DB2 FOR LUW / DB2FORLUW / B10 - DB2

DB2 may return wrong results when all the following conditions 
are met: 
-The database has oracle compatibility 
(DB2_COMPATIBILITY_VECTOR=ORA) mode enabled. 
-The SELECT query being issued contains a relational operator 
predicate with SUBSTR. 
-The string argument to SUBSTR is from a table that has an index 
on that column. 
-The other operand of the relational operator is a literal. 
 
This forces the optimizer to perform an index scan using only 
the 
start/stop predicates. The index scan LOLEPOP does not contain 
the SUBSTR predicate, only the start/stop preds. 
 
Example: 
 
create table t (v VARCHAR(128)); 
create index i on t(v); 
insert into t values 'PT1', 'PT10'; 
 
select v from t where substr(v, 1, 20) = cast('PT1' as 
VARCHAR(20)); 
 
The above query returns two rows ('PT1', 'PT10') when we should 
only 
be returning one ('PT1'). 
 
The expected result (one row) is returned by the following: 
 
select v from t where v = cast('PT1' as VARCHAR(20));

**************************************************************** 
* USERS AFFECTED:                                              * 
* ALL                                                          * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to Db2 11.1 Mod 2 Fix Pack 2 iFix002 or higher       * 
****************************************************************

Workaround: 
 
Replace the literal with a table column or variable. 
Continuing with the example above: 
 
create variable myvar char(3) default 'PT1'; 
select * from test where substr(v, 1, 20) = myvar;

Db2 Version 11.1 Mod2 Fix Pack2 iFix002 for Linux, UNIX, and Windows
 Db2 Version 11.1 Mod 3 Fix Pack 3 for Linux, UNIX, and Windows
 Db2 Version 11.1 Mod3 Fix Pack3 iFix001 for Linux, UNIX, and Windows
 Db2 Version 11.1 Mod3 Fix Pack3 iFix002 for Linux, UNIX, and Windows
 

First fixed in Db2 11.1 Mod 2 Fix Pack 2 iFix002

not known / see Local fix

Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :

09.08.2017
22.12.2017
22.12.2017