What happens when a single request takes a long time with these non-blocking I/O servers?

Question

With Node.js, or eventlet or any other non-blocking server, what happens when a given request takes long, does it then block all other requests?

Example, a request c

Answer 1

Everything in node.js runs in parallel internally. However, your own code runs strictly serially. If you sleep for a second in node.js, the server sleeps for a second. It's not suitable for requests that require a lot of computation. I/O is parallel, and your code does I/O through callbacks (so your code is not running while waiting for the I/O).

On most modern platforms, node.js does us threads for I/O. It uses libev, which uses threads where that works best on the platform.