DB2 - Problembeschreibung
Problem IC67741 | Status: Geschlossen |
POSSIBLE INCORRECT RESULTS OPTIMIZING A <COLUMN> = ? PREDICATE ON A UNION ALL VIEW USED AS A COMMON SUB-EXPRESSION | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 | |
Problembeschreibung: | |
Incorrect results may occur during the optimization of a Union All view (UA) that is used as a common sub-expression (CSE) and has predicate(s) applied on it. The conditions for such a scenario are: 1) Query contains a UA (UA1) over another UA (UA2) and UA2 is used in both legs of UA1 (making it a CSE) 2) The legs of UA2 are simple selects over base-tables (BT) 3) The legs of UA2 have no predicates or simple equi-join or range-join local predicates 4) Each BT used in UA2 has equi-join check constraints defined on it 5) Either leg of UA1 has one or more <column> = ? predicate (PARAMPRD) 6) The column referenced in PARAMPRD is an output column of UA2 7) All column(s) referenced in PARAMPRD(s) source directly from BTs and have equi-join check constraints defined on them 8) The parameter marker referenced in PARAMPRD is bound to a value VAL1. 9) VAL1 is different from the check constraint value of the column from the largest BT under UA2 that is referenced in PARAMPRD | |
Problem-Zusammenfassung: | |
Users Affected: Specific to a union all view used as a common sub-expression. Problem Description: POSSIBLE INCORRECT RESULTS OPTIMIZING A <COLUMN> = ? PREDICATE ON A UNION ALL VIEW USED AS A COMMON SUB-EXPRESSION Problem Summary: See above. | |
Local-Fix: | |
Lower the query optimization class to a value less than 5. This can be done either by altering the CURRENT QUERY OPTIMIZATION special register or by altering the DFT_QUERYOPT database configuration parameter. | |
verfügbare FixPacks: | |
DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows | |
Lösung | |
Problem was first fixed in Version 9.5 FixPak 6 | |
Workaround | |
Lower the query optimization class to a value less than 5. This can be done either by altering the CURRENT QUERY OPTIMIZATION special register or by altering the DFT_QUERYOPT database configuration parameter. | |
Bug-Verfolgung | |
Vorgänger : APAR is sysrouted TO one or more of the following: IC68260 IC68261 Nachfolger : | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 08.04.2010 07.10.2010 07.10.2010 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
9.5. | |
Problem behoben lt. FixList in der Version |