|
Problem IC63255
|
Status: Closed |
USAGE OF MQTENFORCE GUIDELINE COULD CAUSE THE OPTIMIZER TO FAVOUR A SUB-OPTIMAL STARJOIN PLAN |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
With an Optimizer profile enabled and containing a guideline
with
the MQTENFORCE element, the Optimizer may favour a sub-optimal
star-join plan.
This can occur if the there are matchable non-group-by
Materialized Query Table(s) (MQT) present in the schema and are
specified for enforcement either explicitly using the NAME
attribute or generally via the TYPE attribute of the MQTENFORCE
guideline element. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* EE or EEE *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 9.7 Fix Pack 1. *
**************************************************************** |
| Local Fix: |
1) Disable the Optimizer profile
2) Specify a better plan using an Optimizer hint
3) When a range of MQTs is specified using the MQTENFORCE
element's TYPE attribute, explicitly specify all MQT(s) except
the problematic one using the MQTENFORCE element's NAME
attribute |
| available fix packs: |
DB2 Version 9.7 Fix Pack 1 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 2 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 5 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 6 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 10 for Linux, UNIX, and Windows
|
| Solution |
Problem was first fixed in DB2 Version 9.7 Fix Pack 1. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 17.09.2009
19.02.2010
19.02.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP1
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.1
|
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