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PM18974: LOOP IN DFHCFCFN MODULE WHEN ELEMENTWARN AND ENTRYWARN PARM OF CFDT SERVER ARE SET TO A LOWER VALUE THAN THE ACTUAL.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • A loop condition with an high CPU consumption is detected
    in DFHFCMN , the Coupling Facility Data Table CFDT server .
    Problem happens when the ELEMENTWARN and ENTRYWARN parameters
    of CFDT server are SET to a lower value than the actual.
    The loop condition is detected into module DFHCFCFN into csect
    DFHCFCFN (Notify subtask, handles warnings and ALTER requests ).
    If the ELEMENTWARN and ENTRYWARN are set back to the original
    value, the loop condition doesn't stop. To go back to the normal
    bahaviour, a CFDT server startup is required.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All                                          *
    ****************************************************************
    * PROBLEM DESCRIPTION: Coupling Facility Data Table server     *
    *                      address space loops with high CPU       *
    *                      usage.                                  *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    A CFDT server has an ENTRYWARN threshold less than its
    ENTRYWARNINC setting. When the server adjusts the threshold, it
    produces a negative value which is treated as a large positive
    (unsigned) number. This makes the server loop, trying to reduce
    the next threshold even lower.
      In addition, both the shared temporary storage server and the
    named counter server can encounter the same symptom.
      Note - the same problem exists for ELEMENTWARN and
    ELEMENTWARNINC.
    KEYWORDS: NCS
    

Problem conclusion

  • The CFDT, NC and STS server logic has been changed to limit the
    decremented value to zero.
    

Temporary fix

  • FIX AVAILABLE BY PTF ONLY
    

Comments

APAR Information

  • APAR number

    PM18974

  • Reported component name

    CICS TS Z/OS V4

  • Reported component ID

    5655S9700

  • Reported release

    600

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-07-22

  • Closed date

    2010-08-12

  • Last modified date

    2010-09-02

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

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

    UK59589

Modules/Macros

  •    DFHCFCF  DFHNCCF  DFHXQCF
    

Fix information

  • Fixed component name

    CICS TS Z/OS V4

  • Fixed component ID

    5655S9700

Applicable component levels

  • R600 PSY UK59589

       UP10/08/18 P F008

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

Modified date:
02 September 2010