DB2 FOR LUW / DB2FORLUW / 950 - DB2

An OR predicate that involves table join is evaluated as 
Sargable predicate at runtime. OR predicate can already be 
converted to UNION operator by DB2 query rewrite. As result each 
OR subterm predicate can become efficient start-stop key 
predicate. Such rewrite requires certain conditions. One of them 
is the query must be SELECT with DISTINCT, and another is the OR 
hosting SELECT operator must have no join predicate between OR 
referenced tables and any other table. The latter condition is 
relaxed by this enhancement. An example is 
SELECT DISTINCT ... WHERE T1.X = T2.X AND (T1.Y = T3.Y AND 
T2.Z=1 OR T1.Y = T4.Y AND T4.Z = 1). The SELECT has join 
predicate T1.X=T2.X, in which T1 is referenced by OR predicate 
but T2 is not. This enhancement enables the conversion from OR 
to UNION.

**************************************************************** 
* USERS AFFECTED:                                              * 
* All users,                                                   * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* An OR predicate that involves table join is evaluated        * 
* asSargable predicate at runtime. OR predicate can already    * 
* beconverted to UNION operator by DB2 query rewrite. As       * 
* resulteach OR subterm predicate can become efficient         * 
* start-stopkey predicate. Such rewrite requires certain       * 
* conditions. Oneof them is the query must be SELECT with      * 
* DISTINCT, andanother is the OR hosting SELECT operator must  * 
* have no joinpredicate between OR referenced tables and any   * 
* other table.The latter condition is relaxed by this          * 
* enhancement.An example is:SELECT DISTINCT ...WHERE T1.X =    * 
* T2.X AND (T1.Y = T3.Y AND T2.Z=1 OR T1.Y = T4.YAND T4.Z =    * 
* 1).The SELECT has join predicate T1.X=T2.X, in which T1      * 
* isreferenced by OR predicate but T2 is not. This             * 
* enhancementenables the conversion from OR to UNION.          * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to Version 9.5 Fix Pack 6 or later releasecontaining * 
* the fix.                                                     * 
****************************************************************

DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows
 DB2 Version 9.5 Fix Pack 7 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
 

Problem was first fixed in Version 9.5 Fix Pack 6.

keiner bekannt / siehe Local-Fix

Vorgänger  : APAR is sysrouted TO one or more of the following: IC65082 IC68559 
Nachfolger : 

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

10.12.2009
14.06.2010
14.06.2010

9.5.FP6