Conversion to DEDB

When an HDAM, HIDAM, or HISAM database is converted to an IMS Fast Path data entry database (DEDB), certain conditions must be satisfied.

These conditions are:

• The segment of the full-function database must be variable-length.
• DBD, PSB, and ACB must be generated before running FABRRELD to reload DEDB.
• VSAM data sets for the reloaded DEDB areas must be defined by Access Method Services (IDCAMS), and initialized by the IMS DEDB Initialization utility (DBFUMIN0).
• DB Segment Restructure reload program FABRRELD must run under IMS BMP region.

Because FABRRELD issues a SYNC call internally to reuse NBA/OBA buffers, the performance of the reload processing depends on how frequently the SYNC call is issued. The more number of NBA buffers are specified, the less number of SYNC calls are issued, that is, performance is improved. But note that this improved performance might offset the performance of other applications concurrently running under other dependent regions.

Fast Path HSSP can be applied to elicit good performance for reloading DEDB. This can be achieved by specifying PROCOPT=H in a PCB statement of this reload program PSB.