PH67241: HANG IN NATIVE MODE UNLOADING SAME TABLE TO A SINGLE OUTPUT DS IF VUU036/GBLPARAL AND VUU044/SUBTKSOF SET TO YES

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• An unload hangs and stops consuming CPU.
  
  This occurs when ALL the following conditions are fulfilled:
  - an UNLOAD statement specifies several logical unloads (SELECT
    statement and OUTDDN option)
     - from the same table stored in a partitioned tablespace
     - and run in native mode
     - that share the same output dataset
  - partition parallelism is used for this unload
  - the parmlib parameter VUU036/GBLPARAL is set to YES
  - the parmlib parameter VUU044/SUBTKSOF is set to YES
  

Local fix

• Consider either of the following:
  
  - run the unload in SQL mode by specifying DB2 FORCE. This
    solves the issue for the unload in question but reduces the
    amount of CPU offloaded to zIIP processors for it.
  
  - set the VUU044/SUBTKSOF parmlib parameter to NO (which is the
    recommended value). This allows to keep the same zIIP usage
    but impacts any unload run in native mode from data sets per
  partition into a single output file.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: Users of Db2 High Performance Unload for     *
  *                 z/OS                                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: An unload hangs and stops consuming     *
  *                      CPU.                                    *
  *                                                              *
  *                      This occurs when all the following      *
  *                      conditions are fulfilled:               *
  *                                                              *
  *                          - an UNLOAD statement specifies     *
  *                            several logical unloads (SELECT   *
  *                            statement and OUTDDN option)      *
  *                                                              *
  *                             - from the same table stored in  *
  *                               a partitioned tablespace       *
  *                             - and run in native mode         *
  *                             - that share the same output     *
  *                               dataset                        *
  *                                                              *
  *                         - partition parallelism is used for  *
  *                           this unload                        *
  *                                                              *
  *                         - the parmlib parameter              *
  *                           VUU036/GBLPARAL is set to YES      *
  *                                                              *
  *                         - the parmlib parameter              *
  *                           VUU044/SUBTKSOF is set to YES      *
  *                                                              *
  *                      Local fix: consider either of the       *
  *                      following:                              *
  *                                                              *
  *                         - run the unload in SQL mode by      *
  *                           specifying DB2 FORCE. This solves  *
  *                           the issue for the unload in        *
  *                           question but reduces the amount    *
  *                           of CPU offloaded to zIIP           *
  *                           processors for it.                 *
  *                                                              *
  *                         - set the VUU044/SUBTKSOF parmlib    *
  *                           parameter to NO (which is the      *
  *                           recommended value). This allows    *
  *                           to keep the same zIIP usage but    *
  *                           impacts any unload run in native   *
  *                           mode from data sets per partition  *
  *                           into a single output dataset       *
  ****************************************************************
  * RECOMMENDATION: Apply the PTF                                *
  ****************************************************************
  HANG IN NATIVE MODE UNLOADING SAME TABLE TO A SINGLE OUTPUT DS
  IF VUU036/GBLPARAL AND VUU044/SUBTKSOF SET TO YES
  

Problem conclusion

• Code has been changed to fix this problem
  

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:

Modules/Macros

• INZUTILK
  

Fix information

• Fixed component name

  DB2 HI PERF UNL

• Fixed component ID

  5697F4400

Applicable component levels

• R520 PSY UO04514

     UP25/08/23 P F508

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.