DB2 - Problem description
Problem IC90465 | Status: Closed |
PERFORMANCE DEGRADATION MIGHT BE NOTICED WITH NOT EXISTS SUBQUERY WITH MULTIPLE TABLES. | |
product: | |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 | |
Problem description: | |
Under some scenarios, DB2 might choose a suboptimal plan if the following conditions are true: 1. The query has a not exists subquery 2. The subquery contains 2 or more base tables 3. The correlated join predicate in the subquery has an index on the join column. | |
Problem Summary: | |
Under some scenarios, DB2 might choose a suboptimal plan if the following conditions are true: 1. The query has a not exists subquery 2. The subquery contains 2 or more base tables 3. The correlated join predicate in the subquery has an index on the join column. | |
Local Fix: | |
Disable AntiJoin by either : 1> db2set DB2_ANTIJOIN=NO -im 2> set up an optimization guideline to disable the antijoin for this specific query only. | |
available fix packs: | |
DB2 Version 10.1 Fix Pack 3 for Linux, UNIX, and Windows | |
Solution | |
First fixed in DB2 Version 10.1 Fix Pack 3. | |
Workaround | |
Disable AntiJoin by either : 1> db2set DB2_ANTIJOIN=NO -im 2> set up an optimization guideline to disable the antijoin for this specific query only. | |
BUG-Tracking | |
forerunner : APAR is sysrouted TO one or more of the following: IC95335 follow-up : | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 25.02.2013 06.05.2014 06.05.2014 |
Problem solved at the following versions (IBM BugInfos) | |
Problem solved according to the fixlist(s) of the following version(s) | |
10.1.0.3 | |
10.1.0.3 | |
10.1.0.4 |