Hardware and performance

Hello,

At first, please execute your JMeter simulation at command line interface.
If you use GUI mode when you execute the simulation, the JMeter will overwrite test plan file.

Second, this test plan cannot simulate the behavior of more than 1000 students.
If you want simulate the behavior of more than 1000 students, you should modify "testuser.csv" and add more students to your Moodle site.

Next, this test plan does not support simulation iterations.
So, you cannot repeat the simulation while one execution of the JMeter command.

Moreover, many login errors occurred in your simulation.
In that case, JMeter cannot get "sesskey" value for each student.
If all students login safely, each student have his/her own sesskey value, and, URLs of numbers 73 and 74 are different for all students.
Please confirm settings of your Moodle web server (maximum number of connections, and maximum number of open files, etc.).

If you use this test plan correctly and your web server can open enough number of connection ports, and still get login errors, your web server may not be performing well.
In general, HTTP service software (apache, nginx, etc.) is not good at opening/closing a large number of connections instantaneously.
These connection errors are especially common in environments where the web server performs HTTPS encryption / decryption.
In such cases, actual web browser will retry the connections, but the JMeter client will not.
Such errors occur at network interface layer, and the service software cannot detect the error.
So that, the errors does not record in log files of service software and operating system, and administrators are less likely to notice the lack of performance of their web server.

We use Haproxy (load balancer) even under an environment of one Moodle web server, in order to avoid the errors.
And, our Haproxy performs HTTPS encryption / decryption.
Even in our environments, the same errors occur between the load balancer and the web server.
But, the Haproxy can retry connections, and our simulation will proceed normally.

Moodle versions 3.9 and 4.0
I have tried making a script for concurrent users taking quiz using HTTP test recorder.
I am not providing any csv file, just increasing the number of threads with single login and password for authorization.
The test ran successfully even without parameterizing the attempt id, session key and question number.
But the total attempts doesn't change on the servers as the attempt id is same for all threads.
Attempt id and question number is not getting captured in the response body. So not able to use post processor regular expression extractor.
How to capture both attempt id and question number in response body? and use regular expression extractor?