IMS Database Repair Facility overview

IMS Database Repair Facility for IMS Solution Packs (also referred to as IMS Database Repair Facility) is a powerful tool to repair VSAM and OSAM organized IMS databases that contain pointer or data errors.

It can be run both interactively and in batch mode for VSAM and OSAM data sets. In batch mode for VSAM data sets, it supports both IMS data sets and non-IMS data sets. The interactive capabilities of IMS Database Repair Facility helps you make the repair in a short time, which means that the affected database need be taken offline only for a brief period. In this way, IMS Database Repair Facility enhances not only the integrity but also the availability of IMS databases.

Pointer and data corruption occur during power failure situations. They also might result from severe application errors or other mishaps to data sets that reside on DASD devices, such as I/O errors. Pointer errors are found by examining the output of Pointer Checker jobs; data errors are generally reported by end users.

When you determine the bad pointer or data, use the interactive IMS Database Repair Facility to navigate around the database for additional validation purposes. Do this step to verify that other pointers or data were not corrupted.

Using IMS Database Repair Facility, you can change the bad pointers and data to the values you think they should have. Despite the fact that you use utmost caution, errors sometimes occur.

To address this problem, IMS Database Repair Facility, when run interactively, has an Undo feature that reverses pointer and data changes. When IMS Database Repair Facility is used to update a database, the tool keeps a file of before and after pointer and data images. This file is kept until the next time IMS Database Repair Facility is started and used to create a change against the same database.

It is strongly recommended that you use the Pointer Checker utility immediately after you make updates to your database. Then, if an error is detected, you can use the interactive IMS Database Repair Facility's Undo function to back out the change.

This information is also true for the batch operation of IMS Database Repair Facility. However, no Undo facility is available. Instead, you can reverse changes made in error by using information that is provided in the Control Statements and Messages report.

IMS Database Repair Facility also provides the ILK Repair utility. Use the ILK Repair utility together with the HD Pointer Checker utility (of IMS HP Pointer Checker) to repair HALDB databases that have corrupted HALDB partition reorganization numbers, duplicate indirect list keys (ILKs), or potentially duplicate ILKs. For information about corrupted HALDB partition reorganization numbers, duplicate ILKs, or potentially duplicate ILKs, see the IMS High Performance Pointer Checker User's Guide.