|
Problem IC78403
|
Status: Closed |
DB2 OPTIMIZER CAN CHOOSE A SUB-OPTIMAL PLAN FOR A TABLE THAT HAS A HIGH ROWS-PER-PAGE NUMBER |
| product: |
DB2 FOR LUW / DB2FORLUW / 910 - DB2 |
| Problem description: |
When a table has a high rows-per-page number, DB2 optimizer can
be too conservative with the estimate and as a result,
prefetching may not occur for a IXSCAN-FETCH operation on such a
table, even when the index has a high cluster ratio. This can
result in a sub-optimal query plan. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Problem Description above. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 9.1 Fix Pack 11. *
**************************************************************** |
| Local Fix: |
|
| available fix packs: |
DB2 Version 9.1 Fix Pack 11 for Linux, UNIX and Windows
DB2 Version 9.1 Fix Pack 12 for Linux, UNIX and Windows
|
| Solution |
First Fixed in Version 9.1 Fix Pack 11. |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC78430 IC78431
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 30.08.2011
23.12.2011
23.12.2011 |
| Problem solved at the following versions (IBM BugInfos) |
9.1.FP11
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.1.0.11
|
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