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Problem IC99319
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Status: Closed |
SQL STATEMENT WITH ORDERED COLUMN GROUP OR PREDICATES MIGHT RETURN INCORRECT RESULT SET WHEN JUMP SCAN USED |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
An SQL statement that includes one or more ordered column group
OR predicates might return an incorrect result set if the DB2
optimizer chooses a jump scan index access that applies the OR
predicate as index range delimiting predicates for more
efficient access.
For example, the following predicate has an ordered column group
OR predicate that defines a column group (a1, a2, a3) and an
inclusive condition on the key values (1, 2, 3).
(a1>1) or (a1=1 and a2>2) or (a1=1 and a2=2 and a3>=3)
If there is an index (a1 asc, a2 asc, a3 asc), then the
optimizer can apply the composite inclusive key for better
filtering and minimal data read from the index. |
| Problem Summary: |
Users affected: All users
Problem Description: see error description |
| Local Fix: |
You can avoid the problem by disabling jump scan using the
JUMPSCAN option of the DB2_REDUCED_OPTIMIZATION variable:
DB2_REDUCED_OPTIMIZATION="JUMPSCAN OFF".
You can also use the REGISTRY optimization guideline element to
set this at the application or statement level. |
| available fix packs: |
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 for Linux, UNIX, and Windows
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| Solution |
The problem is first fixed in DB2 UDB
version 10.1 fix pack 4 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 12.02.2014
18.07.2014
18.07.2014 |
| Problem solved at the following versions (IBM BugInfos) |
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| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.4
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