Creating Rendezvous Point in JMeter

Rendezvous point in load testing is a point where an expected number of users wait till all of them are emulated, and then all virtual users send request at one time. This point is created to check the behavior of application where it might get a huge number of requests at a particular time. Its very important to test a Peak Load Scenario when approaching towards load testing a web application.

Jmeter, being the best alternative to commercial Load Testing Tools in the Open Source Arena, here is a way to find this "Rendezvous" point in Jmeter.

The tree elements for our sample test plan would be like

Test Plan
Thread Group - Lets give Number of Threads to be '200'
HTTP Request - Lets hit http://www.ourgoalplan.com with 200 users 

Synchronizing Timer - Add this timer and enter '50' as the number of virtual users we want to send request to the server simultaneously
View Result Tree - Use this listener to monitor the performance of the application
Aggregate Report - Use this listener to see the overall performance

Now, as we wanted our application to be hit by 200 virtual users, with the pre condition that 50 users should hit the site in four sets i.e. 50, 50, 50 and 50 which makes 200. Press ctrl + R to run the script after saving.

We would see the users getting emulated and sending request in the same pattern as we wanted by creating a Rendezvous Point.

PS : Number of threads in the Thread Group should always be greater than the 'Number of Simultanous Users to Group By' to make sure that Jmeter doesn't throw any unhandled exception. Its always good to be on the safer side when going forward with Open Source Tools.

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