DB2 - Problem description
| Problem IT00482 | Status: Closed |
DB2 OPTIMIZER CAN CHOOSE A NON-OPTIMAL BLOCK INDEX TO ACCESS MDC TABLE WHEN THE BLOCK INDEXES HAVE ONLY 1 LEVEL | |
| product: | |
DB2 FOR LUW / DB2FORLUW / A10 - DB2 | |
| Problem description: | |
When a MDC table has more than one dimensions, and when the block indexes have only 1 level, the optimizer might choose a block index access that applies a predicate as index sargable rather than a more efficient block index access that applies the predicate as start-stop keys. For example, consider a query that references a MDC table that is organized by 3 columns (C1,C2,C3), and includes the predicate C2=1. The predicate is applied as index sargable on the index access of the block index on (C1, C2, C3) (refer to hereafter as index A) whereas it is applied as a start-stop key on the index access of the block index on (C2) (refer to hereafter as index B). The optimizer might choose an access path using index A rather than index B. | |
| Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * All * **************************************************************** * PROBLEM DESCRIPTION: * * See Error Description * **************************************************************** * RECOMMENDATION: * * upgrade to DB2 Version 10.1 Fix Pack 4. * **************************************************************** | |
| Local Fix: | |
Use optimization profile to force the desired index access. | |
| available fix packs: | |
DB2 Version 10.1 Fix Pack 4 for Linux, UNIX, and Windows | |
| Solution | |
First fixed in DB2 Version 10.1 Fix Pack 4. | |
| Workaround | |
not known / see Local fix | |
| Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 21.03.2014 02.06.2014 02.06.2014 |
| Problem solved at the following versions (IBM BugInfos) | |
| Problem solved according to the fixlist(s) of the following version(s) | |
| 10.1.0.4 |
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