Utility Statements › RELOAD › Usage

Usage

How to submit the RELOAD utility

You submit the RELOAD utility only through the batch command facility. You must run the batch command facility in local mode.

When to use RELOAD

Use the RELOAD utility to reload a database that has been unloaded by UNLOAD.

When reloading an SQL-defined database, the database files must be formatted using the FILE option of the FORMAT utility statement so that AREA and TABLE stamps are properly reloaded.

When not to use RELOAD

Do not use the RELOAD utility to load a new non-SQL-defined database; use the FASTLOAD utility.

Do not use the RELOAD utility to load a new SQL-defined database; use the LOAD utility.

Run RELOAD all at once or in steps

The reloading process has eight steps, which you can run one at a time or all together. Each step generates output for use by the next step. Four of the steps are sorts to prepare data for use by the following step.

You can run each step separately, in which case you can use your own sorting program. Alternatively, you can direct the RELOAD utility to do the sorting for you. If you run the steps as a single process, the RELOAD utility will do the sorting for you automatically.

When to run RELOAD in steps

The most common reason to run the RELOAD utility in steps is to cut the work into pieces, each piece requiring less time to run than the whole process.

You could also decide to run the RELOAD utility in steps in order to use your own sorting programs between the steps, or you can run the sort steps on a different machine than the one holding the database.

Mixed Page Groups

RELOAD cannot process mixed page groups and will issue an error message if mixed page groups are encountered. You must use multiple invocations of the utility to process different page groups.

RELOAD and ASF databases

If the RELOAD utility is to be run against an ASF data or definition area, see the CA IDMS ASF User Guide for more information.

Restarting IDMSDBL2, IDMSDBL3, or IDMSDBL4

If a problem arises while running IDMSDBL2 or IDMSDBL3, do not simply fix the cause of the problem and rerun the step. In addition to fixing the cause of the problem, you must do one of the following:

• Reinitialize the database and begin again at the IDMSDBL2 step
• If you backed up the database before running the step, you can run the step again, using the backup.

These steps change the database, and if a problem arises, you need to undo the changes before running a step over again.

If a non-data related problem occurs while running IDMSDBL4, you can restart the job without restoring. If the input file (SYS011) still exists, unlock the area and run the RELOAD utility from IDMSDBL4. Any updates previously performed by the run of IDMSDBL4 that abended will be overlayed by the updates in the restarted IDMSDBL4.

Note: For more information and help in deciding whether to run the RELOAD utility all at once or in steps, see the CA IDMS Database Administration Guide.

Data from UNLOAD is in SYS001, SYS002, SYS003, and RELDCTL

The information the RELOAD utility needs is in the SYS001, SYS002, SYS003, and RELDCTL files. UNLOAD knew these files as SYSPCH, SYS002, SYS003, and RELDCTL, respectively.

• The SYS001 file contains sort parameters.

  Note: If the RELOAD utility is started at a SORT step, in any mode, SYS001 should point to the sort parameters generated in a previous step.

• The SYS002 file contains the following:
  • Unloaded data from UNLOAD processing
  • Data to be loaded
  • Set membership information for each record
• The SYS003 file contains both system and user-owned index data from UNLOAD processing. If running in STEP mode, index data is not input until the SORT2 step.
• The RELDCTL file contains:
  • Set descriptor information
  • A control record containing subschema, segment, and DMCL information
  • Control information created during UNLOAD processing and used by RELOAD processing. If running in STEP mode, this file must be input to every step.

SORTEXIT and FROM/STEP

When using the FROM and STEP options with the SORTEXIT option, each pair of SORTn and DBLx steps are considered to be one step. If either half of the SORTn/DBLx is specified on a FROM or STEP option, processing will start with the SORTn step and the DBLx step will also be executed. For example:

• FROM IDMSDBL3 will start with step SORT3 and will continue to the end.
• STEP SORT3 will run steps SORT3 and IDMSDBL3.

SORTEXIT/REUSE WORKFILE restart considerations

Since SORTEXIT combines each SORTn step with the DBLx step that follows it, if a failure occurs in the DBLx step, a restart (if a restart is possible) must begin with the sort step and the input to the step will be resorted. Non-SORTEXIT mode will take longer to run but can be restarted after the sort in this case. Therefore, if restart time is more critical than normal runtime do not run the utility as a sortexit.

If the REUSE WORKFILE option is used with SORTEXIT, some input workfiles will be used as output files in the same step. Therefore, if these two options are used together and a failure occurs, the utility must be restarted from the beginning.

