DATABASE SYSTEM FOR PERMITTING CONCURRENT INDEXING AND RELOADING OF DATA BY EARLY SIMULATING THE RELOAD PROCESS TO DETERMINE FINAL LOCATIONS OF THE DATA

The reorganization method of DB2 data files explores parallel processing, and asynchronous I/O to a great extent. It includes means to estimate an optimum configuration of system resources, such as storage devices (DASD devices), memory, and CPUs, etc, during reorganizations. The method mainly consists of four components, (1) concurrent indexing, (2) concurrent unloading of data file partitions, (3) efficient reloading of DB2 data pages and DB2 space maps, and (4) means to reduce access constraints to the DB2 recovery table.