DB2 FOR LUW / DB2FORLUW / 970 - DB2

To improve performance, when the registry variable DB2_ANTIJOIN 
is set to anything other than NO, DB2 should convert an eligible 
 
OUTER JOIN into an ANTIJOIN. 
To be eligible, all the following must be true: 
 
1. The OUTER JOIN must have an IS NULL predicate on a column 
from the NULL producing side. 
If the column is not the join column then it must be marked NOT 
NULL. 
2. Null producing side of the OUTER JOIN must be a base table 
with no local predicates except for the IS NULL predicate. 
3. It is not a federated query. 
4. The select clause of the query must not reference any column 
from the null producing side of the left outer join. 
 
example: 
select t1.* from t1 left outer join t2 on t1.c1 = t2.c1 where 
t2.c2 IS NULL.

**************************************************************** 
* USERS AFFECTED:                                              * 
* All                                                          * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* In DB2, certain left outer join query constructs can be      * 
* safely converted into antijoin. This improves cardinality    * 
* estimation and performance.                                  * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Please upgrade to DB2 v9.7 fix pack 3a                       * 
****************************************************************

DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
 

The fix is available in DB2 v9.7 fix pack 3a

keiner bekannt / siehe Local-Fix

Datum - Problem gemeldet    :
Datum - Problem geschlossen :
Datum - der letzten Änderung:

06.05.2010
14.02.2011
14.02.2011

9.7.FP3