Communications performance considerations for batch jobs

Each piece of work run on the iSeries™ system is called a job. Each job is a single, identifiable sequence of processing actions that represents a single use of the system. The basic types of jobs that are performed are interactive jobs, batch jobs, spooling jobs, autostart jobs, and prestart jobs.

Batch jobs are predefined groups of processing actions that are submitted to the system to be performed with little or no interaction between the user and the system. Batch jobs can be tuned for optimized performance.

To optimize batch jobs for communications, consider the following:

• Break the application into pieces and having multiple batch threads (jobs) operate concurrently.
• Reduce the number of open and close operations, input and output operations.
• If you have a considerable amount of main storage available, consider using the Set Object Access (SETOBJACC) command. This command preloads the complete database file, database index, or program into the assigned main storage pool if sufficient storage is available. The objective is to improve performance by eliminating disk-read/write operations.
• Try to limit the number of communications input and output operations by doing fewer (and perhaps larger) application sends and receives when communications lines are used.
• Block the data in the application. Try to place the application on the same system as the frequently accessed data.

For more information about batch job performance, see the Communications Management book.