DB2 FOR LUW / DB2FORLUW / A50 - DB2

DB2 may produce wrong result if the following conditions are 
met: 
1) The query has OR predicate 
2) At least one of the branches of OR has AND predicate 
3) The AND predicate has NULL IS NULL as one branch predicate 
e.g. 
select * from t where (NULL IS NULL and c1='Y' ) or (c1='N' ) 
 
This issue only exists on V10.5fp7 .

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* USERS AFFECTED:                                              * 
* This issue only exists on V10.5fp7                           * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* Upgrade to V10.5fp8                                          * 
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1.Remove "NULL IS NULL" predicate from the query. 
2. Change the value of DFT_QUERYOPT to 3 (NOTE: We may have 
performance issue with this setting ) 
db2 update db cfg using DFT_QUERYOPT 3 immediate 
3. Set the QUERYOPT value specific to the query using Optimizer 
Guidelines: 
db2set DB2_OPTPROFILE=YES 
db2 terminate 
db2stop 
db2start 
db2 connect to testdb 
 
db2 "select * from tmp where (NULL IS NULL and IAN_STATUS='Y' ) 
or (1 IS NULL and IAN_MOVE_STATUS='' ) 
/* <OPTGUIDELINES> 
<QRYOPT VALUE='3'/> 
</OPTGUIDELINES> */"

not known / see Local fix

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

19.05.2016
26.09.2016
07.11.2016