PM06953: SINGLE ENCLAVE SUPPORT FOR CP QUERY PARALLELISM

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You can track all active APARs for this component.

APAR status

  • Closed as program error.

Error description

  • SINGLE ENCLAVE SUPPORT FOR CP QUERY PARALLELISM
    DB2PARALL/K
    

Local fix

Problem summary

  • ****************************************************************
    * USERS AFFECTED: All DB2 9 users of CP query parallelism.     *
    ****************************************************************
    * PROBLEM DESCRIPTION: When a parallel query is offloaded to   *
    *                      the zIIP engines, each parallel task    *
    *                      is scheduled in its own enclave and     *
    *                      managed by Work Load Manager as such.   *
    *                                                              *
    *                      As a result, there is no way for a      *
    *                      user to consistently define periods     *
    *                      to distinguish between, for example,    *
    *                      individual enclaves of a                *
    *                      high-consumption query from a           *
    *                      single enclave of a low-consumption     *
    *                      query.  This limits a user's ability    *
    *                      to utilize WLM to favor                 *
    *                      low-consumption workloads.              *
    ****************************************************************
    * RECOMMENDATION:                                              *
    ****************************************************************
    Because z/OS did not initially provide a TIMEUSED support to
    include a time-on-CP function vs. time-on-zIIP for multiple
    SRBs in an enclave, each parallel task needed to be scheduled
    in its own enclave in order to extract the correct the
    accounting information.
    
    However, that created a problem where WLM could not make the
    distinction between one of many enclaves belonging to a
    high-consumption query from a single enclave belonging to a
    low-consumption query.  As such, a user cannot define periods
    that consistently favor low-consumption queries.
    

Problem conclusion

  • DB2 code has been modified to create only one enclave for all
    parallel tasks under a query.  This allows WLM to manage each
    query as a whole, and properly distinguish between
    high-consumption queries and low-consumption queries so that
    users can define periods to consistently favor one set or
    the other.
    

Temporary fix

Comments

APAR Information

  • APAR number

    PM06953

  • 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

    2010-02-05

  • Closed date

    2010-07-16

  • Last modified date

    2011-04-27

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

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

    UK58871

Modules/Macros

  •    DSNDACE  DSNDTMQE DSNDTMT  DSNTTENE DSNTTRUN
    DSNTTTC  DSNWAACT DSNWMCRS DSNWVAPR DSNWVSR1 DSNWVZPS DSNWVZSA
    DSNXERT  DSNX9CAL DSNX9SPI DSNX9SPS DSNX9WCA
    

Fix information

  • Fixed component name

    DB2 OS/390 & Z/

  • Fixed component ID

    5740XYR00

Applicable component levels

  • R910 PSY UK58871

       UP10/07/31 P F007

Fix is available

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Document information


More support for:

DB2 for z/OS

Software version:

910

Reference #:

PM06953

Modified date:

2011-04-27

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