DB2 FOR LUW / DB2FORLUW / A10 - DB2

Outer join queries where the operand producing NULL values for 
unpaired rows may experience poor performance. 
- The operand producing the NULL values is a sub-select 
referencing several tables, views or nested-subselects and 
produces a very large result set. 
- The operand driving the outer join references at least two 
tables and of those tables, one table is small and filters the 
data but is not directly referenced in a join predicate with the 
NULL producing operand. 
 
In this situation the small table providing the filtering may 
not be used to effectively filter the NULL producing operand. 
 
For example 
 
SELECT ... 
FROM (SELECT T1.C3 FROM T1 INNER JOIN T2 ON T1.C1=T2.C1) as A 
             LEFT JOIN (SELECT T3.C3 FROM T3 INNER JOIN T4 ON 
T3.C2=T4.C2) as B 
            ON A.C3=B.C3; 
 
If table T1, T3 and T4 are very large tables and T2 is a very 
small table then table T2 may not be used to provide early 
filtering of the result.

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* USERS AFFECTED:                                              * 
* ALL                                                          * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* Please upgrade to db2 V10.1 FP4 and contact db2 support if   * 
* you are impacted by this APAR                                * 
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N/A

DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
 DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
 

First fixed in V10.1 FP4 
Please contact db2 support if you are impacted by this APAR

not known / see Local fix

forerunner  : APAR is sysrouted TO one or more of the following: IC98202 
follow-up : 

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

06.12.2013
02.06.2014
02.06.2014