IMS Database Reorganization Expert for z/OS details

Reorganizing the IMS database

Using the following tools, you can reorganize the IMS database into a shadow database – essentially a new copy of that database. For IMS™ Database Reorganization Expert for z/OS® to run operations in parallel, the shadow data sets need DASD work space to be the same size as the work space for the input data sets. The original data sets can be deleted automatically when the name-swapping operation between the original and shadow data sets ends.

IMS High Performance Unload

IMS High Performance Unload extracts the data from the input database and passes it to IMS High Performance Load through a data “pipe,” reducing the number of I/Os since the need for an unload file is eliminated.

IMS Index Builder

IMS Index Builder enables secondary index information to be passed from the reload task to the index-building task for processing through another data pipe. IMS Index Builder creates secondary indexes for the reorganized database during the reorganization process.

IMS High Performance Image Copy

With IMS High Performance Image Copy, database blocks can be passed directly from the reload task to an image copy task for processing. Image copy data sets can be created for the reorganized database and the rebuilt indexes during the reorganization process.

IMS High Performance Pointer Checker

IMS High Performance Pointer Checker allows HASH pointer checking during the image copy processing. The IMS Parallel Reorganization Driver (IPR Driver) schedules and controls the tasks of unload, reload, index-building and image copy in a single job step. Since these tasks are handled by the five IBM high-performance tools and intermediate data is passed between subtasks without physical I/Os, reorganization is completed rapidly.