DB2 - Problembeschreibung
Problem IT11543 | Status: Geschlossen |
CORRELATED SUBQUERIES IN UPDATE AND DELETE OPERATIONS ON COLUMN ORGANIZED TABLES RESULT IN PERFORMANCE DEGRADATION | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 | |
Problembeschreibung: | |
Under rare scenario, DB2 might produce a suboptimal plan for SQL queries leading to performance degradation. The problem can be seen for the following conditions: 1) The query is an UPDATE or DELETE 2) The query references a scalar subquery either within the SET clause of the UPDATE or the WHERE clause of the DELETE statement 3) The scalar subquery has one or more correlated predicates 4) There is no primary key or unique key on the set of predicates in the scalar subquery eg. UPDATE t1 set t1.c1 = (select c1 from t2 where t1.c2 = t2.c2) where exists (select c1 from t2 where t2.c2 = t1.c2); DELETE from t1 where t1.c1 = (select c1 from t2 where t2.c2 = t1.c2); | |
Problem-Zusammenfassung: | |
Local-Fix: | |
Lösung | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 02.10.2015 05.02.2016 05.02.2016 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
Problem behoben lt. FixList in der Version | |
10.5.0.7 |