Race conditions

Race conditions

What are race conditions and why do they happen?

I won't lie, I often heard the term race conditions but always assumed I understood what it meant, but when I tried to explain it, I just couldn't find the right words. I've always understood race conditions, speaking in the context of making network requests, as an undesired behavior that occurs when multiple requests are in-flight that modify the same or similar things.

This has always been an assumption of mine though, hence I dug into what race conditions really are and wrote this article.

Race conditions

By definition: A race condition happens when two or more operations are happening at the same time, and compete for which one will be executed first.

Race conditions are common in multi-threaded applications.

Race conditions can cause unexpected bugs or behaviors in our programs.

I made a visual below. Let's say for instance user spam clicks a button that makes requests to the server.

Screenshot from 2022-09-20 06-25-39.png


At least my understanding of race conditions is more clear, and I hope yours too.