When a process is serialized, there may be plenty of available capacity, but it cannot be used. For example, if there are four CPU cores providing 240 seconds of CPU power over a 1-minute period (4 _ 1 _ 60), but a single stream process is serialized, it can only hope to consume at most 60 seconds of CPU. If we look at the operating system during the serial process, average CPU utilization will be 25%, while our CPU-intensive batch process crawls along. What is needed is increased parallelism to take advantage of the additional and available resources.

We can mathematically determine batch process segment elapsed time by simply dividing the required resource time by the available parallelism. For example, suppose a CPU-intensive batch process segment consumes 120 seconds of CPU. When run serially, this process takes 120 seconds. After some analysis, it was determined the process could be split into three parallel streams without any Oracle concurrency issues. The anticipated elapsed time becomes 40 seconds. The formula is as follows:

For this example, 120 seconds of CPU is required and three parallel streams are available, so the anticipated elapsed time is 40 seconds. If we looked at the average CPU utilization, it would now be around 75% busy, because only three of the four available CPU cores are being used.