DB2 - Problembeschreibung
Problem IC94359 | Status: Geschlossen |
QUERY WITH EXISTS OR EXISTS PREDICATES MIGHT HAVE PERFORMANCE DEGRADATION | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 | |
Problembeschreibung: | |
Under rare scenarios, DB2 might produce a sub-optimal query plan if the following conditions are satisfied: 1. There are 3 or more inner joined tables in the query (say T1, T2, T3) 2. The query contains a OR predicate with two or more subterms consisting of subqueries 3. The subqueries can be of type Exists, Not Exists or IN 4. One of the tables (T1) in the inner join is also the source for the subquery. 5. There is only a single join predicate between Table T1 and one of the other tables (T2) 6. (optional) There may be local predicates on tables not directly connect to T1. eg. select * from t1, t2, t3 where t1.c1 = t2.c1 and t2.c2 = t3.c2 and t3.c1 = 1 and exists (select c1 from T4 where t1.c2 = t4.c2) or exists (select c1 from T5 where t1.c2 = t5.c2); | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * All * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 version 101 fixpack 3 * **************************************************************** | |
Local-Fix: | |
db2set -im DB2COMPOPT=327685,524288 | |
verfügbare FixPacks: | |
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows | |
Lösung | |
The problem is fixed in DB2 version 101 fixpack 3 | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 24.07.2013 24.10.2013 24.10.2013 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
Problem behoben lt. FixList in der Version | |
10.1.0.3 | |
10.1.0.3 |