Oracle performance analysis that is fundamentally based on response-time analysis has the inherent advantage of naturally being expanded into anticipating change. To do this, we need to take the components of response time another level deeper, reduce some of the abstraction I have been using in this book, and examine the relationship between response-time components specifically used in an Oracle environment.

When rivers flow into the ocean, people enter an elevator, and transactions enter an Oracle system, over an interval of time, they arrive at an average rate. It could be that just before Friday's time card entry deadline between 4:30 p.m. and 5:00 p.m, 9,000 transactions occurred.

The average arrival rate is expressed in units of work and units of time. In the prior time card example, the arrival rate is likely to be expressed in terms of transactions and minutes. The math involved is very straightforward: divide the total number of transactions that arrived by the time interval. For the example, it would be 9,000 transactions divided by 30 minutes, which is 300 trx/min.