Many Oracle systems contain a mix of online and batch processing, or perhaps more online-focused during the day and batch-focused during the night. Obviously, improving batch processing performance is just as important as improving online processing.

There is a significant difference or shift in focus when working on batch processes. Our concern shifts from response time per unit of work to total response time. In other words, we are more concerned about how long it takes to process 500MB of IO or 5,000 seconds of CPU compared to the response time of a single physical IO. Another way of looking at this is our unit of work becomes the entire batch process or a step in the batch process.

While the response-time curve can be used when working with batch processes, because of the longer and singular process time focus, it is not nearly as useful. The response-time curve shines when it relates time to small units of work, like a logical IO or the execution of a SQL statement. Because our focus has shifted from small units of work to an entire process or process segment, our method of reflecting the situation must also change. Instead of using a response-time curve, the situation can be conveyed numerically in a table format (see Table 9-5) or by using a simple timeline.