home clear 64x64
en blue 200x116 de orange 200x116 info letter User
suche 36x36
Latest versionsfixlist
11.1.0.7 FixList
10.5.0.9 FixList
10.1.0.6 FixList
9.8.0.5 FixList
9.7.0.11 FixList
9.5.0.10 FixList
9.1.0.12 FixList
Have problems? - contact us.
Register for free anmeldung-x26
Contact form kontakt-x26

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
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 3a for Linux, UNIX, and Windows
DB2 Version 10.1 Fix Pack 6 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 FixList
10.1.0.3 FixList
10.1.0.4 FixList