PM28626: CORRECTION OF DRDA USING TCP/IP EXECUTION VARIATION AND HANDLING OF ENCLAVE CONTROL STRUCTURE ANOMALIES

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

  • DB2DDF DB2TCPIP DB2DRDA
    DRDA TCP/IP ZIIP
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All Distributed Data Facility (DDF) users.   *
    *                 Specifically where remote clients access     *
    *                 DB2 via DRDA over TCP/IP.                    *
    ****************************************************************
    * PROBLEM DESCRIPTION: DRDA TCP/IP zIIP related changes.       *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    1. In cases where DRDA applications create extended duration
       work threads in DB2, for example through extensive use of
       held cursors, the zIIP utilization levels can become more
       variable after applying the PTF for APAR PM12256.
    2. For customers running on System z complexes where the
       processor speed of the zIIP processors differ from that
       of the general purpose processors, after applying the PTF
       for APAR PM12256:
       a. the execution time of DRDA threads with multiple SQL
          statements can be more variable, particularly in cases
          where DRDA applications create extended duration work
          threads in DB2, for example through the use of held
          cursors.
       b. the performance of a single DRDA SQL statement can
          experience more variation from one execution to the
          next, especially for longer running SQL statements.
    3. Enclaves with associated control structures not established
       by DB2 can result in unauthorized processor utilization.
    

Problem conclusion

  • This APAR alone addresses problems 1, 2a and 3 listed above.
    
    For problem 2b, this APAR must work in conjunction with z/OS
    APAR OA35146.
    
    For problem 3, if DB2 detects an unauthorized control
    structure, it will delete the identified enclave and execute
    the DRDA request under a pre-emptable SRB, outside of its
    normal WLM enclave service class, on a general purpose
    processor and not on a zIIP.  This could cause some changes
    in customer established dispatching priorities for this work,
    and it could cause changes in WLM service class reporting.
    A new indicator is provided in the DB2 Accounting record
    (IFCID 003) that will indicate that these actions have been
    taken with regard to the affected DRDA request.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM28626

  • Reported component name

    DB2 OS/390 & Z/

  • Reported component ID

    5740XYR00

  • Reported release

    A10

  • Status

    CLOSED PER

  • PE

    NoPE

  • HIPER

    NoHIPER

  • Special Attention

    NoSpecatt

  • Submitted date

    2010-12-09

  • Closed date

    2011-04-08

  • Last modified date

    2011-05-02

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

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

    UK66598 UK66600 UK66599

Modules/Macros

  •    DSNB1GET DSNB2DCL DSNDDPSB DSNDF002 DSNDQWAC
    DSNDSCOM DSNDWWFR DSNLAGNT DSNLAGNX DSNLARAL DSNLCAIA DSNLCRTD
    DSNLCRTR DSNLCTRC DSNLDTI2 DSNLDUMP DSNLIINI DSNLIRTR DSNLQACT
    DSNLQCTL DSNLQINA DSNLSRBR DSNLSSRB DSNLSSST DSNLTACC DSNLTRAG
    DSNLXENV DSNOLIKE DSNTTRUN DSNTTTC  DSNVSDC  DSNVSDC0 DSNVSR
    DSNVSRR  DSNVSRX  DSNWAACT DSNWDFDI DSNWDFDS DSNWDST1 DSNWMCRS
    DSNWVAPR DSNWVSR1 DSNWVZPS DSNWVZSA DSNXERT  DSNXESTS DSNXOCS
    DSNXSFML DSNXSFRT DSNXSMRL DSNXSRID DSNXXMRD DSNXXRID DSNX9CAL
    DSNX9SPI DSNX9SPS DSNX9WCA DSNYSTRT
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • RA10 PSY UK66598

       UP11/04/23 P F104

  • R810 PSY UK66599

       UP11/04/26 P F104

  • R910 PSY UK66600

       UP11/04/26 P F104

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


More support for:

DB2 for z/OS

Software version:

A10

Reference #:

PM28626

Modified date:

2011-05-02

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