|
Problem IC80451
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Status: Closed |
OPTIMIZER'S ESTIMATED CARDINALITY INCORRECTLY DROPS AT TQ OPERATOR WHEN QUERY CONTAINS NODENUMBER PREDICATE |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
If a query contains a predicate on NODENUMBER which restricts
to a single node (such as NODENUMBER(T1.C1) = <const>), the
optimizer may incorrectly reduce the estimated cardinality at
certain TQ operators in the access plan. This can potentially
lead to a suboptimal plan choice. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* Queries using a nodenumber predicate in a DPF envinronment *
* may be impacted *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 9.7 Fix Pack 6 *
**************************************************************** |
| Local Fix: |
If the TQ cardinality drops at the TQ of a base table,
replicating the base table may correct the cardinality, but
this depends on the optimizer choosing to use the replicated
table based on cost. |
| available fix packs: |
DB2 Version 9.7 Fix Pack 6 for Linux, UNIX, and Windows
DB2 Version 9.7 Fix Pack 7 for Linux, UNIX, and Windows
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 |
First fixed in DB2 Version 9.7 Fix Pack 6 |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC84497
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 15.12.2011
07.06.2012
07.06.2012 |
| Problem solved at the following versions (IBM BugInfos) |
9.7.FP6
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.7.0.6
|
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