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PM75573: GLOBAL ONLINE CHANGE COMMIT FAILS LEAVING SYSTEMS HUNG IF ONE ORMORE SYSTEMS ARE DOWN AND PREPARE SPECIFIED WITH OPTION(FRCNRML)

A fix is available

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APAR status

  • Closed as program error.

Error description

  • In a 10 way IMS Datsharing Environment 4 systems were down for
    hardware upgrades when a Global Online Change was initiated with
    OPTION(FRCNRML). GOLC failed to complete on 1 of the 6 active
    systems. A QUERY MEMBER command shows a status of OLCCMT1C for
    this system indicating online change phase 1 completed. The
    other systems have completed phase 2 (OLCCMT2C), but are waiting
    for GOLC to complete on all systems. The OLCSTAT dataset has
    been corrupted with one duplicate entry and several missing
    entries.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: IMS V12 users of global online               *
    *                 change that use OPTION(FRCNRML) or           *
    *                 OPTION(FRCABND)                              *
    ****************************************************************
    * PROBLEM DESCRIPTION: An INIT OLC PHASE(COMMIT) command       *
    *                      corrupts the OLCSTAT dataset, if        *
    *                      issued when IMSs are down, after        *
    *                      INIT OLC PHASE(PREPARE) was specified   *
    *                      with OPTION(FRCNRML).                   *
    ****************************************************************
    * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
    ****************************************************************
    An INIT OLC PHASE(PREPARE) TYPE(ACBLIB) OPTION(FRCNRML)
    command is issued and executes successfully, in the case where
    4 IMSs were down because they were shut down with a
    a /CHE FREEZE command, and 6 IMSs were active.
    An INIT OLC PHASE(COMMIT) command is issued and commit phase 1
    is performed successfully by all the active IMSs.  The command
    master IMS then updates the OLCSTAT dataset incorrectly,
    corrupting it.  The command master IMSID overlays the first
    IMSID in the OLCSTAT dataset, the last IMSID is incorrectly
    deleted, and the result is that the command master IMSID
    appears in the OLCSTAT dataset twice.
    This problem occurs if the number of IMSs in the OLCSTAT
    dataset is 4 or more and at least one of the IMSs is down.
    Each OLCSTAT dataset IMS entry is 80 bytes, so 80 x 4 =
    320 bytes, which exceeds the maximum length allowed on
    a MVC instruction, so not all of the data is moved.
    This is why the commit command master appears in the
    new OLCSTAT dataset twice.
    
    Bypass:
    The IMSs that successfully completed commit phase 2
    (QUERY MEMBER TYPE(IMS) SHOW(STATUS) displays status
    of OLCCMT2C), but whose IMSIDs disappeared from the
    OLCSTAT dataset (QUERY OLC LIBRARY(OLCSTAT) SHOW(ALL)
    doesn't display them in the MbrList field)
    can be added back to the OLCSTAT dataset with the
    Global Online Change Utility (DFSUOLC0) FUNC=ADD.
    The INIT OLC PHASE(COMMIT) command should be then
    issued again, to complete the Global Online Change
    for the IMSs that committed it, to get those IMSs out
    of an online change state, so that they can start doing
    work again, can participate in the next Global Online
    Change, and don't have to coldstart.
    
    The IMS commit command master whose IMSID is duplicated
    in the OLCSTAT dataset can have one of the IMSIDs removed
    with the DFSUOLC0 utility FUNC=DEL.  The
    INIT OLC PHASE(COMMIT) command can be attempted again to
    complete the Global Online Change on this IMS and any others
    that failed to complete the Global Online Change.
    

Problem conclusion

  • GEN:
    KEYWORDS:
    
    *** END IMS KEYWORDS ***
    DFSOLC00 is corrected to use the MVCL instruction when
    moving the new OLCSTAT dataset contents to the old OLCSTAT
    dataset buffer, in case the length of the new OLCSTAT
    dataset contents exceeds 255 bytes, because of the count
    of IMSs in the old OLCSTAT dataset is 4 or more.
    

Temporary fix

  • *********
    * HIPER *
    *********
    

Comments

APAR Information

  • APAR number

    PM75573

  • Reported component name

    IMS V12

  • Reported component ID

    5635A0300

  • Reported release

    200

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt / Xsystem

  • Submitted date

    2012-10-22

  • Closed date

    2012-12-03

  • Last modified date

    2013-01-02

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

    PM75406

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

    UK83959

Modules/Macros

  •    DFSOLC00
    

Fix information

  • Fixed component name

    IMS V12

  • Fixed component ID

    5635A0300

Applicable component levels

  • R200 PSY UK83959

       UP12/12/06 P F212 Ž

Fix is available

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Document Information

Modified date:
14 December 2020