|
Problem IC63747
|
Status: Closed |
SELECT DISTINCT WITH LANGUAGE AWARE COLLATION SEQUENCE WITH EO S1 ATTRIBUTE MAY RETURN WRONG RESULTS |
| product: |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 |
| Problem description: |
In a unicode database which was created with a language aware
collation sequence, like "UCA500R1_LROOT_AN_CX_EO_FX_HX_NX_S1"
a SELECT DISTINCT may return wrong results.
The problem is that despite attributes "EO S1" are specified,
which should respect case sensitivity, a string may be sorted as
a duplicate and therefore may be missing from the result set.
This problem happens only if the case difference is after the
7th character.
For example suppose 5 rows containing the column values:
Achter de Hoven
Achter de Hoven
Achter De Hoven
Achter de Hoven
Achter de Hovenstraat
Then a "select distinct(column) ..." returns just:
Achter de Hoven
Achter de Hovenstraat
which is wrong because "Achter De Hoven" is missing. The case
sensitivity was not respected. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* ALL *
****************************************************************
* PROBLEM DESCRIPTION: *
* In a unicode database which was created with a language *
* aware collation sequence, like *
* "UCA500R1_LROOT_AN_CX_EO_FX_HX_NX_S1" *
* a SELECT DISTINCT may return wrong results. *
* *
* The problem is that despite attributes "EO S1" are *
* specified, which should respect case sensitivity, a string *
* may be *
* sorted as a duplicate and therefore may be missing from the *
* result *
* set. *
* *
* This problem happens only if the case difference is after *
* the 7th character. *
* *
* For example suppose 5 rows containing the column values: *
* *
* Achter de Hoven *
* *
* Achter de Hoven *
* *
* Achter De Hoven *
* *
* Achter de Hoven *
* *
* Achter de Hovenstraat *
* *
* *
* *
* Then a "select distinct(column) ..." returns just: *
* *
* Achter de Hoven *
* *
* Achter de Hovenstraat *
* *
* which is wrong because "Achter De Hoven" is missing. The *
* case sensitivity was not respected. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 UDB Version 9.5 FixPak 6 *
**************************************************************** |
| Local Fix: |
Either:
Creating an index on the column allows select distinct to return
the correct result. Verify that optimizer chooses the index.
Or:
Avoid a BINSORT used by DB2 internally by setting registry
variable:
db2set DB2_BINSORT=off |
| available fix packs: |
DB2 Version 9.5 Fix Pack 6a for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 7 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 8 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 9 for Linux, UNIX, and Windows
DB2 Version 9.5 Fix Pack 10 for Linux, UNIX, and Windows
|
| Solution |
First fixed in DB2 UDB Version 9.5 FixPak 6 |
| Workaround |
see LOCAL FIX. |
| BUG-Tracking |
forerunner : APAR is sysrouted TO one or more of the following: IC63837
follow-up : |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 15.10.2009
01.09.2010
01.09.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.5.
|
| Problem solved according to the fixlist(s) of the following version(s) |
