|
Problem IC62120
|
Status: Closed |
DB2 MAY ISSUE SQL0901N EXECUTING A QUERY CONTAINING AN SQL UDF USED WITH A UNION ALL |
| product: |
DB2 FOR LUW / DB2FORLUW / 950 - DB2 |
| Problem description: |
An SQL0901N may be issued when executing a query an SQL UDF that
takes as input the output of a UNION ALL (UA) view or subselect.
The following conditions must be satisfied for the scenario to
occur:
- The UDF must be non-atomic
- The output data-type of the SQL UDF must be a VARCHAR or
VARGRAPHIC
- The maximum length of the output expression of the UDF must be
strictly less than the length of the output data-type of the UDF
- The UDF must use the output columns of a UA as its input
- The UDF must form the input to a subselect
- The output column of the subselect derived from the UDF must
be used in a GROUP BY clause
An example scenario follows:
-- Table DDL
CREATE TABLE T(DRIVER_C CHAR(2), DUMMY_C INT);
-- SQL UDF DDL
CREATE FUNCTION DUMMY_FN (INPUT_C VARCHAR(2))
RETURNS VARCHAR(20)
LANGUAGE SQL
DETERMINISTIC
NO EXTERNAL ACTION
RETURN CASE WHEN INPUT_C = 'AA' THEN 'VC-19-CNST-LT-VC-20' ELSE
'BB'
END
;
-- Query that will issue the SQL0901N
SELECT DRIVER_C,
SUM(DUMMY_C)
FROM
( SELECT DUMMY(DRIVER_C), DUMMY_C FROM
(
SELECT DRIVER_C,
DUMMY_C
FROM T
UNION ALL
SELECT DRIVER_C,
DUMMY_C
FROM T
) AS UA (DRIVER_C, DUMMY_C)
) AS SELSTAR (DRIVER_C, DUMMY_C)
GROUP BY DRIVER_C
;
-- SQLCODE issued
SQL0901N The SQL statement failed because of a non-severe
system error.
Subsequent SQL statements can be processed. (Reason "Describe:
Invalid svar
len".) SQLSTATE=58004
This problem will be first fixed in DB2 Version 9.1 Fix Pack 8
and DB2 Version 9.5 Fix Pack 5. |
| Problem Summary: |
****************************************************************
* USERS AFFECTED: *
* EE or EEE *
****************************************************************
* PROBLEM DESCRIPTION: *
* See Error Description. *
****************************************************************
* RECOMMENDATION: *
* Upgrade to DB2 Version 9.5 Fix Pack 5. *
**************************************************************** |
| Local Fix: |
- Reduce the value of the CURRENT QUERY OPTIMIZATION special
register to 0.
- Manually rewrite the query in question to workaround the
issue. For example, the query above may be semantically
equivalently rewritten to:
SELECT DRIVER_C,
SUM(DUMMY_C)
FROM
( SELECT DUMMY(DRIVER_C),
DUMMY_C
FROM T
UNION ALL
SELECT DUMMY(DRIVER_C),
DUMMY_C
FROM T
) AS UA (DRIVER_C, DUMMY_C)
GROUP BY DRIVER_C
; |
| available fix packs: |
DB2 Version 9.5 Fix Pack 5 for Linux, UNIX, and Windows
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 |
Problem was first fixed in DB2 Version 9.5 Fix Pack 5. |
| Workaround |
not known / see Local fix |
| Timestamps |
Date - problem reported :
Date - problem closed :
Date - last modified :
| 21.07.2009
19.02.2010
19.02.2010 |
| Problem solved at the following versions (IBM BugInfos) |
9.5.FP5
|
| Problem solved according to the fixlist(s) of the following version(s) |
| 9.5.0.5
|
 |
