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Problem IC70557
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Status: Closed |
REWRITE OR PREDICATE TO UNION IN NOT IN/IN SUBQUERY MAY CAUSE PERFORMANCE REGRESSION |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
When DB2 rewrites OR predicate to UNION to utilize an index scan
access in the context of a NOT IN or IN subquery and the
subquery has no reference to any column of the tables outside
the subquery. The result of the rewrite may cause DB2 to select
a suboptimal plan by choosing an access plan that repeats the
processing of the subquery for each row of the tables outside
the subquery. |
| Problem Summary: |
REWRITE OR PREDICATE TO UNION IN NOT IN/IN SUBQUERY MAY CAUSE
PERFORMANCE REGRESSION |
| Local Fix: |
|
| available fix packs: |
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 6 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 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 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
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| Solution |
Problem was first fixed in Version 9.7 FixPack 4 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 13.08.2010
02.05.2011
02.05.2011 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP4
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.4
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