|
Problem IC65405
|
Status: Closed |
POSSIBLE PERFORMANCE REGRESSION FROM SCALAR SUBQUERY PUSH DOWN INTO OUTER JOIN |
| product: |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 |
| Problem description: |
A SQL staement containing a scalar subquery used in the context
of >=, >, <=, <, !=, or as an expression of other expression
rather than an equality predicate may be pushed down under an
Outer Join operation. If the whole expression results in an
expanding join because of the push down, it could potentially
degrade the performance of the statement. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* A SQL statement containing a scalar subquery used in the *
* context *
* of >=, >, <=, <, !=, or as an expression of other expression *
* *
* rather than an equality predicate may be pushed down under *
* an *
* Outer Join operation. If the whole expression results in an *
* *
* expanding join because of the push down, it could *
* potentially *
* degrade the performance of the statement. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 9.5 Fix Pack 6 *
**************************************************************** |
| Local Fix: |
Upgraded to DB2 Version 9.1 Fix Pack 9 |
| available fix packs: |
DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
First fixed in DB2 Version 9.5 Fix Pack 6 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 05.01.2010
17.05.2010
17.05.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.5.FP6
|
| Problem solved according to the fixlist(s) of the following version(s) |
