LoadRunner – Basic Terminologies

LoadRunner beginner must have the knowledge of the basic terminologies. These basic terms will help you to grab the core knowledge of LoadRunner as well as performance testing. You have to learn the given definition because you will use them throughout your life. Learning of LoadRunner without understanding the basic term is slightly difficult. So, let’s start to know the basics:

  • SLA: Service Level Agreement is a mutual agreement between the client and tester on Performance Metrics. This can also be termed as “Performance Requirement”.
    Example: The application X must handle 100 users load with 2 TPS for an hour.
  • Performance Metrics: These are the units of measurement for client, server and network statistics.
    Example: Transaction per second, Response Time, Throughput, etc.
  • Transaction: A transaction is a set of end-user actions that represent the real user activities on the application.
    Example: Login, Click_on_Link, Click_Submit_button, Logout, etc.
  • Business Process: A sequence of steps that represent a use case or a business function. It includes one or more transactions.
    Example: Product Order, Search Item etc.
  • Scenario: It is a collection of business processes based on performance requirements. A scenario is a window where you can define no. of users, test duration, Vuser running pattern, etc. along with business processes. Scenario creation is also called as Workload Modelling.
  • Virtual Users or Vusers: Vusers emulate real-world users. It is equal to the expected load on the server.
  • Protocol: The method of communication between a client and the server. The selection of protocol depends on the language/technology of an application.
    Example: Web HTTP/HTML, Ajax TruClient, etc.
  • Load Generator: These are the machines used to generate virtual users.
  • Controller: It organizes, drives, manages and monitors the performance test. The Controller communicates with Load Generators during the test via Agent.
  • Iteration: Repetition of transaction flow specified in the Vuser script.
  • Pacing: Delay between two iterations
  • Think Time: Delay between two transactions
  • vuser_init(): A section of the script which contains initialization part like user-defined functions, user-defined variables, Login etc. It runs only once during the test.
  • Action(): This section contains the business process and runs in an iterative manner. The action part has real-user activities which could be separated by transactions. It may or may not contain Login and Logout transaction depends on how script logic is created?
  • vuser_end(): The exit phase of the script. It also runs only once like vuser_init(). It may have application logoff step.
  • Run Logic: Run Logic defines the number of times all actions will be executed, except vuser_init and vuser_end.
  • Correlation: This is a method to handle the dynamic values generated by the server. LoadRunner has auto and manual correlation options. In autocorrelation, LoadRunner scans the recorded script and identify the dynamic value. In case LoadRunner unable to do so then we need to find out the dynamic value manually using recording and replay logs.
  • Parameterization: It is used to pass different values into the defined variables during the performance test.
    Example: A scenario has 5 Vusers with UserID AA, BB, CC, DD and EE. To pass these values a parameter named _userID is defined which will pass the respective values to the individual users.
  • Rendezvous points: The point where Vusers wait for all other Vusers to arrive and then hit the next transaction simultaneously. It is used to generate full traffic on any specific functionality.

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