IT20692: POOR PERFORMANCE WHEN OJ AND JOIN ON IT HAS SAME TABLE

Db2 Version 11.1 Mod4 Fix Pack4 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 4 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 5 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 7 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• Description: DB2 query may show poor performance when the
  following conditions are met:
  1. The query has one or more Outer Joins
  2. There is join on top of Outer Join(s)
  2. Row Preserving side of an Outer Join has a table, also used
  in the join on top of this OuterJoin.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * ALL                                                          *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Db2 11.1 Mod 4 Fixpack 4 or higher                *
  ****************************************************************
  

Problem conclusion

• First fixed in Db2 11.1 Mod 4 Fixpack 4
  

Temporary fix

Comments

APAR Information

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

  IT20642

• 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