disk
    space. The connection history section repeatedly loops dumping
    the same connection history data.
    

Local fix

Problem summary

  • ****************************************************************
    USERS AFFECTED:
    Potentially any users of WebSphere MQ experiencing a problem
    that results in an FDC and where the conditions documented in
    the Problem Summary are met.
    
    Platforms affected:
    All Distributed (iSeries, all Unix and Windows)
    ****************************************************************
    PROBLEM SUMMARY:
    A logic error within the connection history dumping code
    caused an infinite loop. The resultant
    FDC would grow to consume all space available until the
    process writing it is killed. The following conditions need to
    be met in order to cause the failure:
    
    1.) An FDC is generated which results in the dumping of the
    connection history information.
    
    2.) There have been sufficient connections such that the
    history array has wrapped.
    
    3.) Wrapping the array alone is not sufficient to induce the
    failure conditions. The additional condition is that, when the
    wrapping occurs, a record boundary for an individual API call
    falls on the array boundary (effectively, the cumulative
    record length of all the whole records in the array needs to
    divide cleanly by the array length such that a new record
    entry begins at the start of the wrapped array).
    
    4.) When the FDC is produced, the current index into the
    history log also needs to be at the start (in other words, the
    array has only just wrapped).
    

Problem conclusion

  • WebSphere MQ was modified to ensure that the FDC generation
    code does not continually loop round dumping the connection
    history table. Note that this fix does not address the root
    cause of why the FDC was generated in the first place.
    
    ---------------------------------------------------------------
    The fix is targeted for delivery in the following PTFs:
    
                       v7.0
    Platform           Fix Pack 7.0.1.0
    --------           --------------------
    Windows            U200306
    AIX                U823774
    HP-UX (PA-RISC)    U823665
    HP-UX (Itanium)    U823667
    Solaris (SPARC)    U823772
    Solaris (x86-64)   U824344
    iSeries            tbc_p700_0_1_0
    Linux (x86)        U823664
    Linux (x86-64)     U823773
    Linux (zSeries)    U823668
    Linux (Power)      U823666
    
    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

    IC61638

  • Reported component name

    WMQ WINDOWS V7

  • Reported component ID

    5724H7220

  • Reported release

    700

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2009-06-22

  • Closed date

    2009-06-30

  • Last modified date

    2009-06-30

  • 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 WINDOWS V7

  • Fixed component ID

    5724H7220

Applicable component levels

  • R700 PSY

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Document Information

Modified date:
30 June 2009