PM60852: DFSISTS0 MAY APPEAR TO BE LOOP WHEN PROCESSING LONG CHAINS OF MESSAGE SWITCHED TRANSACTIONS.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • DFSISTS0 processing will become very slow when processing long
    chains of message switched transactions and may appear to be
    looping.  In the supplied SLDS file, some Type x'03' records
    show very high message switch counts, such as...
    .
    Field     Value     Description
    --------  ------    ------------------------------------------
    MSGPREFI  65,535    NO. OF PGM-PGM MSG SWITCHES TO GET TO THIS
                        INPUT
             .
             TRAN                : WQSESB
             LOG Sequence Number : 00000000020BAD8F
           -
           Many records show values over 60,000.
    -
    With a sufficient number of these long chains, it may not be
    possible to run DFSISTS0 with some SLDS files.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All IMS V11 users.                           *
    ****************************************************************
    * PROBLEM DESCRIPTION: DFSISTS0 takes a very long time to      *
    *                      complete when processing a log with     *
    *                      a high number of program switches       *
    *                                                              *
    ****************************************************************
    * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
    ****************************************************************
    DFSISTS0 builds a tree to represent message and transaction
    events recorded by the input log file.  Program switches are
    included in the tree as nodes, so logs with high numbers of
    program switches result in very large trees.  The number of
    nodes between the root of the tree and a leaf node can become
    extremely large.  DFSISTS0 was leaving the tree intact
    throughout the time required to process the entire input log,
    so the tree keeps growing as DFSISTS0 works through the log
    data.  Because the tree was being traversed constantly as it
    grew, the time required to reach destination nodes was
    increasing dramatically.  At times, it could appear that
    DFSISTS0 was looping because so much calculation was required
    to find nodes in the tree.
    

Problem conclusion

  • GEN:
    KEYWORDS:
    
    *** END IMS KEYWORDS ***
    DFSISTS0 now maintains the internal tree differently.
    Stastics are generated from tree nodes as the log is being
    consumed.  Once the required information has been pulled from
    the input log and statistics can be generated for a particular
    node, the tree can be pruned by removing nodes that are no
    longer needed.  DFSISTS0 continues collecting statistics and
    pruning nodes until all input data has been read.  This prevents
    the tree from becoming so large that it significantly hurts
    performance.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM60852

  • Reported component name

    IMS V11

  • Reported component ID

    5635A0200

  • Reported release

    100

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2012-03-20

  • Closed date

    2013-10-03

  • Last modified date

    2013-11-04

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

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

    PM93934 PM93935 UK98210

Modules/Macros

  •    DFSISTS0
    

Fix information

  • Fixed component name

    IMS V11

  • Fixed component ID

    5635A0200

Applicable component levels

  • R100 PSY UK98210

       UP13/10/08 P F310

Fix is available

  • Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.



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Document information


More support for:

IMS

Software version:

100

Reference #:

PM60852

Modified date:

2013-11-04

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