home clear 64x64
en blue 200x116 de orange 200x116 info letter User
suche 36x36
Latest versionsfixlist
11.1.0.7 FixList
10.5.0.9 FixList
10.1.0.6 FixList
9.8.0.5 FixList
9.7.0.11 FixList
9.5.0.10 FixList
9.1.0.12 FixList
Have problems? - contact us.
Register for free anmeldung-x26
Contact form kontakt-x26

DB2 - Problem description

Problem IC68031 Status: Closed

THE OPTIMIZER MAY FAVOR A FULLY QUALIFIED UNIQUE INDEX WITH FEWER
COLUMNS OVER A UNIQUE NOT FULLY QUALIFIED UNIQUE INDEX

product:
DB2 FOR LUW / DB2FORLUW / 980 - DB2
Problem description:
The optimizer may favor a unique index that is fully qualified 
over another unique index that is not fully qualified having 
more columns.  This may be true, even if the second index offers 
index only access. 
 
(Fully qualified means that all the columns of the index have 
equality predicates and when specified through a join, all the 
join predicates have to be between the same tables.)
Problem Summary:
**************************************************************** 
* USERS AFFECTED:                                              * 
* All.                                                         * 
**************************************************************** 
* PROBLEM DESCRIPTION:                                         * 
* See above.                                                   * 
**************************************************************** 
* RECOMMENDATION:                                              * 
* Upgrade to version 9.8 Fix Pack 3 or a later release that    * 
* includes the fix.                                            * 
****************************************************************
Local Fix:
Build unique indexes that are a superset of smaller unique 
indexes using include columns: 
 
For Example, if the original definition was: 
 
   unique index1 (a) 
   unique index2 (a,b,c) 
 
 
 
In the above example, index2 is really unique on column a, so 
columns b and c are not needed to be part of the unique 
definition.  The second index could be defined as: 
 
   unique index2 (a) include (b,c)
available fix packs:
DB2 Version 9.8 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.8 Fix Pack 4 for AIX and Linux
DB2 Version 9.8 Fix Pack 5 for AIX and Linux

Solution
Problem was first fixed in Version 9.8 Fix Pack 3.
Workaround
not known / see Local fix
Timestamps
Date  - problem reported    :
Date  - problem closed      :
Date  - last modified       :
20.04.2010
22.12.2010
22.12.2010
Problem solved at the following versions (IBM BugInfos)
9.8.FP3
Problem solved according to the fixlist(s) of the following version(s)
9.8.0.3 FixList