IBM Support

IC68070: REDISTRIBUTE ON MDC TABLES WITH MANY CELLS CRASHES OR PERFORMS SLOWLY

Subscribe

You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • During regular processing, the redistribute utility will create
    a number of control files (CF) to record progress about the
    current redistribute operation. These files allow redistribute
    to restart after a failure, and allow the user to CONTINUE or
    ABORT the operation.
    
    Redistribute on an MDC table can create too many of these
    control files and hit one of these problems:
    1)Operating System being unable to handle the number of open
    files or
    2) Insufficient space in the file system.
    3) Slow redistribute performance due to REDISTRIBUTE keeping
    track of all the file handles on receiver partitions. This
    problem affects systems with MDC tables with many cells and a
    large number of sender partitions.
    
    During the redistribute of an MDC table, redistribute can
    generate a large number of 28 and 56 byte files in the
    redistribute control file directory. This scenario occurs when
    the redistribute utility is redistributing an MDC table, but no
    data from an MDC cell is leaving from a sender partition to a
    receiver partition.  Each MDC cell in which there is no data
    being sent, will first result in an open CF of 28 bytes, many of
    these can be opened simultaneously, because there is no
    throttling mechanism.  If too many are open, it can result in
    Operating System being unable to handle the number of files
    created.  After redistribute processing on the receiver
    partitions, the CF will eventually be closed, and the CF of 56
    bytes will stay until the end of the redistribute operation.
    Redistribute will fail to prune these unnecessary 56 byte CF
    files during processing.  This can result in too much space
    being used in the redistribute control file directory where
    these files are stored.   Due to REDISTRIBUTE having to keep
    track of these files we might hit one of the problems mentioned
    above.
    
    This problems affects a regular REDISTRIBUTE operation as well
    as a REDISTRIBUTE ABORT/CONTINUE.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * This problems affects users running regular REDISTRIBUTE     *
    * operation as well as a REDISTRIBUTE ABORT/CONTINUE.          *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * Redistribute on an MDC table can create too many control     *
    * files and hit this APAR.                                     *
    ****************************************************************
    * RECOMMENDATION:                                              *
    * Customer could abort the redistribute if it is slow and      *
    * continue after the instance recycle.                         *
    * Recommend to apply fixpack 3 to resolve the issue.           *
    ****************************************************************
    

Problem conclusion

  • This APAR is first fixed in Fixpack 3
    

Temporary fix

Comments

APAR Information

  • APAR number

    IC68070

  • Reported component name

    DB2 FOR LUW

  • Reported component ID

    DB2FORLUW

  • Reported release

    970

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-04-20

  • Closed date

    2010-09-27

  • Last modified date

    2010-09-27

  • APAR is sysrouted FROM one or more of the following:

    IC67839

  • APAR is sysrouted TO one or more of the following:

Fix information

  • Fixed component name

    DB2 FOR LUW

  • Fixed component ID

    DB2FORLUW

Applicable component levels

  • R970 PSN

       UP



Document information

More support for: DB2 for Linux, UNIX and Windows

Software version: 9.7

Reference #: IC68070

Modified date: 27 September 2010