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Problem IC83850
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Status: Geschlossen |
DB2 QUERY OPTIMIZER MIGHT CHOOSE A NON-OPTIMAL ACCESS PLAN FOR QUERIES INVOLVING JOINS ON SKEWED DATA |
| Produkt: |
DB2 FOR LUW / DB2FORLUW / 970 - DB2 |
| Problembeschreibung: |
This is an extension to IC71258. You might encounter this
problem if your SQL statement is not performing optimally, one
or more joins in the query are on columns with significant skew
in one side of the join, one of the columns in the join is
unique, but the non-unique side of the join covers a larger
domain of values. |
| Problem-Zusammenfassung: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 9.7 Fix Pack 7 *
**************************************************************** |
| Local-Fix: |
As described in IC71258, to solve this problem, a statistical
view can be created on the join, where applicable, to provide
the optimizer the appropriate information to account for the
skew. |
| verfügbare FixPacks: |
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
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| Lösung |
Problem was first fixed in Version 9.7 Fix Pack 7 |
| Workaround |
See Local Fix |
| Weitere Daten |
Datum - Problem gemeldet :
Datum - Problem geschlossen :
Datum - der letzten Änderung:
| 30.05.2012
20.11.2012
20.11.2012 |
| Problem behoben ab folgender Versionen (IBM BugInfos) |
9.7.FP7
|
| Problem behoben lt. FixList in der Version |
| 9.7.0.7
|
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