Overview of BMC AMI Data Packer for IMS

Compressing the data in an IMS database has two advantages. First, physical storage is reduced, and second, performance is improved because less physical data is moved in each database operation. Data Packer provides both of these advantages while improving overall performance and maintaining data integrity.

Data Packer decreases the physical I/Os needed to process data. Programs that process the database sequentially, such as image copy, database unload, and database reload, realize significant improvement from this factor. The BMC Database Utilities products also perform better when working with compressed databases. Because compressed segments consume less space in the database, Data Packer creates more room for growth, and it becomes less likely that the four gigabyte limit will be reached. This extends the life of the databases without your having to make application changes.

Data Packer provides the following features:

• Customized compression techniques
• Utilities for estimating compression
• Space optimization features
• Online registration processes
• Reorganization and exit utilities

Data Packer gives you a choice of compression techniques and provides customized compression. With Data Packer, you can analyze the amount of storage that is saved with each compression technique before deciding on a technique to use to compress your data. You can select features that optimize the free space in your databases and use the ISPF interface to readily specify these features and to customize the compression of your data.

Data Packer supports the following database types:

• IMS full-function databases
• High-availability large databases (HALDBs)
• Data entry databases (DEDBs)

Compression-techniques-and-features summarizes the availability of Data Packer compression methods and features by database type.

This section contains the following topics: