|
Problem IC88965
|
Status: Closed |
OPTIMIZER MIGHT CHOOSE A SUB-OPTIMAL ACCESS FOR TABLE WITH THE SAME SINGLE COLUMN RANGE PARTITIONING KEY AND DISTRIBUTION KEY |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
Description:
The optimizer might choose a table scan over an index access of
a range partitioned table in a database partitioned environment
under the following conditions:
- the table is range partitioned and hash distributed on the
same single column; e.g.
create table t1 (C1 date, ...) distribute by hash (C1)
partition by range (C1) (starting (minvalue) ending
('2010-12-31'), starting('2011-01-01') ending ('2011-01-31'),
...)
- the query contains an equality predicate on the column; e.g.
C1='2012-01-15'
- a partitioned index containing C1 in the key exists
This problem is more likely to occur for tables with a large
number of range partitions where the majority are empty. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* This problem is more likely to occur for tables with a large *
* number of range partitions where the majority are empty. *
****************************************************************
* PROBLEM DESCRIPTION: *
* Description: *
* The optimizer might choose a table scan over an index access *
* of *
* a range partitioned table in a database partitioned *
* environment *
* under the following conditions: *
* - the table is range partitioned and hash distributed on the *
* same single column; e.g. *
* create table t1 (C1 date, ...) distribute by hash (C1) *
* partition by range (C1) (starting (minvalue) ending *
* ('2010-12-31'), starting('2011-01-01') ending *
* ('2011-01-31'), *
* ...) *
* - the query contains an equality predicate on the column; *
* e.g. *
* C1='2012-01-15' *
* - a partitioned index containing C1 in the key exists *
* *
* This problem is more likely to occur for tables with a large *
* number of range partitions where the majority are empty. *
****************************************************************
* RECOMMENDATION: *
* Upgraded to DB2 version 9.7 fixpack 8. *
**************************************************************** |
| Local Fix: |
You can use an optimization guideline to produce an index
access. |
| available fix packs: |
DB2 Version 9.7 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 9a for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
|
| Workaround |
You can use an optimization guideline to produce an index
access. |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC91749
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 10.12.2012
02.04.2013
02.04.2013 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP8
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.8
|
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