DB2 FOR LUW / DB2FORLUW / 970 - DB2

When compiling a query, optimizer can generate multiple access 
plans that use different compilation of MQTs and use statistical 
view to adjust the cardinality of matched query join operators. 
Replicated MQT is commonly used in DPF and it can be enforced by 
either registry control 
"DB2_EXTENDED_OPTIMIZATION=FORCE_REPLICATED_MQT_MERGEA" or 
optimizer guideline "<MQTENFORCE TYPE='REPLICATED'/>" . A 
replicated MQT must have no aggregation. MQT having GROUP BY 
operation is called group-by MQT. When a base table has both 
replicated MQT and group-by MQT dependent on it, if replicated 
MQT is enforced and group-by MQT is not enforced, optimizer used 
to prune group-by MQT plan since it doesn't use the replicated 
MQT which is enforced. However the enforcement of replicated MQT 
should be in effect only at deciding among plans of base object 
access including base table and non-group-by MQTs and should not 
be applied to group-by MQT plan. This fix allows group-by MQT 
plan to be used if its plan costing is not more expensive than 
the base object access plan. 
 
This fix also increases of chance of using statistical view in 
optimizer planing. Query compiler attempts to substitute some 
subquery block with group-by MQT and adjust the cardinality of 
some other subquery block by using the matched statistical view. 
The group-by MQT used to reduce optimizer's use of statistical 
view. That is fixed by this APAR.

**************************************************************** 
* USERS AFFECTED:                                              * 
* ALL                                                          * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See Error Description                                        * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to DB2 V9.7 Fix Pack 7                               * 
****************************************************************

N/A

DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
 DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
 

First fixed in DB2 V9.7 Fix Pack 7

not known / see Local fix

forerunner  : APAR is sysrouted TO one or more of the following: IC89174 
follow-up : 

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

22.05.2012
17.12.2012
17.12.2012

9.7.FP7