JMeter Processors and Controllers

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Interleave Controller

This controller lets you increase the scope of your performance testing by modifying sequence in n number of ways so that you get to test the load on the server when applications are hitting request with different sequences. Interleave Controller makes alternative selections with the samplers under it.

In case there are other controllers like Simple Controller kept under this block, interleave controller gives the privilege to select one sampler each from a container for each iteration. To explain it further, consider the below test plan.

So, Jmeter will iterate alternatively between the controllers for each iteration.  Therefore, sequence will be mentioned below

Request1 -> Request3 -> Request 5 – Request2 -> Request4 -> Request6

Please see the below JMeter Results with Number of Threads = 2 and Loop Count = 2.

In above example, Jmeter is Interleaving with next loop/iteration. There are settings in Interleave Controller that can make JMeter send alternate requests with every new thread.

Please see the results below. This is useful in scenarios where you want sequential or concurrent load hitting servers with the different sequence of the request from the same machine.

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Random Controller

It works almost like Interleave controller but does not pick the samplers in order. It just selects the sub controllers and the samplers inside them on a random basis.

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If Controller

If Controller works in a similar way an IF expression is treated in any programming language. The condition is validated first and then the components under this container execute if the condition is TRUE, otherwise, the elements outside the IF Controller will get executed.

Example: Continuing with one of the earlier examples involving Interleave Controller, now one of the two Interleave controller has been kept under the IF Controller and Condition “$(COUNT) < 10 is added as a condition. Variable COUNT is defined in config element “User Defined Variables” and is given a value equal to 11. Configuration is described below

Defining and Assigning a value to COUNT Variable.

Defining condition in If Controller settings. Jmeter will validate this condition and if TRUE, will execute the blocks under this container.

As you can see from below test plan, only Request3, Request4 and Request5 will execute in case IF Condition is evaluated as False.

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While Controllers

This controller executes the components under it till the condition becomes false.

For example, say we have a condition while($(count)<10), it will execute the child elements until the condition is false.  To test this, there should be a counter which gets increment or decrement on each iteration and then condition is evaluated. Config Element “Counter” can be used to serve this purpose.

Configure “Counter” config element to start at 1 and then increment at each iteration. See below for more clarification:

We will touch upon rest of the controllers in our video tutorials.

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Real Time Example

Let’s consider a scenario in which testing team does not know the URLs and parameters of all the request hitting the server under test. Now, to load test the server they need to record the requests and then modulate the load sequentially or concurrently and create scenarios out of them to do the performance testing.

Steps

• Add a template in Jmeter for Recording Controller
• Set the proxy on your browser and choose the same port in HTTP(s) Script Recorder
• Record the requests
• Modify the Test Plan and increase the load
• Group the transactions accordingly
• Try different combinations of request
  
  

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JMeter’secording Template

JMeter also has some predefined template. Select “Template” option from File Menu. After selecting the template to choose “Recording” option in the window which opens and click on Create.

As soon as you select this Recording Template, you would see some components already added in the Test plan.

• HTTP(s) Script Recorder under Work Bench
• HTTP Request Defaults and HTTP Cookie Manager
• Recording Controller Under Thread Group.
  
  

You can either do proxy settings on your browser to talk to JMeter proxy server or use CHROME Extension Blazemeter to record the requests and then export the. jmx file to Jmeter.  There are many others extensions to record the script and then export it to JMeter. BADBOY tool also works well with Jmeter for recording both web and mobile hits.

Click on. jmx option to export the recorded request to Jmeter. Now from Jmeter, open the. jmx file and see the requests and the parameters associated with each request.

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Conclusion

By now, it is assumed that you all must have got yourself very familiar with the basic logic of JMeter, how it simulates load, how to play with different type of Samplers, how to control execution flow with the use of Controller and using variables and functions to run the loops across the iterations. This is certainly not the end of the series of tutorials on JMeter.

There are many video tutorials to follow which will guide testers with more hands on different scenarios in Jmeter and how each JMeter component can be utilized in the best manner.

=> Check the complete list of JMeter video tutorials here

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Source

AlexQin

good job

AlexQin

good job