Utility Statements › REORG › JCL Considerations

JCL Considerations

The REORG command must be submitted through the batch command facility. The JCL to execute the facility must include statements to define:

• The standard BCF JCL statements.
• A RORGCTL file. It is a fixed-length, LRECL 8192, unblocked BDAM file that is initialized during setup and read and updated by subsequent and parallel jobs.
• An optional RORGJCL file that references a card-image file containing JCL that is automatically submitted by REORG. This file must be fixed or fixed blocked with an LRECL of 80.
• The files containing the source areas and their dependent areas for the unload phase if dynamic database allocation is not being used to reference them through the source DMCL.
• The files containing the target areas for the RELOAD and REBUILD phases if dynamic database allocation is not being used to reference them through the target DMCL.
• The journal file(s), which can be dummied.
• The work files if dynamic work file allocation is not being used to reference them.

If performing parallel processing, do not specify any syntax that would cause the jobs to serialize.

• Do not specify DISP=OLD or DISP=NEW for database or work files. Specify DISP=SHR instead. If a file is new and must be created, create it prior to submitting any REORG jobs.
• DISP=OLD or DISP=NEW is acceptable for a file that is unique to a job. For example SYSLST, SYSOUT, or SYSJRNL are unique to a job. Sort files such as SORTWK01 and SORTMSG are also unique to a given job.

If you define the same DDNAMEs for the source and target database files, the database cannot be unloaded and reloaded in the same job. You must halt processing after the unload phase and then restart processing ensuring that the target files and not the source files are being referenced. Follow these general steps:

• Submit JCL for the unload phase. The source database files must be referenced in the REORG JCL and in JCL submitted from RORGJCL, unless using dynamic database file allocation.
• Use the STOP AFTER UNLOAD option to halt the REORG process after the unload phase.
• After all unload jobs have ended and the unload phase has completed, format the target database files if they have not already been formatted.
• Submit JCL for the reload phases. The submitted job and JCL submitted from RORGCTL must reference the target database files, unless using dynamic database file allocation.
• The submitted job must say STOP AFTER CLEANUP or STOP AFTER RELOAD to allow tasks in the reload phases to run.

Work files can be manually or dynamically allocated. Considering the number of work files needed, the use of dynamic work file allocation is recommended. A CREATE DSMODEL must be coded in the SETUP job, or in the job that allocates the files to use dynamic allocation.

Note: When using CREATE DSMODEL statements, it is recommended that you force the batch command facility to terminate if an error is encountered. You do this by specifying a SET OPTIONS statement with the ON ERROR END clause. By forcing a termination, it ensures that REORG will not execute with incomplete data set models due to an error in a CREATE DSMODEL statement.

When manually allocating work files, you should run a preliminary REORG with the STOP AFTER SETUP option. This produces a report of all required work files. You must allocate these files prior to restarting the REORG process and include the necessary DD statements with DISP=SHR in the JCL that is submitted to restart processing and in the JCL in the RORGJCL file.

The RORGCTL file should be created prior to submitting the first REORG job, unless STOP AFTER SETUP is specified. REORG jobs running in parallel must specify DISP=SHR on this file, or they will serialize with each other on the DSNAME. If processing is stopped after SETUP, the SETUP job can create the file, but subsequent jobs must specify DISP=SHR.

Note: For more information about the generic JCL used to execute the batch command facility, see the chapter for your operating system in this guide.