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Problem IC91751
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Status: Closed |
OPTIMIZER MIGHT CHOOSE NON-OPTIMAL JOIN IN PRESENCE OF CYCLES WHEN DB2_REDUCED_OPTIMIZATION=JOIN IS SET |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
When the DB2_REDUCED_OPTIMIZATION registry variable setting
includes the JOIN value, the optimizer might choose a
non-optimal join order or join alternative, such as a hash join
over a nested loop join, for star join eligible queries that
include join cycles. This is more likely to occur in Version
10.1 Fix Pack 2. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Environments with DB2_REDUCED_OPTIMIZATION registry variable *
* setting that includes the JOIN value is affected. *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 10.1 Fix Pack 3. *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
|
| Solution |
Problem fixed in DB2 Version 10.1 Fix Pack 3. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 22.04.2013
17.10.2013
17.10.2013 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.3
|
 |
| 10.1.0.3
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