The goal of performance testing is to ensure that the non-functional performance requirements of the product are met. This generally translates to the following:
- Latency: The application should respond quickly, as described in the latency SLAs for various operations.
- Scalability: The application should handle the maximum prescribed user, and yet maintain the latency characteristics described previously.
- Stability: The application should be stable under varying load and load ramps.
There are various types of tests that ensures the preceding goals:
- Load/Stress tests: These check the application's ability to perform under various levels of loads (requests per second). The objective is to measure latency and the stability of the system under various conditions of load or stress.
- Volume-testing: Under Volume-testing, a large amount of data is populated in a database and the overall software system's behavior is monitored. The objective is to check the software application's performance under varying database volumes. These tests bring out issues with database modeling, such as an index not created on often-queried columns.
- Scalability Tests: The objective of scalability testing is to determine the software application's effectiveness in scaling-up to support an increase in the user load. It helps to plan addition to your software system. The tests aim to identify scaling bottlenecks and typically measure time to handle a request as a function of load, as depicted in the following diagram:
- Endurance testing: This test is performed to ensure that the software can handle the expected load over an extended period of time.
- Spike testing: It tests the software's behavior for sudden large spikes in the load. Generally, steep ramps in load can bring out issues that are different from endurance tests (constant load).
The following diagram illustrates the various tests we just discussed:
