PM51974: IRLM LOCKING NOT WORKING CORRECTLY

A fix is available

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • Running a DDLT0 BMP and using a PROCOPT=A PSB, do a GHU and DLET
    to the LAST root segment in a PHIDAM partition. Then put the job
    into a hold by placing a DFSDDLT0 WTOR control card immediately
    after the DLET. Run a second DDLT0 BMP on the same system using
    the same PSB and issue a qualified GHU against the same root
    segment which has just been deleted (but not yet committed) by
    the first BMP. The second job completes with RC=0 returning a
    'GE' status for the GHU call. This is wrong since the job should
    have been held on an IRLM lock until the first DLET job
    has completed.
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All IMS V11 HALDB PHIDAM users.              *
    ****************************************************************
    * PROBLEM DESCRIPTION: Potential data integrity issue when     *
    *                      the last root segment in a HALDB        *
    *                      partition is deleted.                   *
    ****************************************************************
    * RECOMMENDATION: INSTALL CORRECTIVE SERVICE FOR APAR/PTF      *
    ****************************************************************
    When multiple dependent regions are accessing the same HALDB
    PHIDAM database, if dependent region 1 deletes the last root
    segment in the partition, but does not immediately commit the
    update, if a second dependent region issues a GET call to
    retrieve the root that was just deleted, the second dependent
    region will receive a GE status ( STATUSGE ) even though
    dependent region 1 has not committed the delete.  If dependent
    region 1 then fails and has to do backout, the STATUSGE
    returned to dependent region 2 is invalid.
    Because the root segment deleted by dependent region 1 was the
    last root in the partition, dependent region 2 does not ENQ on
    the next higher key, which would be the X'FF's key, allowing
    dependent region 2 to not wait until the commit of dependent
    region 1, returning the STATUSGE immediately and potentially
    causing a data integrity issue.
    

Problem conclusion

  • GEN:
    POSTREQ PM81754
    KEYWORDS:
    
    *** END IMS KEYWORDS ***
    The following module and macro have been modified to correct
    the reported problem:
    
    **********
    * DFSJCB *
    **********
    New flag JCBLKAFF has been added in flag byte JCBR3 to indicate
    that a lock on the X'FF's key is needed to assure data
    integrity.
    
    ************
    * DFSDLR00 *
    ************
    Code has been added in the BYKEY routine, after label KEYEND50,
    when a segment NOTFOUND condition is detected to determine if a
    lock on the X'FF's key is required.  If the lock is needed,
    flag JCBLKAFF is set and a branch to label BYKEY2 is done to
    ENQ on the X'FF's key to protect the integrity of the database.
    

Temporary fix

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

Comments

  • REPINNED RP13/01/30 (ATXT) TO ADD POSTREQ PM81754 INFO.
     **** PE13/01/30 PTF IN ERROR. SEE APAR PM81754 FOR DESCRIPTION
    ž**** PE13/01/30 FIX IN ERROR. SEE APAR PM81754  FOR DESCRIPTION
    

APAR Information

  • APAR number

    PM51974

  • Reported component name

    IMS V11

  • Reported component ID

    5635A0200

  • Reported release

    101

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-11-10

  • Closed date

    2012-10-20

  • Last modified date

    2013-03-29

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

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

    PM53588 UK82801 UK82802

Modules/Macros

  •    DFSDLR00 DFSJCB
    

Fix information

  • Fixed component name

    IMS V11

  • Fixed component ID

    5635A0200

Applicable component levels

  • R100 PSY UK82801

       UP12/10/23 P F210

  • R101 PSY UK82802

       UP12/10/23 P F210

Fix is available

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Document information


More support for:

IMS

Software version:

101

Reference #:

PM51974

Modified date:

2013-03-29

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