IT31996: QUERY WITH OUTER JOIN TOGETHER WITH "DBPARTITIONNUM() =" LOCAL PREDICATE NO LONGER GETS THE DESIRED PLAN.

Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• query with outer join together with "dbpartitionnum() =" local
  predicate no longer gets the desired plan with the base access
  running on just one database partition. It can cause the worse
  performance comparing with the previous release.
  
  Once the customer has installed the ptf with the fix, they must
  also set the following registry variable to revert to the
  previous behavior:
  db2set DB2_EXTENDED_OPTIMIZATION="SEP_DBPTNUM ON"
  (This registry variable can be set dynamically).
  
  Note that this setting can be combined with existing settings.
  For example, if the current setting is
  DB2_EXTENDED_OPTIMIZATION=ON
  you can add the additional setting to the end, separated by a
  comma (no spaces) as follows:
  db2set DB2_EXTENDED_OPTIMIZATION="ON,SEP_DBPTNUM ON"
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Db2 EEE configurations                                       *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Db2 Version 11.1 Fix Pack m4fp6.                  *
  * Then set registry variable as described in the error         *
  * description.                                                 *
  ****************************************************************
  

Problem conclusion

• Fixed in Db2 Version 11.1 Fix Pack m4fp6
  

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:

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSN

     UP