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Problem IC94360
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Status: Closed |
QUERY CONTAINING EXISTENTIAL SUBQUERIES WITH MULTIPLE TABLES MIGHT HAVE PERFORMANCE DEGRADATION |
| product: |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 |
| Problem description: |
Under some scenarios, DB2 might exhibit a performance
degradation if the following conditions are true:
1. The query contains a OR predicate with two or more subterms
consisting of subqueries
2. The subqueries can be of type Exists, Not Exists or IN
3. One or more of these subqueries references more than 1 table
eg. Select c1, c2 from T1 where
Exists (select * from T2 where t1.c1 = T2.c1) OR
Not Exists (select c1 from T2, T3 where t2.c1 = t3.c1 and T2.c2
= T1.c2); |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 version 101 fixpack 3 *
**************************************************************** |
| Local Fix: |
db2set -im DB2COMPOPT=327685,524288 |
| 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
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| Solution |
Problem is first fixed in DB2 version 101 fixpack 3 |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 24.07.2013
24.10.2013
24.10.2013 |
| Problem solved at the following versions (IBM BugInfos) |
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 10.1.0.3
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 |
| 10.1.0.3
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