A fix is available
APAR status
Closed as program error.
Error description
AN INCORRECT OUTPUT WITH ONLY 1 ROW INSTEAD OF AN EXPECTED OUTPUT WITH MANY ROWS RETURNED FOR A QUERY WITH AN INDEX WITH UNIQUE WHERE NOT NULL CHARACTERISTICS, AND BOTH ISNULL PREDICATE & JOIN PREDICATE ON A SAME COLUMN ZSA2
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * * All users of Db2 12 executing the * * queries with ON clause and with * * ISNULL predicate in the WHERE * * clause. * **************************************************************** * PROBLEM DESCRIPTION: * * Incorrectout may occur for the * * queries with ON predicates and * * with ISNULL predicate in WHERE. * * * * For the queries above, * * (1) The ON predicate and the * * ISNULL predicate are on the * * same column, and * * (2) There is a UWNN index on * * the column in (1), and * * (3) The index in (2) is used * * * * When the conditions above are * * met, INCORRECTOUT may occur. * **************************************************************** * RECOMMENDATION: * * Apply corrective PTF when available * **************************************************************** Incorrectout may occur for the queries with ON predicates and with ISNULL predicate in WHERE. For the queries above, (1) The ON predicate and the ISNULL predicate are on the same column, and (2) There is a UWNN index on the column in (1), and (3) The index in (2) is used When the conditions above are met, INCORRECTOUT may occur. For example of the following query SELECT T1.C1, T1.C4, T2.C1 FROM T1 LEFT OUTER JOIN T2 ON T1.C1 = T2.C1 WHERE T1.C1 IS NULL AND 0 = 0 WITH UR ; CREATE UNIQUE WHERE NOT NULL INDEX IDX1_T1 ON T1 (C1 ASC) ; If the index IDX1_T1 is used on T1, INCORRECTOUT may occur. It's because DB2 may decide that to use the index IDX1_T1 can guarantee uniqueness.
Problem conclusion
The problem described above is fixed by recognizing the index column is covered by an ISNULL predicate thus can't guarantee uniqueness.
Temporary fix
Comments
APAR Information
APAR number
PI95824
Reported component name
DB2 OS/390 & Z/
Reported component ID
5740XYR00
Reported release
C10
Status
CLOSED PER
PE
NoPE
HIPER
NoHIPER
Special Attention
NoSpecatt / Xsystem
Submitted date
2018-03-27
Closed date
2018-06-19
Last modified date
2018-08-14
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI56691
Modules/Macros
DSNXOPRS
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RC10 PSY UI56691
UP18/07/06 P F807
Fix is available
Select the PTF appropriate for your component level. You will be required to sign in. Distribution on physical media is not available in all countries.
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Document Information
Modified date:
14 August 2018