DB2 - Problem description
Problem IT34308 | Status: Closed |
REPLICATED MQT MATCH MAY FAIL IN SOME SPECIFIC SITUATIONS | |
product: | |
DB2 FOR LUW / DB2FORLUW / B50 - DB2 | |
Problem description: | |
Replicated MQT match may fail when following conditions are met: - MQT's base table is joined with other table and nullability differs between columns on both sides of the join. - MQT's base table is referenced more than once in the query The source of the problem is a join predicate: ON mqtbt.a_id = t1.a_id AND Where: - mqtbt - MQT's base table - mqtbt.a_id is a nullable column and t1.a_id is non-nullable column. As a result of internal query rewrite, mqtbt.a_id becomes not nullable, but the same is not true for compensation built for MQT matching purpose. That difference in nullability prevents MQT match. | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * all * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to Db2 11.5.5.0 or higher * **************************************************************** | |
Local Fix: | |
A potential workaround could be to ensure that mqtbt.a_id and mqtbt.a_id do not differ in terms of nullability - make both columns nullable or both not-nullable. For columnar tables it would require table drop and recreation | |
Solution | |
Workaround | |
**************************************************************** * USERS AFFECTED: * * all * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to Db2 11.5.5.0 or higher * **************************************************************** | |
Comment | |
Upgrade to Db2 11.5.5.0 or higher | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 22.09.2020 20.11.2020 20.11.2020 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) |