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PM08719: ABEND0C4 RC38 IN DSNLZVDA AT INTERMED DB2 Z/OS SERVER FOR HOP PRIVATE PROTOCOL REQUEST AFTER DB2 GENS DRDA REPLY TO REQUESTER

A fix is available

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APAR status

  • Closed as program error.

Error description

  • The abend occurrs in DSNLZVDA at intermediate DB2 z/OS Server
    for a HOP private protocol SELECT INTO when DB2 DDF generated
    the DRDA reply back to the requester site.
    The ZFDD pointer was invalid and appears to be
    overlaid. This results in the 0C4-38 abend but also can
    surface as other symptoms of overlays. db2ovrlay/K
    
    The problem can appear when using mixed protocols when hopping
    -- mixed protocols would be the use of DRDA and private
    protocol for the SQL process, and the data returned by
    the SELECT INTO is > 2000 bytes.
                                                              .
    
    Additional symptoms and keywords:
    ************************************
    574XYR00 DB2DDF DDF OVERLAY SMCOVERLAY
    ABEND0C4-38
    DSNLZLLM.DSNLZVDA+2E0
    04E-00E20006 DSNLZCAB.DSNSVSVB+08F2
    04E-00E20005 DSNLZCAB.DSNSVSVB+08F2
    04E-00E20006 DSNLZCAB.DSNSVSVB+08A8
    DB2OVRLAY/K
    

Local fix

  • local fix/workaround:
    As a local workaround, use DRDA protocol for entire SQL
    processing and hopping, remove mixed protocol
    

Problem summary

  • ****************************************************************
    * USERS AFFECTED: ALL DB2 9 for z/OS users of distributed HOP  *
    *                 site scenario using both DRDA with DB2       *
    *                 private protocol for SQL SELECT INTO         *
    ****************************************************************
    * PROBLEM DESCRIPTION: When running a HOP scenario involving   *
    *                      both DRDA with DB2 private protocol for *
    *                      SELECT INTO that returns > 2000 bytes,  *
    *                      the following abends can occur at       *
    *                      the intermediate DB2 z/OS server that   *
    *                      issued the outbound private protocol    *
    *                      SELECT INTO to another DB2 z/OS server: *
    *                                                              *
    *                      AB0C4 RC38 DSNLZLLM.DSNLZVDA +2E0       *
    *                      AB04E 00E20005 DSNLZCAB.DSNSVSVB +08F2  *
    *                      AB04E 00E20006 DSNLZCAB.DSNSVSVB +08F2  *
    *                      AB04E 00E20006 DSNLZCAB.DSNSVSVB +08A8  *
    *                                                            . *
    *                      Other abends may be possible.           *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Customer was running the following HOP scenario involving
    private protocol SELECT INTO that returned > 2000 bytes:
                                                                   .
     1. Site1 CONNECTs to DB2 z/OS Site2 using DRDA protocol
     2. While connected to Site2, Site1 requester issues an outbound
        DB2 private protocol SELECT INTO request to DB2 z/OS Site3.
        This makes Site2 an intermediate DB2 server site.
        Private protocol means SQL uses 3-part object name,
        (Site3.qualifier.table-name or an ALIAS for 3-part name) and
        is bound DBPROTOCOL(PRIVATE).
     3. The private protocol SELECT INTO causes an implicit DB2 z/OS
        connection from intermediate Site2 to Site3, and DB2 Site3
        (where the private protocol SELECT INTO actually runs)
        returns data from the SELECT to intermediate Site2 and
        the data returned exceeds 2000 bytes ( 2K ).
     4. Intermediate DB2 Site2 returns data to Site1 from
        the SELECT INTO that was initiated by Site1 requester.
                                                                   .
    The following abends occurred at the DB2 intermediate Site2
    following or during step 4 (from above) when  Site2 attempted to
    return data to Site1 from the private protocol SELECT INTO :
      ABEND0C4 RC00000038 DSNLZLLM . DSNLZVDA + 2E0
      ABEND04E RC00E20005 DSNLZCAB . DSNSVSVB + 08F2
      ABEND04E RC00E20006 DSNLZCAB . DSNSVSVB + 08F2
      ABEND04E RC00E20006 DSNLZCAB . DSNSVSVB + 08A8
    Other abends may be possible.  The abends occurred due to
    an overlay of DB2 storage as a result of intermediate DB2 Site2
    using incorrect max output length for returning data > 2K bytes
    from the SELECT INTO to requester Site1 (DB2 DDF DDIS component
    at Site2 builds a DRDA reply back to requester Site1).
    These abends can also appear to occur a short time after
    the application ends due to residual effects of the original
    storage overlay. Note that the abends do *NOT* occur if
    the SELECT INTO returns data less than or equal to 2000 bytes.
                                                                 .
    If a DB2 Data Sharing configuration at intermediate Site2 is
    used, the abends can also occur for other DB2 members of
    the same Data Sharing (DS) group at Site2 due to overlay of
    internal DB2 DDF storage shared by that DS group.
                                                                   .
    Note that this problem with data > 2K bytes does not occur for
    a cursor SELECT that uses private procotol, nor does it occur
    when only DRDA protocol is used (i.e., package is bound as
    DBPROTOCOL(DRDA) at both requester and server DB2 sites).
    These alternatives can be used to circumvent the problem, or
    if possible reduce the size of data returned to not > 2K.
                                                                   .
    

Problem conclusion

  • DB2 code as intermediate site2 was changed to provide DB2 DDF
    DDIS component at site2 correct max length of the data to be
    returned to site1 for the private protocol SELECT INTO request.
    Note that the reported abends occurred at intermediate Site2,
    and this PTF should be applied at that intermediate DB2 Site2.
                                                                   .
    Additional search keywords: DB2DDF DDF OVERLAY SMCOVERLAY
                                DBPROTOCOL
    

Temporary fix

  • AM08719
    

Comments

APAR Information

  • APAR number

    PM08719

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    YesHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-03-01

  • Closed date

    2010-07-15

  • Last modified date

    2011-02-19

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

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

    UK58821

Modules/Macros

  • DSNXEDC
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • R910 PSY UK58821

       UP10/07/30 P F007

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:
19 February 2011