As mentioned earlier, Redis takes great advantage of the non-blocking, multiplexing I/O model in its main processing single thread, although there are some circumstances where Redis spawns threads or child processes to perform certain tasks.
Redis contains a simple but powerful asynchronous event library called ae to wrap different operating system's polling facilities, such as epoll, kqueue, select, and so on.
So what's a polling facility of an operating system? Let's take a real-life scenario to illustrate it. Imagine you have ordered five dishes in a restaurant. You have to fetch your dishes by yourself at a waiting window, and you want to get them as soon as possible once the dishes get done because you are hungry. You ...
