|
Problem IC63275
|
Status: Closed |
REMOVING UNUSED COLUMNS FROM UNION ALL VIEW TO IMPROVE QUERY PERFORMANCE |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
DB2 may add internal columns to represent a key to uniquely
identify each row in a Union All view
in query optimization class 5 and 7. When the internal columns
are later considered not useful,
DB2 does not remove those columns. As a result, it could prevent
further query rewrites. |
| Problem Summary: |
DB2 may add internal columns to represent a key to uniquely
identify each row in a Union All view
in query optimization class 5 and 7. When the internal columns
are later considered not useful,
DB2 does not remove those columns. As a result, it could prevent
further query rewrites. |
| Local Fix: |
Use query optimization class 9 by issuing the following
statement
SET CURRENT QUERY OPTIMIZATION 9 |
| 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 |
This APAR is first fixed on the DB2 V9.7 Fixpack 1 |
| Workaround |
Use query optimization class 9 by issuing the following
statement
SET CURRENT QUERY OPTIMIZATION 9 |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 19.09.2009
15.01.2010
15.01.2010 |
| 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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