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PH28280: DB2 12 ZPARM SIMPLIFICATION CONTINUED:REMOVE CACHEPAC, CACHERAC, IRLMAUT, IRLMSWT, EDPROP, CHGDC, PCLOSEN, AND MGEXTSZ.

A fix is available

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APAR status

  • Closed as new function.

Error description

  • This is the fourth APAR (following PH21370, PH24358, and
    PH26317) for E491, Db2 12 zPARM simplification
    

Local fix

  • N/A
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED:                                              *
    * All Db2 12 for z/OS users and Db2 11 for                     *
    * z/OS users who are migrating to Db2 12.                      *
    ****************************************************************
    * PROBLEM DESCRIPTION:                                         *
    * This APAR removes the following                              *
    * obsolete subsystem parameters from                           *
    * Db2 12:                                                      *
    * - DSN6SPRM.CACHEPAC                                          *
    * - DSN6SPRM.CACHERAC                                          *
    * - DSN6SPRM.IRLMAUT                                           *
    * - DSN6SPRM.IRLMSWT                                           *
    * - DSN6SPRM.CHGDC                                             *
    * - DSN6SPRM.EDPROP                                            *
    * - DSN6SYSP.PCLOSEN                                           *
    * - DSN6SYSP.MGEXTSZ                                           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    The following subsystem parameters are obsolete or rarely used:
    CACHEPAC determines the amount of storage in bytes to allocate
    for caching package authorization information for all packages
    on a Db2 member. Currently, the default setting is 5242880.
    CACHERAC determines the amount of storage in bytes to allocate
    for caching routine authorization information for all routines
    on a Db2 member. Currently, the default setting is 5242880.
    IRLMAUT specifies whether Db2 is to automatically start and
    stop the IRLM. Currently, the default setting is YES.
    IRLMSWT specifies the amount of time in seconds that Db2 is
    to wait for the IRLM to start during autostart. Currently,
    the default setting is 120.
    CHGDC specifies whether CHANGE DATA CAPTURE support is enabled.
    Currently, the default setting is NO.
    EDPROP specifies whether changes to table defined for DATA
    CAPTURE CHANGES will be allowed unless they are propagated.
    Currently, the default setting is NO.
    PCLOSEN specifies the number of consecutive Db2 checkpoints
    that a page set or partition remains read-write after it is
    updated. After the specified number of checkpoints occur, Db2
    converts the page set or partition to read-only. Currently,
    the default setting is 10.
    MGEXTSZ specifies whether secondary extent allocations for
    Db2-managed data sets are to be sized according to a sliding
    scale. Currently, the default setting is YES.
    -------------------------------------------------------------
    

Problem conclusion

Temporary fix

Comments

  • To simplify configuration and management of Db2 and
    encourage best practices, the following subsystem parameters
    are removed from Db2 12: CACHEPAC, CACHERAC, IRLMAUT,
    IRLMSWT, CHGDC, EDPROP, PCLOSEN, and MGEXTSZ.
    When the fixing PTF is activated, Db2 will always do the
    following actions:
    - set the amount of storage to allocate for caching package
    authorization information for all packages and for caching
    routine authorization information for all routines on a Db2
    member to 10485760 bytes. However, if COMCRIT=YES, the
    amount of storage is set to 0 bytes.
    - automatically start and stop the IRLM as part of Db2
    startup and shutdown.
    - set the amount of time that Db2 is to wait for the IRLM
    to start during autostart to 120 seconds.
    - always allow changes to tables defined with DATA CAPTURE
    CHANGES, but the SQL changes will not be propagated. Db2 will
    now behave as if, before this APAR, CHGDC and EDPROP are both
    set to NO (or DPROP SUPPORT field = 1 on the panel DSNTIPO).
    - set the number of consecutive Db2 checkpoints that a page
    set or partition remains read-write after it is updated to
    32767. If the data set pseudo close process that is
    triggered by PCLOSEN is more frequent than by PCLOSET,
    users should update PCLOSET value accordingly as needed.
    - automatically optimize the secondary extent allocations
    for Db2-managed data sets to be sized according to a sliding
    scale.
    -------------------------------------------------------------
    Pre-APPLY guidance for customers who currently set
    MGEXTSZ=NO:
    -------------------------------------------------------------
    If you currently set MGEXTSZ=NO on Db2 12, be aware that any
    Db2 subsystem or data sharing member where this PTF is
    activated, Db2 automatically optimizes the secondary
    extent allocations for Db2-managed data sets to be sized
    according to a sliding scale.
    Activating the PTF on a Db2 subsystem or data sharing
    member means that you have:
    - applied it there; and then
    - rebuilt the Db2 subsystem parameter (DSNZPxxx) module;
      and then
    - either restarted Db2 or run the -SET SYSPARM LOAD or
      RELOAD command with the rebuilt subsystem parameter
      (DSNZPxxx) module
    If you currently set MGEXTSZ=NO on Db2 11, including members
    in data sharing coexistence with Db2 12, be aware that Db2
    automatically optimizes the secondary extent allocations
    for Db2-managed data sets to be sized according to a sliding
    scale on any Db2 subsystem or data sharing member that you
    have migrated to Db2 12 where this PTF is activated.
    Therefore, before you either :
    - apply the fixing PTF for this APAR on a Db2 12 subsystem
      (or any member of a Db2 12 data sharing group); or
    - migrate a Db2 11 subsystem (or any member of a Db2 11 data
      sharing group) to Db2 12 with this PTF applied
    you need to rebuild its Db2 subsystem parameter (DSNZPxxx)
    module to use MGEXTSZ=YES (on all members in data sharing).
    Do not run the -SET SYSPARM or restart Db2 command on any
    member until you have switched all members to use
    MGEXTSZ=YES. After switching (all members) to MGEXTSZ=YES,
    run (on all members in data sharing) the -SET SYSPARM
    command or restart Db2 (all members in data sharing)
    to initiate the change.
    

APAR Information

  • APAR number

    PH28280

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    C10

  • Status

    CLOSED UR1

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2020-08-06

  • Closed date

    2020-10-01

  • Last modified date

    2020-11-02

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

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

    UI71872

Modules/Macros

  • DSNTINMF DSNDQWPZ DSNTIP7  DSNWZIFC DSNTIDXA DSNTIVMD DSNTIJUZ
    DSNTINST DSNTIDXC DSNTIWIA DSNTIDXB DSNTIVIA DSNTIWMD DSNTIWIE
    DSNTIVIE DSN6SYSP DSN@XAZP DSN6SPRM DSNTXAZP DSNTIWPC DSNTIPP
    DSNDSPRM DSN6SPRC DSNTIPO  DSNTIPL1 DSNTIPI  DSNTIVMN DSNTIWMN
    DSNTIVAF DSNTIVIN DSNTIWMS DSNTIVMS DSNTIWAF DSNTIWIN
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RC10 PSY UI71872

       UP20/10/09 P F010

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:
31 March 2021