Overview
Reorganize IMS databases while they remain online
IBM® IMS™ Online Reorganization Facility for z/OS® reorganizes many types of IMS databases while they remain accessible to applications. Using this product, the IMS Database Administrator (DBA) can now reorganize an IMS database while allowing full IMS application access to the database.
Features
Reorganize an IMS database
IMS Online Reorganization Facility for z/OS handles all of the tasks required to reorganize an IMS database including: unloading and reloading the data, resolving database prefixes, rebuilding secondary indexing, validating database pointers and image copying the reorganized database.
Get all the necessary reorganization procedures in one simple step – eliminating the need for operator intervention during and after reorganization finishes.
Decrease database downtime from hours to seconds – improving database availability for 24x7x365 applications.
Reorganize HDAM, HIDAM, HISAM, SHISAM, PHDAM, and PHIDAM database types.
Protect sensitive data with IBM Z® pervasive encryption and access controls with no code changes required.
Learn more about the IMS online reorganization process
The verification phase is the first phase of the online reorganization process. IMS Online Reorganization Facility for z/OS uses this phase to validate that the IMS database can be reorganized. The tool checks the IMS release and component levels, the DBRC registration and database DBD definitions, the tool control statements, and the shadow and temporary data sets are allocated correctly. The reorganization continues if this verification step completes successfully.
The IMS databases are briefly paused to allow the database buffers to be flushed to the IMS database data sets. This ensures that the latest updates are captured in the original IMS database data sets. Then the original IMS database data sets are copied to the shadow IMS database data sets. When this copy is completed, a second brief pause is performed to capture any updates that were made to the original IMS database data sets. These updates are also applied to the shadow data sets.
Once the shadow IMS database data sets are created, they are unloaded using the unload tool and reloaded using the load tool. If there are secondary indexes, they are also rebuilt. Internal logical relationships are resolved and updated using the prefix resolution tool. The reorganized IMS shadow databases are image copied with the image copy tool and can be pointer checked with the pointer checker tool.
When the reorganization of the shadow data sets has completed, the original IMS database data sets are swapped with the reorganized shadow IMS database data sets. IMS DBRC is notified with the REORG database status. If the IMS DBD database definitions change, the IMS Online Reorganization Facility performs an ACBGEN. Finally, the IMS database is restarted internally by the tool with the /START command and the takeover phase is completed.
In the completion step, the final reports are created and the shadow IMS database data sets are deleted.
Resources
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