alt Hacker NewsTip: Web requests should not be measured in Hz [Hertz]
Comments
Copying my comment from the other recent thread:
The authority on the definition of SI units is very clear:
> The hertz shall only be used for periodic phenomena and the becquerel shall only be used for stochastic processes in activity referred to a radionuclide
Usually, no radionuclides are involved in web requests.
I've always used requests / second (or minute, etc) and that never seemed to be controversial. Why is there the need to find a different unit?
Counterpoint: let's say we connect a speaker to the HTTP server, and every time there's a request, the speaker produces a click. This setup will make audible sound. If it's OK to measure this sound in Hz, then is't OK to measure the HTTP requests in Hz, because they're explicitly === sound in this case.
Anyone else got served a page with garbage content meant for AI scrapers?
We don't use unit of measurements. We use metrics because we have a lot more context. Rps, requests per second is a commonly used unit but it has no defined standard, you could and often do average it over time for reporting but no one says you have to. For scaling however you'll probably want to use the max not the average, because no one wants a web application where in business as usual 60% of the time it works every time.
PSA: units never belong in square brackets.
[R] = Ohm
Never [Ohms]
Just use rps
We should use Sievert. I.e. how is the speed affecting my UX. That may depend on how much I give a fuck about the site multiplied by how many requests are needed to render it.
The Bq suggestion doesn’t actually fix anything. Becquerel is defined as one decay event per second and is dimensionally identical to Hz. Using Bq typically signals that a poisson process is being measured which is itself an assumption about the arrival statistics. This assumption is likely wrong for real web traffic (which tends to be bursty rather than memoryless).
More importantly, the claim that Hz is inappropriate for non-periodic phenomena is false. Many random processes have a well-defined Fourier transform, and reporting the intensity of random fluctuations in a frequency-range is standard across signal processing, neuroscience, finance, and physics. The unit doesn’t imply periodicity of the process itself. It implies that we are working in the Fourier domain, which applies as much to periodic signals as to stochastic processes.
If you want to characterize web request traffic properly, the right question is what the arrival process actually looks like. A single scalar whether in Hz or Bq throws away almost all of that. In all cases, you have to think carefully what your underlying assumptions are and what the reported number actually measures.