DB2 - Problembeschreibung
Problem IC63255 | Status: Geschlossen |
USAGE OF MQTENFORCE GUIDELINE COULD CAUSE THE OPTIMIZER TO FAVOUR A SUB-OPTIMAL STARJOIN PLAN | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 | |
Problembeschreibung: | |
With an Optimizer profile enabled and containing a guideline with the MQTENFORCE element, the Optimizer may favour a sub-optimal star-join plan. This can occur if the there are matchable non-group-by Materialized Query Table(s) (MQT) present in the schema and are specified for enforcement either explicitly using the NAME attribute or generally via the TYPE attribute of the MQTENFORCE guideline element. | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * EE or EEE * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description. * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 Version 9.7 Fix Pack 1. * **************************************************************** | |
Local-Fix: | |
1) Disable the Optimizer profile 2) Specify a better plan using an Optimizer hint 3) When a range of MQTs is specified using the MQTENFORCE element's TYPE attribute, explicitly specify all MQT(s) except the problematic one using the MQTENFORCE element's NAME attribute | |
verfügbare FixPacks: | |
DB2 Version 9.7 Fix Pack 1 for Linux, UNIX, and Windows | |
Lösung | |
Problem was first fixed in DB2 Version 9.7 Fix Pack 1. | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 17.09.2009 19.02.2010 19.02.2010 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.7.FP1 | |
Problem behoben lt. FixList in der Version | |
9.7.0.1 |