Load testing with LoadRunner Professional

This topic introduces load testing and the LoadRunner Professional load testing process.

What testing do you need for your systems?

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, load testing focuses on performance and reliability of an entire system.

For example, a typical load 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 do the following:

  • 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

The LoadRunner Professional suite allows you to create load tests, which emulate the real life behavior of your application.

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The LoadRunner Professional solution

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.

LoadRunner Professional addresses the drawbacks of manual performance testing:

  • LoadRunner Professional reduces personnel requirements by replacing human users with virtual users or Vusers. These Vusers emulate the behavior of real users operating real applications.

  • Because numerous Vusers can run on a single computer, LoadRunner Professional reduces the amount of hardware required for testing.

  • Controller allows you to control all the Vusers from a single point of control.

  • LoadRunner Professional monitors the application performance online, enabling you to fine-tune your system during test execution.

  • LoadRunner Professional automatically records the performance of the application during a test. You can choose from a wide variety of graphs and reports to view the performance data.

  • LoadRunner Professional checks where performance delays occur: network or client delays, CPU performance, I/O delays, database locking, or other issues at the database server. LoadRunner Professional monitors the network and server resources to help you improve performance.

  • Because LoadRunner Professional tests are fully automated, you can repeat them as often as you need.

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The testing process

The following steps provides a general overview of the LoadRunner Professional testing process.

  1. Plan the test

    Successful load testing requires that you develop a thorough test plan. A clearly defined test plan ensures that the LoadRunner Professional scenarios that you develop can accomplish your load testing objectives. For more information, see Plan load test scenarios.

  2. Create the Vuser scripts

    Vusers emulate human users interacting with your web-based application. A Vuser script contains the actions that each Vuser performs during scenario execution.

    In each Vuser script, you determine the tasks that are:

    • Performed by each Vuser

    • Performed simultaneously by multiple Vusers

    • Measured as transactions

    For more information on creating Vuser scripts, see the Virtual User Generator Help Center (select the relevant version).

  3. Design the scenario

    A scenario describes the events that occur during a testing session. A scenario includes a list of machines on which Vusers run, a list of scripts that the Vusers run, and a specified number of Vusers or Vuser groups that run during the scenario. When designing the scenario, you set the scenario configuration and scheduling which determines how all the load generators and Vusers behave while the scenario runs.

    You design scenarios using Controller. For information about LoadRunner Professional scenarios, see Design scenarios.

  4. Run the scenario

    You emulate user load on the server by instructing multiple Vusers to perform tasks simultaneously. While the scenario runs, LoadRunner Professional measures and records the transactions that you defined in each Vuser script. You can set the level of load by increasing and decreasing the number of Vusers that perform tasks at the same time and you can also monitor your system's performance online. For more information, see Run scenarios in Controller.

  5. Monitor the scenario

    You configure the LoadRunner Professional monitoring components to identify bottlenecks on the system and determine which element is causing performance degradation, for example, file locking, resource contention, and network overload. Use LoadRunner Professional in conjunction with the new network and machine monitoring tools to create load and measure performance at different points in the system. For more information on monitoring, see Monitor load test scenarios.

  6. Analyze test results

    During scenario execution, LoadRunner Professional records the performance of the application under different loads. You use LoadRunner's graphs and reports to analyze the application's performance. For more information about reports and graphs, see Introducing Analysis.

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