DB2 - Problembeschreibung
| Problem IC84454 | Status: Geschlossen |
EQUALITY JOIN PREDICATES PUSHED DOWN THRU OLAP FUNCTION FORMING A CORRELATION MAY CAUSE A PERFORMANCE DEGRADATION. | |
| Produkt: | |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 | |
| Problembeschreibung: | |
Equality join predicates may be pushed down thru an OLAP
function.
The columns in the join predicates are required to be a superset
of a unique index (or a primary key). The join predicates then
will
form a correlation, resulting in limiting the only join method
eligible
be the NLJOIN. This could cause a performance degradation.
An indicator that a user has hit this problem is to look at the
Optimized Statement of the db2exfmt output.
(SELECT ..., <func>(<col> OVER (PARTITION NY <col>,...), ...
FROM Q#3, ...
WHERE Q#3.<col> = Q#2.<col>
) AS Q#1,
<table> AS Q#2, ...
If a correlated join predicate such as Q#3.<col> = Q#2.<col> is
seen,
this SQL statement may hit this problem. | |
| Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * DB2 UDB Version 10.1 * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to Version 10.1 FixPack 1. * **************************************************************** | |
| Local-Fix: | |
| verfügbare FixPacks: | |
DB2 Version 10.1 Fix Pack 1 for Linux, UNIX, and Windows | |
| Lösung | |
Problem was first fixed in DB2 UDB Version 10.1 FixPack 1. | |
| Workaround | |
keiner bekannt / siehe Local-Fix | |
| Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 14.06.2012 03.11.2012 03.11.2012 |
| Problem behoben ab folgender Versionen (IBM BugInfos) | |
| Problem behoben lt. FixList in der Version | |
| 10.1.0.1 |
|
| 10.5.0.1 |
|