Overview of the Reload function

The following figure shows the system flow for the Reload function.

When you execute the RELOAD command, the first program to be executed is the BMC version of the batch region controller (DFSRRC00), which loads and transfers control to the Reload function.

When the Reload function receives control, it determines the values to use for the user-controlled options as explained in How-the-utilities-build-options.

The Reload function builds miscellaneous control blocks, opens data sets, and begins reloading the database. It retrieves input segments from the HD Unload data set in hierarchical order. If the key fields are not compressed, the Reload function checks the sequence of these segments. It uses standard OS access methods to build the database data sets and accumulates various statistics as it builds the database.

When the reload process completes, the Reload function closes the database data sets and generates various reports, which can be stored in the PDX. You can view these reports, and previous reports for the same database, any time through the ISPF interface.

Secondary index records are written to the DFSURWF1 data set.

If the database contains logical relationships, the Reload function builds the work file 1 records needed by the IMS Prefix Resolution utility or the BMC Prefix Resolution/Update function.

If you specify the PRPURWF1 DD statement, the Reload function separates the logical relationship records from secondary index records and writes the logical relationship work file records to the PRPURWF1 data set. The PRPURWF1 data set can be processed only by the Prefix Resolution/Update function. Subsequent processing of logical relationship records and secondary index records can be performed simultaneously, reducing elapsed time.

The Reload function works with DBRC in a similar manner to the IMS HD Reorganization Reload utility. The same exclusive authorization is done, and a NOTIFY.REORG is issued. Additionally, the utility turns on the prohibit authorization action at the beginning of the Reload function and turns it off at the termination of the Reload. The prohibit authorization action prevents an incompletely loaded database from being placed online.