|
Problem IC81859
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Status: Closed |
ESTIMATED CARDINALITY OF UNNEST FUNCTION FOR ARRAY DATATYPE IS NOT USED DURING QUERY PLANNING |
| product: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problem description: |
The DB2 optimizer uses the maximum cardinality of an array
during plan generation. In many cases the maximum cardinality is
not a good indicator of the real array size, especially when
arrays are used in stored procedures or packages. As a result,
queries that use the UNNEST function with an array as input may
have poor plans due to the high maximum array cardinality. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* All users on DB2 v97 FP5 and earlier *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 v97 FP6 *
**************************************************************** |
| Local Fix: |
As a workaround, the user may specify an estimated cardinality
for the array by updating the statistics of the array cast
function in SYSSTAT.ROUTINES table:
db2 "update sysstat.routines set
cardinality=<cardinality_of_array> where
routineschema='<schema_name_of_array>' and
routinename='<array_name>'"
Dynamic statements will use the new cardinality at the next
compile.
Static packages will need to be rebound to use the new
cardinality. |
| 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 v97 FP6 |
| Workaround |
not known / see Local fix |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC84502 IC84565
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 06.03.2012
26.06.2012
26.06.2012 |
| 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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