Previous Topic: When to UseNext Topic: CXXMAINT ALTER DBCS (Activating DBCS Support)


How to Use

The MUF must be active when you execute this command. Execute DBUTLTY with the command:

►►─ CXXMAINT OPTION=ALTER,CXXENQ= ─┬─ LOCAL ◄ ─┬──────────────────────────────►◄
                                   └─ SYSPLEX ─┘

Command

CXXMAINT

Invokes the function for Directory maintenance.

Required Keywords

OPTION=ALTER

Requests the CXXMAINT ALTER option.

,CXXENQ=

Specifies the Directory (CXX) locking mode.

CXXENQ=LOCAL specifies that the Directory is locked only on the MVS image where the code is executing.

Note: We strongly recommend that each CXX name in the local z/OS environment be unique.

CXXENQ=SYSPLEX specifies that the locking of the Directory is done on all MVS images in the Sysplex where the code is executing.

Note: We strongly recommend that each CXX name in the entire Sysplex be unique.

Sysplex locking has more overhead than local locking. If the MUF jobs, Single User jobs, and DBUTLTY jobs that open the Directory locally execute on the same MVS image, Sysplex locking is not necessary.

If the Directory is used with local locking on more than one MVS image, it is possible that return code 67 (CXX INTERLOCK) could be generated, due to the DASD protection done after the ENQ has timed out (because of slowness in the image with the code executing that owns the lock). Sysplex locking is preferable, however, to random occurrences of return code 67. Therefore, we recommend CXXENQ=SYSPLEX for sites executing for this Directory on more than one MVS image.

With this option, the Sysplex ENQ is exclusively used to protect the CXX, and the DASD locking is disabled. This prevents any possible occurrence of a return code 67. It requires that the MUF and all DBUTLTY functions execute in the same Sysplex. This option should be considered as being required if running as part of a MUFplex to ensure full protection from a return code 67.

Valid Entries:

LOCAL or SYSPLEX

Default Value:

(No default)