I was asked to work out the number of cost calculation per insurance policy needed as the workload for my next performane test. The database luckily held the start time and end time of calculation held for each insurance policy. Great you think just count the number of calculations per hour manipulate in excel and lots of graph to show management before the performance test.
First wait! it is possible that a users can request many cost calculations on a policy but only the results of the last calculation are recorded in the database. So the results in the database don’t tell the true story.
So with that in mind a quick tour of the users suggest that on average they may re-cost the policy 4 times before a figure is acceptable with them and the customer. Luckily we could then take this into account in the test workload and allows us to correctly size the system from the performance test results.