Load Testing using JMeter Ultimate Tread Group

Introduction

Load Testing is crucial to determine amount of simultaneous users able to use the web application without any glitch. To satisfy the load requirement JMeter can be used to determine the load web application can sustain. In real world scenario the load of the application does not increase or decrease in a constant manner but it varies at different times. In order to test such a scenario where load is increasing or decreasing with time. We can test web application using Ultimate Thread Group with varying users for certain time slot the load remains constant then again increase or decrease based on our configuration. Ultimate thread group plugin in Jmeter. 

Prerequisite

JMeter is installed with plugin Ultimate Thread Group.

How to Add Ultimate Thread Group

Right Click Test Plan -> Add -> Threads (Users) -> Ultimate Thread Group

Configure Ultimate Thread Group

This is most important step, to configure the number of virtual users with which you will be testing the web application.

1. Action to be taken after sampler error - By default Continue is selected
• Continue - Select this option if you wish the test to continue on sampler error.
• Start Next Thread Loop - Select this option if you wish the test to start the next thread group on sampler error.
• Stop Thread -  Select this option if you wish to stop the current thread on sampler error and continue remaining threads.
• Stop Test - Select this option if you wish to stop the test on sampler error.
• Stop Test Now - Select this option if you wish to abruptly stop the test on sampler error.
2. Threads Schedule - Click Add Row and Configure below parameters
1. Start Threads Count - Number of virtual users for particular time slot.
2. Initial Delay, sec - Initial delay in starting interaction with server.
3. Start Up Time, sec - For a particular time slot, the amount of time taken for starting ramp up of all users of particular time slot.
4. Hold Load For, sec - The amount of time in seconds, the virtual users will remain constant for a particular time slot. 
5. Shut Down Time, sec - The amount of time in seconds, the virtual users will ramp down and stop for particular time slot.

Once you configure the above two steps, you will be able to visualise the total load on the server. The below figure depicts the load of 300 virtual users. you may configure the total virtual users according to your requirements.

Next Step is to add a Sampler to the Ultimate Thread Group that we just configured. For example we will add HTTP sampler and configure it. Also, to visualise the active users over time for our defined test, add 'Active Users Over Time' listener.

Samplers in JMeter is nothing but program which sends different type of requests to a server for example HTTP request that we just added.

Listeners in JMeter is program to view or analyze the result of performance tests in tabular or graphical form for example 'Active Users Over Time' listener.

Conclusion

Ultimate Thread Group, when configured for varying users or threads for different time slot helps us to load test the web application with projected users in real environment.