Business transaction services (BTS) introduced a business transaction model to CICS®.
BTS can be used to create a type of program that controls the flow of many separate CICS transactions so that these individual transactions become a single business transaction.
Since a BTS transaction may comprise many separate CICS transactions and may also span a considerable execution time, there are no specific performance recommendations for BTS transactions. There are however, some useful general observations.
To support BTS function, CICS keeps data in new types of data sets the local request queue (DFHLRQ) and BTS repository.
The local request queue data set is used to store pending BTS requests. Each CICS region has its own data set. It is a recoverable VSAM KSDS and should be tuned for best performance like a VSAM KSDS.
You may have one or more BTS repositories. A BTS repository is normally a VSAM KSDS and is used to hold state data for processes, activities, containers, events and timers. A BTS repository is associated with a process through the PROCESSTYPE definition. If the activities of a BTS process are to be dispatched on more than one CICS region, their BTS repositories need to be shared between those regions. The repository can be either of the following:
To support the execution of the BTS processes, CICS runs one or many transactions. A BTS process consists of one or more activities. Each activity executes as a series of CICS transaction executions. If an activity becomes dormant, waiting for an event for example, the activity restarts after that event occurs, and a new CICS transaction is started, even if this is a continuation of the business transaction. You may see many executions of the transaction identifier specified in a process or activity definition in the CICS statistics for a single BTS transaction. The application program executed when an activity is executed is not necessarily the one defined in the transaction definition. In BTS, the Process or Activity definition in application programs can specify a different program to execute.
The number of transactions executed and number and type of file accesses to the BTS repository depend on how you have chosen to use BTS services. Examining CICS statistics reports will give you this information for your applications. You should be aware that containers are stored on the BTS repository. You need to ensure that the repository is large enough to contain all the active BTS data. This is probably best done by scaling it based on a test system.
Monitor data, DFHCBTS, can be used to collect information on activities within processes. For information about this data, see Performance data in group DFHCBTS