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PM41119: ABEND04E RC00E2000B DSNXERT2 DSNSVBK +062A STORAGE SHORTAGE / LEAK

A fix is available

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APAR status

  • Closed as program error.

Error description

  • ABEND04E RC00E2000B DSNXERT2 DSNSVBK +062A storage shortage /
    leak . Major storage consumer is DSNXERT2 allocating SQLDA
    blocks . Abend symptoms occurred at the intermediate site in
    implicit DRDA hop scenario .
    .
    Additional symptoms:
    ABEND04E RC00E20003 DSNXERT2 DSNSVBK +05EE  +05EA
    ABEND04E RC00E20016 DSNSVSTK+0656
    MSGDSNV508I  SQLSTORAGE  DB2STGLK/K
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: DB2 9 for z/OS users of static 3-part name   *
    *                 SELECT INTO and DBPROTOCOL(DRDA)             *
    *                 (known as implicit DRDA) in a DRDA HOP       *
    *                 scenario                                     *
    ****************************************************************
    * PROBLEM DESCRIPTION: ABEND04E RC00E2000B                     *
    *                      DSNXERT2 DSNSVBK +062A                  *
    *                                                              *
    *                      or                                      *
    *                                                              *
    *                      significant CPU performance degradation *
    *                      for DSNSVBK occurred while running      *
    *                      an application that used                *
    *                      a static implicit DRDA SELECT INTO in   *
    *                      a multi-site DRDA HOP scenario          *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    
    ABEND04E RC00E20004 in DSNSVBK  occurred in a long running
    DB2 thread that ran an extended workload of applications that
    contained static SELECT INTO statements using implicit DRDA
    (SQL bound with DBPROTOCOL(DRDA) and referencing 3-part object
    names) in a multi-site HOP scenario.
    Reason code 00E20004 indicates that DB2 has exhausted its
    available memory storage ( out of storage condition ).
                                                                   .
    The SELECT INTO is also known as a singleton SELECT (as compared
    to a cursor SELECT), and static implicit DRDA SQL statements
    have value 'D' in DB2 catalog column SYSIBM.SYSPACKSTMT.STATUS .
                                                                   .
    A HOP site scenario can involve DRDA CONNECT SQL (and/or
    a remote stored procedure ), implicit DRDA SQL and multiple DB2
    sites as follows:
       Requester_site1 -> DB2_site2 -> DB2_site3 (or back to site1)
    where
      "->" means explicit or implicit DRDA connect,
      Requester_site1 can be DB2 z/OS or non-z/OS client,
      DB2_site2 is known  as the " intermediate " site, and
      DB2_site3 is known as the " downstream " server.
    
    The AB04E RC00E20004 occurred at the intermediate site
    (DB2_site2).
                                                                   .
    When we examined a storage map of the intermediate DB2's ADMF
    Agent Local ( AGL ) storage pool in the dump provided, we saw
    an excessive number of DB2 internal blocks with eyecatcher SQLDA
    that were allocated by DB2 csect DSNXERT2.  This particular
    internal SQLDA block is allocated by DB2 specifically to process
    static SELECT INTO statements at the intermediate DB2 in a HOP
    scenario. After further review, we determined that a storage
    leak for this SQLDA block occurred.
    
    This excessive number of SQLDA blocks can also cause
    a noticeable CPU performance degradation focused in DB2 csect
    DSNSVBK due to the increasingly growing chain of SQLDA blocks
    that DSNSVBK had to follow each time an allocation of a new
    SQLDA block was needed for a static SELECT INTO case.
    

Problem conclusion

  • DB2 code has been corrrected to free this internal SQLDA block
    after its use at the intermediate DB2 when processing static
    implicit DRDA SELECT INTO statements.
                                                                   .
    This also improves CPU performance for DB2 csect DSNSVBK.
                                                                   .
    The PTF for this apar must be applied at the intermediate DB2
    (DB2_site2) of a HOP site scenario where the 'out of storage'
    AB04E in DSNSVBK occurred or where the CPU performance
    degradation for DSNSVBK is observed.
                                                                   .
    Additional search keywords: SQLPERFORMANCE PERF DBPROTOCOL DDF
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM41119

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    910

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2011-06-08

  • Closed date

    2011-07-12

  • Last modified date

    2011-08-01

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

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

    UK69691

Modules/Macros

  • DSNXERT2
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • R910 PSY UK69691

       UP11/07/29 P F107

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:
01 August 2011