Design – Build – Run: Applied Practices and Principles for Production-Ready Software Development

Chapter 10. Batch

This chapter examines batch and batch processing. Batch processing has its roots in the mainframe era with the earliest batch or job schedulers. Batch jobs run in the background without operator interaction. Batch jobs do not have a user interface; all inputs to a batch job are either through command parameters, scripts, configuration files, or configuration data. Traditionally batch was an overnight activity, with jobs processing millions of records and taking hours to execute — the theory being that there was a very large batch execution window between the end of one business day and the start of another. This is still very true today for some organizations and financial institutions, which enter transactions on the system during the business day and process them at the end of the day. Printing is another batch-related task in which letters, bills, and other documents are printed in the background. Today the batch window is ever decreasing with 24/7 availability requirements.

This chapter is organized into the following sections:

• Batch Processing — Discusses the batch processing required in today's software systems and the different batch processing groups. It looks at the batch window and some techniques for reducing the batch window.

• The Batch Scheduler — Examines the batch scheduler, batch jobs, and schedules. It also looks at the dependencies betweens jobs and groups, as well as at the batch nodes and node groups.

• The Batch Run Date — Highlights the importance ...