DB2 FOR LUW / DB2FORLUW / A50 - DB2

A select distinct subquery may be consolidated to the outer 
query block by db2 compiler in sought of better join planning 
for the outer query block, although that postpones the 
duplicated rows removal of the subquery. But if the select 
distinct subquery result participates in no join predicate of 
the outer query block, i.e. this outer query has cartesian join, 
preserving select distinct to remove duplication before 
performing the cartesian join is a better plan. This heuristic 
used to be available to subquery "select distinct from 
base_table" and is now extended to subquery "select distinct 
from alias"

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* USERS AFFECTED:                                              * 
* ALL                                                          * 
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* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
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* RECOMMENDATION:                                              * 
* Upgrade to V10.5 Fixpack 3                                   * 
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Manually rewrite "select distinct col1, col2, ..., colN from 
alias" to "select col1, col2, ..., colN from alias group by 
col1, col2, ..., colN".

DB2 Cancun Release 10.5.0.4 (also known as Fix Pack 4) for Linux, UNIX, and Windows
 DB2 Version 10.5 Fix Pack 9 for Linux, UNIX, and Windows
 

Upgrade to V10.5 Fixpack 3

not known / see Local fix

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

07.02.2014
17.09.2014
17.09.2014