DB2 - Problem description
| Problem IT04236 | Status: Closed |
SQL STATEMENT WITH REPARTITIONED JOINS MIGHT RETURN INCORRECT RESULTS IN A DPF SYSTEM | |
| product: | |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 | |
| Problem description: | |
A complex SQL statement, requiring repartitioned joins in a DPF system, might produce wrong results if the following conditions are met: - The SQL statement includes two or more joins that are not collocated - At least one of the joins chosen by the optimizer is a repartitioned join, identifiable by the presence of a TQ operator somewhere below both inputs to the join - The join columns are of short-string type (CHAR, VARCHAR) with differing lengths. Note that the presence of these conditions does not always lead to incorrect results. | |
| Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * Database partitioning feature * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to DB2 version 10.1.0.5. * **************************************************************** | |
| Local Fix: | |
You can attempt to avoid the repartition join by creating one or more materialized query tables (MQT) on each table referenced in the join, where the MQT is defined with a hash distribution key on the join columns. | |
| Solution | |
The problem was first fixed in DB2 version 10.1.0.5. | |
| Workaround | |
not known / see Local fix | |
| Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 05.09.2014 10.07.2015 10.07.2015 |
| Problem solved at the following versions (IBM BugInfos) | |
| Problem solved according to the fixlist(s) of the following version(s) | |
| 10.1.0.5 |
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