How can I be sure that wrk is targeting different profile ids?

Question

I'm doing performance testing and using wrk for the first time. My goal is to send requests to different profile ids because I suspect the platform being tested caches same request so that response times improve. URL looks something like this:

http://some_url:some_port/cxs/profiles/...

Made a LUA script to randomize profile ids that looks like this:

request = function()   
return wrk.format(nil, string.format("/cxs/profiles/%012d", math.random(100000000)))
end

and my wrk request looks like this:

 wrk -t3 -c8 -d15m -H "Authorization: Basic a2FyYWY6a2FyYWY=" -s myScript.lua "http://some_url:some_port" --latency 

Is there a way to be sure that wrk is really targeting different profile ids? Because the response time doesn't change a lot without the script

Answer 1

I've found out that adding math.randomseed(os.time()), you make sure that the math.random() function generates new random number every time.