Performance Testing covers a set of functional estimations where a product, material, system, or people are not determined by detailed specifications.
Performance Testing has dealings with different test types:
Tests check in what way the system acquits if capacity is transcended. For many systems, there is a standard maximum capacity and a short-term peak, which transcends that capacity. It may happen so that both may need to be handled, or the peak must not induce any harmful influences.
These tests deal with elapsed times. This means that system functions have to be completed within a fixed time. An on-line transaction may be required to complete within 3 seconds; an overnight batch update or a full database backup may be required to complete within a few hours.
Such tests check if a system will run for a clarified period without some weighty, unforeseen trouble happening. It may happen so that a system may operate without problems for some hours but after this becomes slower and slower. This is often due to such reasons as memory leakage or exorbitant disk fragmentation. Endurance testing always tests common system operation, but it may comprise backup and similar procedures deemed necessary over the period of the test.
These tests examine if system functions can be selectively shut down in order overload situation occurs.
Capacity and volume tests
Such tests address maximum rates of processing, data sizing, and hardware configurations. For instance: the highest possible quantity of on-line transactions per second, the highest possible quantity of records open at the same time, the highest possible quantity of workstations that a server has the opportunity to support.