DB2 FOR LUW / DB2FORLUW / A50 - DB2

In DB2 DPF environments only, a specific type of query and 
resulting access might return wrong results. 
 
The following conditions will cause this issue to occur: 
- The query must have joins with join predicates using an 
explicit expression or an implicit data type conversion.  An 
example of an explicit expression is "coalesce(col1,col2) = 
coljoin". 
- The access plan must have a UNION with a Directed TQ  (DTQ) 
above it.  This is most likely to happen in a query that does a 
full outer join. 
- The access plan must also have a Hash Join (HSJOIN) chosen 
with the expression above the UNION. 
 
You can review access plans through either the explain utility 
and the db2exfmt command or using Optim Visual Explain. 
 
The problem scenario can only happen if you have all of these in 
the plan: 
- UNION 
- HSJN above UNION with the JOIN predicate using the result of 
expression (for example: COALESCE(Q9.$C3, Q9.$C1) = 
Q10.column_name)) 
- CMPEXP used in HSJN is above the UNION 
- DTQ (Directed TQ) is above the same UNION and above CMPEXP is 
used to direct results. 
 
The following is a simplified example of this scenario.  There 
is a Compute Expression (CMPEXP) in the plan below the HSJN but 
above the UNION: 
 
                      HSJOIN 
                    /---+----\ 
                 DTQ          TBSCAN 
                  |             | 
                 PIPE    TABLE: TAB_NAME 
                  | 
                CMPEXP 
                  | 
                UNION 
     /------------+------------\ 
  HSJN                          TA

**************************************************************** 
* USERS AFFECTED:                                              * 
* Database Partitioning Feature                                * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 version 10.5.0.4.                             * 
****************************************************************

To avoid hitting this APAR, execute the following and then 
recycle the instance: 
db2set DB2_TCG_DEFAULT_OPTIONS="set multi_stream_pushdown off"

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
 

The problem is first fixed in DB2 version 10.5.0.4.

keiner bekannt / siehe Local-Fix

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

09.04.2014
09.04.2014
07.04.2015