Using the Product in an IMS Environment › IMS Region Types

IMS Region Types

IMS processing can occur in a number of environments. CA Mainframe Application Tuner enables you to resolve performance problems and is capable of monitoring each of the following types of IMS processing.

IMS batch processing

IMS processing might occur in a batch region.

During this type of processing, all IMS activity occurs in one region. A batch program can process all full function IMS databases, but cannot access DEDBs or MSDBs. Batch programs are used when a large number of updates must be done, or when large reports must be created. Batch programs do not require a control region and other programs might not have concurrent access to the databases used by the job.

IMS batch message program

IMS processing might occur in a batch region that is connected to a control region or DBCTL region.

This type of processing is used also when a large number of records are updated or a report is created. This type of processing requires the control region. When you use a control region, recovery is made easier and other programs are allowed to access the databases concurrently.

IMS message processing program

IMS processing might occur in a region called a message processing region or MPR.

The MPR processes transactions that are created in an online environment, which means that a user can be sitting at a terminal entering interactive work and the IMS control region is scheduling work in the MPR. Normally the output message produced by this kind of IMS processing is destined for a terminal user. This type of processing requires a control region to control the terminal I/O and a DBCTL region to control the access to the databases. Other programs can access the databases while messages are being processed.

IMS fast path program

IMS processing might occur in a special region called a Fast Path region.

These regions are usually devoted to processing online transactions that require very fast response times. Programs running in this environment normally access Fast Path databases such as Data EntryDatabases (DEDBs) or Main Storage Databases (MSDBs), but might also access full function IMS databases. They have similar requirements to MPR processing.

CICS transaction access

IMS processing might occur on behalf of a transaction that is executed in a CICS environment.

In this environment, the IMS data is either attached locally or attached by using a DBCTL region. The CICS transaction processing is similar to IMS. You enter a query or update and the IMS connection reads or alters the database. If the database is accessed by using a DBCTL, other programs might access the data concurrently. If the database is locally attached, only CICS shared database processing can occur concurrently.

CICS shared database processing

IMS processing might occur in a CICS environment that uses a batch job. You can run a shared database program only in a local DL/I environment. The batch job runs in its own region, but the CICS region synchronizes the updates to the IMS databases by using "mirror" transactions to process each request of the batch job. Shared database programs can use full function IMS databases.