|
Problem IT01085
|
Status: Closed |
SQL STATEMENT WITH UNCORRELATED SUBQUERY PREDICATE MIGHT RETURN INCORRECT RESULTS WHEN INTRA_PARALLEL IS ENABLED |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
An SQL statement that satisfies the following conditions might
return an incorrect result set containing values that do not
qualify the clauses in the WHERE clause when INTRA_PARALLEL is
enabled:
- the statement contains an uncorrelated subquery predicate
nested within an uncorrelated EXISTS subquery predicate
- the query optimizer converts the EXISTS subquery to a join
- the access plan generated by the optimizer is parallelized
The following is an example of a statement that satisfies the
above conditions
SELECT DISTINCT A1 FROM T1
WHERE EXISTS (SELECT A2 FROM T2 WHERE B2 <> ALL (SELECT B3 FROM
T3 WHERE A3 BETWEEN 1 and 10); |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All users *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 version 9.7.0.10. *
**************************************************************** |
| Local Fix: |
Disable INTRA_PARALLEL for the problematic statement by setting
the CURRENT DEGREE special register to 1. |
| Solution |
The problem is first fixed in DB2 version 9.7.0.10. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 16.04.2014
08.12.2014
17.02.2015 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.0.10
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.10
|
 |
