Running sampler of jmeter in isolation - jmeter

Suppose my threads are 30 and iteration count is 1 and I have samplers such as:
sampler1
sampler2
sampler3
....
sampler10
Whenever I run the test plan with corresponding ramp up period some of my samplers are being executed concurrently I meant user 1 is executing sampler1 and also user 20 is executing same sampler which is absolutely fine but I want sampler3 to be executed in isolation i.e. when that sampler is being executed by someone no other user should try to access it.
Is there any way?
I am using Jmeter.
Thanks in advance

As per Using the HTTP Cookie Manager guide you can put your Sampler 3 under Once Only Controller
From documentation
The Once Only Logic Controller tells JMeter to process the controller(s) inside it only once per Thread, and pass over any requests under it during further iterations through the test plan.

Related

How to chain HTTP request requests in Jmeter Simple Controller?

I have multiple Simple Controllers under Thread group. All controllers have 1 HTTP request. Only one controller have 3 requests. How can I chain 3 requests in one simple controller to run sequentially.
Test Plan
The screenshot above is my test plan. In v4/bootstrap call I have 3 HTTP requests. Result of these 3 requests is token which I extract from get_v4/restart and then this token used for all other requests. For correct token generation 3 requests from v4/bootstrap call should run sequently. On summary report shown that amount of run 3 requests is different.
Each JMeter thread (virtual user) executes Samplers upside down. The same applies to Simple Controllers.
So you don't need to do literally anything, each thread will execute samplers sequentially as they appear in the Test Plan.
If you have more than 1 virtual user in the Thread Group you might be confused by the "wrong" order of sample results:
However each user is still executing samplers upside down, you can check it by adding __threadNum() function to show the current virtual user's number and __groovy() function calling vars.getIteration() method
You will see that each user executes samplers sequentially and starts over when the last sampler ends and there are iterations still:

How to run both request/sampler successfully

I am trying to run http samplers sequentially for multiple requests. Where the output of 1 API response is the input of next API request. My concern is when I run with 5 users (for. e.g), then at given point of time it first executes 1st API with 5 users then second API with 5 users, in this process the API where input is required gets lost. Please help me on this.Actually I have used transaction controller also but here not sequentially api run,so getting file not found exception bcause of first api output response parameter is not passed to second api as a input parameter
I need a solution, where all the samplers are first executed for first user, then for second thread all the samplers are executed and so on.
Each JMeter Thread (virtual user) executes Samplers upside down, if you have 2 samplers each user will always run 1st sampler then it will run 2nd sampler.
You can use __threadNum() function and ${__jm__Thread Group__idx} pre-defined variable in order to verify that the execution order is sequential.
If you want all the users to execute first sampler then all users to execute the second sampler - go for Synchronizing Timer
If you want to get to the reason of the failure try saving the responses using i.e. Simple Data Writer as it might be the case your "first" API fails silently and hence your correlation doesn't extract the value.

What jmeter configuration I should use when running load test of 25 threads

I need to run a load test of 25 threads, what will be the most efficient configuration to use? (ramp-up period....). I ran the load test with the below configuration and some of the threads failed but pass if I just ran the script individually.
Your configuration will mean that:
JMeter start with 1 thread and add another thread each 4 seconds
Once started each thread will begin to execute Samplers upside down (or according to the logic controllers)
When the thread executes the last sampler it will be shut down
When the last thread executes the last sampler the test ends
Depending on the number of samplers and application response time you may or may not achieve 25 users concurrency, you might want to check the actual number of concurrent users using Active Threads Over Time listener
If you want to make sure to have 25 online users set "Loop Count" to Infinite and "Specify Thread Lifetime" duration to be more than your ramp-up period. See JMeter Test Results: Why the Actual Users Number is Lower than Expected article for more details.
With regards to the failures - we cannot state anything meaningful without seeing request and response details, make sure to save them using i.e. View Results Tree listener and inspect response body for the failed requests

How i can be sure that JMeter is not using the same sample more than one time at same time?

I'm using JMeter to test my applications, and I desire to use the same sample N times.
For example, lets say I have 100 different samples how I'll use to test my Login, and want to use these samples 10 times.
I'm using 100 threads, and 10 loops for that.
How I can be sure that the second loop using a sample will start just after that the first loop of that sample has finished (and not have the same sample running simultanious)?
I'm having some troubles to understand how JMeter lead to this scenario.
JMeter acts as follows:
Each thread (virtual users) executes Samplers upside down (or according to the Logic Controllers)
When there are no more Samplers to execute:
-if there is > 1 loop in the Thread Group - the thread starts executing Samplers once again
if there are no more loops to iterate - the thread is being shut down
You can track which thread is executing which sampler by adding __threadNum() function to the sampler name. The Thread Group iteration can be tracked by adding the special JMeter Variable ${__jm__Thread Group__idx}
If you don't want user 1 and user 2 to execute sampler1 at the same time - put this sampler under the Critical Section Controller, but in this case you will not have any concurrency.

How to enforce run Once Only Controller in Jmeter

I'm a newcomer to Jmeter and want to be able to run some setup requests once only, in which some variables are setup, before I then run a set of further requests for as many users as I set in the Number of Users Thread Group. These users are passed the variables created in the Once Only Controller.
I've inherited a script as follows, using a Once Only Controller:
If I set the Number of Threads as 10 to ramp up to 10 in one second and run for one minute, I expect the number of Samples (requests) made in the Once Only Controller to show as 1. I only want these requests to run once then subsequent requests to use the setup data.
Why then, when I run, do I see the samples as 10 in the requests that are set in the Once Only Controller:
Bear in mind there may be some fundamental misunderstandings given my I'm a newcomer to Jmeter.
I found the setUp Thread Group Controller which seems to be what I need. However, this does not seem to pass variables extracted using the JSON extractor into the next Thread Group 'Load Test'
Thanks
Use Once Only Controller for running specific samplers for every thread
The Once Only Logic Controller tells JMeter to process the controller(s) inside it only once per Thread
You can add samplers to setUp Thread Group so it'll be executed once before test
execute before the test proceeds to the executing of regular Thread Groups.
Note keep its default (especially Number of Threads = 1)
As per Once Only Controller documentation:
The Once Only Logic Controller tells JMeter to process the controller(s) inside it only once per Thread, and pass over any requests under it during further iterations through the test plan.
So each your Thread will execute Once Only Controller's children only once, no matter how many loops your thread group will have.
As you have 10 threads each of 10 threads will execute the requests once.
If you want to execute the request by only one thread, no matter how many requests are in the Thread Group - I would recommend going for If Controller instead
Substitute Once Only Controller with an If Controller
Use the following condition:
${__groovy(ctx.getThreadNum() == 0 && vars.getIteration() == 1,)}

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