As someone who's been programming professionally for several years, I'm embarrassed to admit that I barely have any experience with concurrent programming. My next project heavily relies on database and network sync, so I figured it would be a good opportunity to brush up on the basics. I'm currently trying to internalize the inner workings of a popular open-source database project (YapDatabase), but I've run into a significant mental block: whenever I try to visualize the flow of a concurrent program in time, I just can't seem to keep it in my head. With single-threaded programming, things are a lot easier. Control flow is predictable and circuit-like, allowing you to draw the structure of most programs out on paper. But it seems that with concurrency, you're essentially adding a third dimension to the mix: not something that can easily be represented in 2D space! Whenever I have to reason about overlapping thread interactions, obscure deadlock conditions, and synchronization summersaults, I just feel like I immediately get lost and have to start over. There's no stable structure for me to grab onto: every overlap of the threads in time has to be considered!<p>I know this is possibly too general of a question, but is there a systematic approach to reasoning about concurrent programs?<p>(In the meantime, I suppose I'm going to keep reading the code over and over and hope that things start to stick.)