Introduction

LoadRunner load tests your application by emulating an environment in which multiple users work concurrently. While the application is under load, LoadRunner accurately measures, monitors, and analyzes a system’s performance and functionality.

Modern system architectures are complex. While they provide an unprecedented degree of power and flexibility, these systems are difficult to test. Whereas single-user testing focuses primarily on functionality and the user interface of a system component, application testing focuses on performance and reliability of an entire system.

For example, a typical application testing scenario might depict 1000 users that log in simultaneously to a system on Monday morning: What is the response time of the system? Does the system crash? To be able to answer these questions and more a complete application performance testing solution must:

• test a system that combines a variety of software applications and hardware platforms
• determine the suitability of a server for any given application
• test the server before the necessary client software has been developed
• emulate an environment where multiple clients interact with a single server application
• test an application under the load of tens, hundreds, or even thousands of potential users

Manual Testing Limitations

Traditional or manual testing methods offer only a partial solution to load testing. For example, you can test an entire system manually by constructing an environment where many users work simultaneously on the system. Each user works at a single machine and submits input to the system. However, this manual testing method has the following drawbacks:

• it is expensive, requiring large amounts of both personnel and machinery
• it is complicated, especially coordinating and synchronizing multiple testers
• it involves a high degree of organization, especially to record and analyze results meaningfully
• the repeatability of the manual tests is limited