DB2 - Problembeschreibung
Problem IT03293 | Status: Geschlossen |
IN DPF ENVIRONMENT THE DB2 OPTIMIZER MIGHT PRODUCE A NON-OPTIMAL ACCESS PLAN WHEN DB2_WORKLOAD=SAP | |
Produkt: | |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 | |
Problembeschreibung: | |
The DB2 optimizer might produce a non-optimal access plan for SQL statements that are eligible for star-join optimizations when the DB2_WORKLOAD=SAP aggregate registry variable is set in a partitioned database environment. When this problem is encountered, the optimizer will produce a non-optimal access plan consisting of a stack of hash join (HSJOIN) operators with multiple large dimension tables, located in a single database partition, that are broadcast to complete the joins. You can gather an EXPLAIN of the affected queries to confirm this pattern of operations in the access plan. | |
Problem-Zusammenfassung: | |
**************************************************************** * USERS AFFECTED: * * All * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description above. * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 Version 10.5 Fixpack 3. * **************************************************************** | |
Local-Fix: | |
You can try any of the following options for the tables located in a single database partition: 1) Redistribute the table across multiple partitions, located in the same partition group as the fact table, using the join columns as the distribution key. This can also be accomplished as a temporary fix by creating a MQT as (select * from table) that is located in the same partition group as the fact table 2) Create a replicated MQT of the table, locating the MQT in the same partition group as the fact table | |
Lösung | |
First fixed in Version 10.5 Fixpack 3. | |
Workaround | |
keiner bekannt / siehe Local-Fix | |
Weitere Daten | |
Datum - Problem gemeldet : Datum - Problem geschlossen : Datum - der letzten Änderung: | 22.07.2014 19.02.2015 19.02.2015 |
Problem behoben ab folgender Versionen (IBM BugInfos) | |
Problem behoben lt. FixList in der Version | |
10.5.0.4 |