DB2 - Problem description
Problem IT21083 | Status: Closed |
POOR PERFORMANCE WHEN FORCE_REPLICATED_MQT_MERGE IS SET | |
product: | |
DB2 FOR LUW / DB2FORLUW / A50 - DB2 | |
Problem description: | |
DB2 may show poor performance when following conditions are met: - Registry variable FORCE_REPLICATED_MQT_MERGE is set - There are replicated MQTs that can be matched - There is EXIST/IN subquery and/or  SELECT DISTINCT - There are joins on multiple tables or joins | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * ALL * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * Upgrade to Db2 10.5 Fix Pack 9 or higher * **************************************************************** | |
Local Fix: | |
1) Unset registry FORCE_REPLICATED_MQT_MERGE or 2) Using registry setting DB2COMOPT=NO_DEEPKEYPU or 2) If the query has EXIST/IN subquery, rewrite the query to convert the EXIST/IN into join. | |
Solution | |
First fixed in Db2 10.5 Fix Pack 9 | |
Workaround | |
not known / see Local fix | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 19.06.2017 29.09.2017 29.09.2017 |
Problem solved at the following versions (IBM BugInfos) | |
9.0. | |
Problem solved according to the fixlist(s) of the following version(s) |