Sending multiple http requests in JMeter, then pausing for some amount of time for firing executions again

Question

I want to send 70000 http requests in JMeter, but I want to do it such that I send 50 requests in one go, then pause for around 6 mins, then send the next 50 and so on until I hit a total of 70000 requests

So far, I have tried a couple different configurations to try this, for eg.

 - Thread group (with number of threads = 1, Ramp-up period = 1, Loop Count = 1400)
     - Loop Controller (Loop count = 50)
         - HTTP Request
         - HTTP Header Manager
         - Constant Timer (Thread Delay (in milliseconds) = 600000)

But this doesn't seem to work. This just seems to fire one request every 1 min (or 600000 milliseconds).

I have also tried

 - Thread group (with number of threads = 1, Ramp-up period = 1, Loop Count = 1400)
     - Loop Controller (Loop count = 50)
         - HTTP Request
         - HTTP Header Manager
     - Constant Timer (Thread Delay (in milliseconds) = 600000)

But it gives me the same result.

Answer 1

JMeter's elements are all about scopes and execution hierarchy. In order to achieve your goal, you can place your timer in 2 ways

1. Use "Flow Action Control" Sampler after your HTTP request or in the scope of your Loop Controller or under the scope of your Thread Group (right click on thread group and select "Add Think Times to Children"
2. Place the timer inside the HTTP Request before which you want the Timer to be executed

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Sample Screenshots

Flow Action Sampler

Timer inside a sampler

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Why you are facing an issue

Basically below is the hierarchy in which JMeter executes your elements

1. Configuration Elements
2. Pre-Processors
3. Timers
4. Samplers
5. Post-Processors
6. Assertions
7. Listeners

Source: https://jmeter.apache.org/usermanual/test_plan.html#executionorder

Since timers have a higher execution priority than samplers, they are bound to get executed before a sampler gets executed. In your particular case, you have placed your timer in the scope of both Loop Controller & Thread Group and hence it is getting executed before each element.

Note that timers are processed before each sampler in the scope in which they are found; if there are several timers in the same scope, all the timers will be processed before each sampler. Timers are only processed in conjunction with a sampler. A timer which is not in the same scope as a sampler will not be processed at all. To apply a timer to a single sampler, add the timer as a child element of the sampler. The timer will be applied before the sampler is executed. To apply a timer after a sampler, either add it to the next sampler, or add it as the child of a Flow Control Action Sampler.

Source: https://jmeter.apache.org/usermanual/component_reference.html#timers

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How the suggested solution works from Timer perspective

Since I am placing the Timer inside a sampler, it gets invoked only before that particular sampler executes. Hence we avoid the timer being applied to every other element

Also, Flow Action Sampler is a sampler itself and hence it gets executed only in the sequential manner and hence when you place it after your respective HTTP request, it will execute only at that instance and hence it will act as expected

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How to be used in your Test Plan

With Loop Controller

For my example I am taking a scenario where I simulate 50 requests, wait for 10 seconds and trigger the next bunch of 50 until 500 requests are reached

Added the Flow Action Sampler inside my loop controller

Defined 50 Threads for my sample test

Loop count in Loop controller is 10

Once I trigger the test, during the first second, all my 50 users have ramped up and triggered 50 requests and are now waiting for 10 second duration. Notice the number of samples, thread count and time

During the 7th iteration, 350 requests have been completed and they are about to reach 70th second

At the end of the test, I have 500 requests. Expectation from my test scenario is that post burst of 50 requests, wait for 10 seconds and continue this pattern for 10 iterations. Hence at the end of the test (~100 seconds later), I will have 500 samples completed.

Without Loop Controller

Follow similar test plan as defined with loop controller, only difference being, non-existence of the loop controller and loop count in Thread Group will be defined as 10

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In either case, Flow Action Sampler has 10 seconds as Pause time

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Hope this helps!