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OA42070: DB2 BUFFER POOLS SHRINK BELOW INITIAL SIZE WITHOUT NEED.

A fix is available

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APAR status

  • Closed as program error.

Error description

  • In z/OS V2.1 DB2 Buffer Pools can shrink either if the system is
    storage-constraint and some storage must be freed, or if WLM
    determines that the Buffer Pool can be shrunk without impacting
    the service classes using the Buffer Pool.
    In both cases the Buffer Pool can shrink down to its defined
    minimum size. For the latter case, though, it is preferable to
    shrink only down to its initial size. For this case also, WLM
    should check in every interval if some Buffer Pool is eligible
    for shrinking.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All users of z/OS 2.1  (HBB7790)             *
    ****************************************************************
    * PROBLEM DESCRIPTION: In z/OS V2.1 DB2 Buffer Pools can       *
    *                      shrink either if the system is          *
    *                      storage constrained and some storage    *
    *                      must be freed, or if WLM determines     *
    *                      that the Buffer Pool can be shrunk      *
    *                      without impacting the service classes   *
    *                      using the Buffer Pool.                  *
    *                                                              *
    *                      In both cases the Buffer Pool can       *
    *                      shrink down to its defined minimum      *
    *                      size. For the latter case, though, it   *
    *                      is preferable to shrink only down to    *
    *                      its initial size. For this case also,   *
    *                      WLM should check in every interval if   *
    *                      some Buffer Pool is eligible for        *
    *                      shrinking.                              *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Entry IRAPABPC in module IRAPABPD uses min_size to check if a
    buffer pool has reached the lower limit for size reduction.
    
    This entry point also checks if one minute has elapsed since the
    last time that buffer pools were evaluated to see if any can be
    reduced in size.
    
    Module IRAMXPLV is not at the correct development level
    

Problem conclusion

  • Entry IRAPABPC in module IRAPABPD has been updated to use
    reg_size to check if a buffer pool has reached the lower limit
    for size reduction.
    
    The check that one minute has elapsed is removed, so every
    interval buffer pools are evaluated if one of them can be
    reduced in size.
    
    Module IRAMXPLV is regenerated from the CASE libraries.
    

Temporary fix

Comments

APAR Information

  • APAR number

    OA42070

  • Reported component name

    SRM - SYS RSRCE

  • Reported component ID

    5752SC1CX

  • Reported release

    790

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2013-04-24

  • Closed date

    2013-06-11

  • Last modified date

    2017-02-07

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

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

    UA69482

Modules/Macros

  • IRAMXPLV IRAPABPD
    

Fix information

  • Fixed component name

    SRM - SYS RSRCE

  • Fixed component ID

    5752SC1CX

Applicable component levels

  • R790 PSY UA69482

       UP13/06/26 P F306

Fix is available

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Document Information

Modified date:
07 February 2017