Controller And Its Use In Loadrunner Software You Must Know
By Sam Z // Friday, November 15, 2013
You can control and create the various scenarios of Loadrunner with the help of Controller—a powerful LoadRunner's tool. The events occurring in the course of each testing session is referred to as a scenario. Scenarios are effective in controlling the number of users and their various actions along with the machines that act as platforms for running their emulations. They are used to create load tests sessions that are required for checking the strength and reliability of your servers.
Given below is a list of primary items that need to be defined in your scenarios:
Type of scenario-manual or goal oriented.
Tests to run- the Loadrunner unit tests or scripts required to run.
The machines upon which these tests will be run.
The number of Vusers (virtual users) required to run on every machine.
Scheduling-which is linked to the ways of loading the Vusers.
Measurements that require monitoring during the test runs.
When the Controller is opened for the first time, it will prompt you to put in your selection for the type of scenario-manual or goal-oriented.
Goal Oriented Scenario:
In this type of scenario, you need to define the goals that you desire your test to achieve. After receiving your inputs, LoadRunner automatically constructs a scenario as per the goals set by you. Citing examples, you can set a goal for a particular number of Vusers to use the scenario simultaneously or define a different goal to set the various attributes of your server performance such as Hits per Second, Pages per Minute and/or Transactions per Second.
Manual Scenario:
Here you can select unit tests/scripts and add Vusers in a manual way. You can also use your discretion to distribute them on all available machines.
Controller Technology:
While using the Controller, you can define a specific number of Vusers (apart from GUI Vusers) to create load on a particular server—by submitting their inputs directly onto the server. It is important to understand that Vusers don’t operate client applications and they access the servers by using the API functions of Loadrunner. The API functions are equipped to emulate inputs from actual applications. This takes place because Vusers do not rely on client software. As a result you can use Vusers for testing server performance—much before the development of the client software.
As Vusers do not enjoy a user interface, the volume of system resources allocated and required is minimal. This in turn permits you to run a higher number of Vusers on a specific workstation. The example given below illustrates the role of Vusers in a given scenario.
Suppose your web presence boasts of a database server that is responsible for maintaining information linked with your customers. This information will be obviously accessed by multiple customer service personnel located across the country. The web based server receives all queries, processes them in the right way and returns the responses across the internet to the requisite field personnel. You would like to test the response time of the full system, when many personnel access the server simultaneously. LoadRunner allows you to create a scenario using hundreds of Vusers—with each one accessing your server database at the same time. These Vusers allow you to measure and emulate the performance of Web servers and your database under the load of multiple users.
To emulate Vusers, you need to create a script that defines their actions. A Vuser script contains functions that controls script execution and specifies the various inputs submitted by the Vuser to the server.
You can develop a Vuser script for the example stated above. The created script performs the under mentioned actions:
It logs on to the Web application
Connects directly to the database server
Submits SQL queries
Processes and retrieves the server’s response
Disconnects the application from the web and server.