Reorganization utilities

You can reorganize your database by using IMS utilities. This topic introduces you to these utilities and explains how they work together.

For HALDB, both the Database Prereorganization utility and the HALDB Partition Data Set Initialization utility (DFSUPNT0) initialize partitions.

If you are migrating an HDAM or HIDAM database to HALDB, the Prereorganization utility allows some reuse of your existing JCL by disabling full-function database utilities, such as Scan, Prefix Resolution and Prefix Update, in the DFSURCDS data set. After the database is migrated, you can use the HALDB Partition Data Set Initialization utility, which has additional functions such as unconditional specific partition initialization.

The utilities cannot be used to reorganize HSAM, SHSAM, or GSAM databases. To reorganize these databases, you must write a program to read the old database and then create a new database.

You are not required to use these reorganization utilities to reorganize your database. You can write your own programs to unload and reload data. You need to write your own programs only if you are making structural changes to your database that cannot be done using these utilities.

Several of the reorganization utilities can be used when initially loading a database. They are not used to load the database but to collect and sort the pointer information needed in a segment's prefix. Therefore, as you read through the utilities you will find some described as used for initial load or reorganization.

The reorganization utilities can be classified into three groups, based on the type of reorganization you plan to do:

• Partial reorganization
• Reorganization using UCF
• Reorganization without UCF