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Problem IT21936
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Status: Closed |
DB2 OPTIMIZER MIGHT PRODUCE SUB-OPTIMAL ACCESS PLAN FOR QUERY REFERENCING COLUMN ORGANIZED TABLE WITH PRIMARY KEY |
| product: |
DB2 FOR LUW / DB2FORLUW / B10 - DB2 |
| Problem description: |
If your query joins multiple column organized tables, and a
primary key is defined on one or more of those tables, then the
optimizer might incorrectly estimate the cost of the table
access, possibly producing a sub-optimal access plan.
If you encounter this error, you will either experience
sub-optimal performance or receive a SQL0955 error. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to Db2 11.1 Mod 3 Fix Pack 3 or higher *
**************************************************************** |
| Local Fix: |
You can apply an optimization guideline to request the optimizer
to choose the optimal join order. You might also need to
examine the statistics collected to determine if they are
sufficient; for example column group statistics or a statistical
view might be required to correct potential errors in the
cardinality estimates in the optimizer's access plan. Doing so
can help protect against the optimizer choosing a sub-optimal
access plan. |
| available fix packs: |
Db2 Version 11.1 Mod 3 Fix Pack 3 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix001 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod3 Fix Pack3 iFix002 for Linux, UNIX, and Windows
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| Solution |
First fixed in Db2 11.1 Mod 3 Fix Pack 3 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 09.08.2017
19.03.2018
19.03.2018 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