Workfile considerations for restarting a failed RELOAD

If the RELOAD command fails, depending on the reason for failure, restart the command at the failing step using the "FROM step-name" syntax. You can restart a step only if the input files to that step are intact and valid.

To prepare for a possible restart when running a one-step RELOAD, the intermediate work files should have a disposition that preserves the data set in the event of an abend, for example, "DISP=(NEW,CATLG,CATLG)."

To restart RELOAD at a particular step, the input files to that step must have a disposition to specify that the files already exist, for example, "DISP=OLD."

To determine which files were input to a given step see the "Intermediate Work File" tables under "JCL Considerations." Partially created output files should be deleted before you restart the job, and the original disposition should be used in the restart job, for example, "DISP=(NEW,CATLG,CATLG)."

The SYSPCH file contains sort parameter information for sort steps. It is an output file to IDMSDBLn steps but is not read unless restarting or running in step mode. So during a normal run the SYSPCH file should be treated as a normal output file, for example, "DISP=(NEW,CATLG,CATLG)." However, restarting is not as straightforward. If the previous job failed in an IDMSDBLx step, the SYSPCH file was an output file and should be deleted before restarting. But if the failure occurred in a SORTx step, the contents of the SYSPCH file should contain the same values that were input to the SORTx step. In this case the SYSPCH file should be preserved and defined as a SYS001 input file to the restart step.

When the SORTEXIT option is used, the SORTx and IDMSDBLx steps are combined. If a failure occurs in this mode, the SYSPCH file should normally be preserved and used as a SYS001 input file to the restart. However, there is a small window at the end of a IDMSDBLx step where the SYSPCH file is opened for output and new SORT parameters are written. If the job fails at this point, the entire SORTx/IDMSDBLx step must be restarted, but the SYSPCH file will not be valid as a SYS001 input file. In this case, the sort parameters must be recreated by hand or the job must be restarted at an earlier IDMSDBLx step if possible. One way to avoid this situation is to run in step mode when running SORTEXIT mode.

The RELDCTL data set is always an input file to the first step of a RELOAD whether being restarted or not.

REUSE WORKFILE considerations

Some tape volume management systems consider the reuse of a tape volume for second time output processing an error even in the same job and will not allow you to make this mistake. It results in rerunning the job over again without the REUSE option. You can sometimes avoid this by specifying a zero retention period for the tape output volume.

Intermediate work files

The following tables indicate which work files are created and read by the different utility steps depending on the use of the SORTEXIT and REUSE WORKFILE options.

How RELOAD works

The RELOAD utility consists of the following steps, which you can run separately or as a single operation:

Each step has input and output

Each step uses the output from an earlier step and generates output for use by the next step. The following table lists the input and output for each step:

* The sort parameters noted in the previous table are read from SYS001, as noted, only when you run the sort steps individually. If you run all steps together, or all steps from an intermediate restart (using FROM), the sort parameters are passed in-storage. If you restart from an abnormal termination, point the SYS001 file to the SYSPCH file of the last completed step.

Sort output after each step

If you run the RELOAD utility a step at a time, you must use the sort parameters in the SYSPCH file to sort the contents of the intermediate work files.

Sort the intermediate work files as follows:

Note: The generated sort parameters are insufficient for stand-alone sort programs under z/VSE. If you want to use your own sort program, you must add 'WORK=' parameters to specify more than one file whose contents are to be sorted.

DBLUEREX User Exit

RELOAD modules IDMSDBL2, IDMSDBL3, and IDMSDBL4 have the ability to call a user exit named DBLUEREX when processing errors are encountered. This exit will be called if an unexpected error status is returned from a call to CA IDMS for all three modules. The exit is also called by IDMSDBL3 if an error is encountered while processing the intermediate file containing records to rebuild the database's chain sets.

The DBLUEREX module must be linked with each IDMSDBLx module from which the user wishes it to be invoked. The modules must be coded so that they are able to run with AMODE=31 and RMODE=ANY so that they will match the modes of the IDMSDBL? modules. The following statements should be used to link DBLUEREX with the desired module(s).

INCLUDE LIB1(DBLUEREX)
INCLUDE LIB2(IDMSDBL?)
ENTRY #DDNHD

where the ? represents 2, 3, or 4 depending on the module to which the exit is being linked.

Upon entry to DBLUEREX, Register 1 will point to a list of three fullwords with the following contents. The last fullword in the list will have its high-order bit turned on to signal the end of the parameter list.