PM06953: SINGLE ENCLAVE SUPPORT FOR CP QUERY PARALLELISM

Obtain the fix for this APAR.

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 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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