>In my opinion, this feature could be usefull.
TL;DR: I don't try to prove that the feature is bad. I just don't have
motivation to implement this particular feature, so I list several corner
cases when the feature can behave unexpectedly if implemented in a naive
way.
Let me take a step back.
Here are some corner cases when "adjust timers" feature might harm:
1) Throughput timers. If a timer is set to maintain X requests per second,
then "adjust timers" feature should not adjust that timer. Otherwise the
throughput would be way off.
There is at least one such timer in JMeter core.
2) Suppose there's an AJAX application, and there's natural duration
between "the first HTML page, and the subsequent AJAX request". I mean it
takes some time for the browser to parse the initial page, and only then
AJAX requests are sent. In order to reflect that JMeter would have some
timer to implement the delay.
"adjust timers" feature should not impact that delay.
Note: I don't think this particular type of delay can easily be
distinguished from true inter-page delays when doing automatic recording.
3) Service timers that are used to implement "wait for the task" pattern.
I mean:
while(!task_ready) {
sleep(1 min);
refresh(home screen);
}
I happen to see that pattern quote often.
That particular "sleep(1min)" should not be "adjusted" (multiplied or
whatever) since that particular timer is not related to user behavior, but
it just lets the system to process the data.
So, the problem is "timer's java class" is the same yet the meaning (adjust
or not) is different.
4) There might be user-created timers those are completely unknown to
JMeter. Something should be done for the timers as well.
5) Some good wording in documentation is required to make it clear for the
end-user when the feature should be used, and when it should not be used.
Of course, every feature can be misused, so "theoretical misuse" should not
serve as a reason to deny a feature. However, the particular "adjust
timers" can very easily be confused with "tune throughput" feature. As
discussed, "throughput" should be tuned by the proper throughput timers.
Vladimir
