A fix is available
APAR status
Closed as program error.
Error description
Db2 12 serviceability for influencing access path selection. For SQL statements with complex inner and outer joins, Db2 12 uses an aggressive approach to reduce join work files. However, this approach may cause performance degradation in some cases. Keywords: SQLPERFORMANCE SQLACCESSPATH SQLJOIN SQLOUTER SQLOUTERJOIN
Local fix
Problem summary
**************************************************************** * USERS AFFECTED: * * All Db2 V12 for z/OS users running SQL * * statements with complex inner and outer * * joins * **************************************************************** * PROBLEM DESCRIPTION: * * Db2 12 hidden zparm support for * * disabling aggressive approach to * * reduce join work files for SQL * * statements with complex inner and * * outer joins. * **************************************************************** * RECOMMENDATION: * * Apply corrective PTF when available * **************************************************************** For SQL statements with complex inner and outer joins, Db2 12 uses an aggressive approach to reduce join work files. With few exceptions, this aggressive approach should provide significant performance improvements. On the rare occasion that a regression does occur, IBM support may request for this new feature to be disabled. The hidden zparm should not be changed without consulting IBM support first. This is a serviceability enhancement to disable the aggressive approach.
Problem conclusion
Serviceability APAR only. Keywords: SQLPERFORMANCE SQLACCESSPATH SQLOUTERJOIN SQLFULLJOIN SQLOUTER SQLFULL SQLJOIN SQLLEFTJOIN SQLLEFT SQLRIGHTJOIN SQLRIGHT
Temporary fix
Comments
APAR Information
APAR number
PH29666
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
2020-09-18
Closed date
2020-10-01
Last modified date
2020-11-02
APAR is sysrouted FROM one or more of the following:
APAR is sysrouted TO one or more of the following:
UI71877
Modules/Macros
DSNXOMQB DSNDQWPZ DSNXOMPS DSNDSPRM DSN6SPRC
Fix information
Fixed component name
DB2 OS/390 & Z/
Fixed component ID
5740XYR00
Applicable component levels
RC10 PSY UI71877
UP20/10/09 P F010
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.
[{"Line of Business":{"code":"LOB10","label":"Data and AI"},"Business Unit":{"code":"BU059","label":"IBM Software w\/o TPS"},"Product":{"code":"SSEPEK","label":"Db2 for z\/OS"},"Platform":[{"code":"PF025","label":"Platform Independent"}],"Version":"12.0"}]
Document Information
Modified date:
31 March 2021