Reorg DBD utility—overview

During a database reorganization, IMS does not need to look at expanded data unless the segment data includes a secondary index source field or is involved in a logical relationship. Segment prefix processing is not affected by 

Data Packer

 during a reorganization because 

Data Packer

 compresses data after the key.

The Reorg DBD utility uses this principle to create a temporary reorganization database description (DBD) that bypasses unnecessary expansion and compression. This saves both CPU time and I/O and allows the database reorganization to run much faster.

The Reorg DBD utility can create a DBD that can be used to delete segments with errors. By using a Reorg DBD, compression is not invoked, which bypasses error processing allowing you to delete the segment in error.

You can also use this utility to generate DBDs to be used during reorganizations for DBD modifications. If, for example, you are adding a secondary index, you can leave all segments compressed during the unload except the secondary index source segment.

Note

If you are using the LOADPLUS and UNLOAD PLUS utilities of the BMC MAXM Reorg/EP Express for IMS product, you can also bypass this expansion/compression overhead without using a Reorg DBD. For more information, refer to the documentation for these products.

If you are using the BMC AMI Database Integrity for IMS product, you must have the Label Checking option turned off before using the Reorg DBD utility. For details, see the 'Working with Labels Interactively' section of the BMC AMI Database Integrity for IMS documentation.

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Exits-and-utilities

 

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