DB2 FOR LUW / DB2FORLUW / 950 - 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 users who might be using the DB2_ANTIJOIN variable       * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* To improve performance DB2 converts eligible outer join to   * 
* antijoin.                                                    * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Please upgrade to DB2 version 950 fix pack 6                 * 
****************************************************************

DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows
 DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows
 

This enhancement was put into DB2 version 950 fix pack 6

keiner bekannt / siehe Local-Fix

This is an enhancement which will convert an outer join with a 
IS NULL predicate on the null producing side into an antijoin

Vorgänger  : APAR is sysrouted TO one or more of the following: IC68450 IC68451 
Nachfolger : 

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

10.03.2010
27.06.2011
05.07.2011

9.5.0