Empty database initialization using the RELOAD command

Because IMS does not allow the creation of a database online, the database must be created offline. Creating an empty database offline involves inserting one root segment and deleting it. This process initializes the database so it can be used online.

You can execute the RELOAD command to perform this initialization function with a JCL statement modification. Specify DFSUINPT DD DUMMY to create a usable empty database. A load PSB is not necessary.

You can initialize an empty database for the following database organizations and access methods:

• If the database is an HDAM or PHDAM database and you specify FMTRAA(YES), the entire RAA is formatted. If you specify FMTRAA(NO), only the first track is formatted. Formatting improves online performance when inserting segments into the database. For more information, see FMTRAA.
• If the database is a HIDAM or PHIDAM database, it contains a root segment with a key of all X'FF's.
• If the database is a HISAM or SHISAM VSAM database, the KSDS is empty, but the high-used RBA is non-zero and the entry-sequenced data set (ESDS) contains a valid record 0.
• If the database is a SHISAM database, the KSDS is empty and the high-used RBA is non-zero.