DB2 - Problembeschreibung
Problem IC68451 | Status: Geschlossen |
DB2_ANTIJOIN, DB2 SHOULD CONVERT ELIGIBLE OUTER JOIN TO ANTIJOIN | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 980 - DB2 | |
Problembeschreibung: | |
To improve performance, when the registry variable DB2_ANTIJOIN is set to anything other than NO, DB2 should convert an eligible OUTER JOIN into an ANTIJOIN. To be eligible, all the following must be true: 1. The OUTER JOIN must have an IS NULL predicate on a column from the NULL producing side. If the column is not the join column then it must be marked NOT NULL. 2. Null producing side of the OUTER JOIN must be a base table with no local predicates except for the IS NULL predicate. 3. It is not a federated query. 4. The select clause of the query must not reference any column from the null producing side of the left outer join. example: select t1.* from t1 left outer join t2 on t1.c1 = t2.c1 where t2.c2 IS NULL. | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * All * **************************************************************** * PROBLEM DESCRIPTION: * * See problem description * **************************************************************** * RECOMMENDATION: * * Please upgrade to DB2 v9.8 fix pack 4 * **************************************************************** | |
Local-Fix: | |
verfügbare FixPacks: | |
DB2 Version 9.8 Fix Pack 4 for AIX and Linux | |
Lösung | |
Fix in DB2 v9.8 fix pack 4 | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 06.05.2010 14.02.2011 14.02.2011 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.8.FP4 | |
Problem behoben lt. FixList in der Version | |
9.8.0.4 |