NodeJS Architecture - I/O

Node is a non-blocking Javascript runtime. You can concurrently run an HTTP Server, read files from disk, send UDP datagrams, accept TCP connections from clients and still have room to execute Javascript code operations without blocking. Most of these operations are known as I/O, you send an input to a device, file or a socket and it replies back with an output. Node achieves non-blocking I/O with mostly a single thread executed asynchronously using a library called lib_uv. The exception being DNS queries, which use a thread pool. This means when you use fetch or axios to make an HTTP request to a domain, the DNS resolution for that domain will most probably go through the thread pool, while the actual request itself will be sent asynchronously on the main thread. In this episode of the backend engineering show I go through an article I wrote discussing NodeJS Asynchronous I/O. https://medium.com/@hnasr/when-nodejs-i-o-blocks-327f8a36fbd4 Learn the fundamentals of network engineering, get my udemy course https://network.husseinnasser.com 0:00 Intro 3:00 Part 1 Socket/IO 9:48 Part 2 File I/O 12:42 Part 3 DNS 16:22 Part 4 NodeJS Single Threaded 19:10 Part 5 NodeJS Thread Pool 21:23 Part 6 DNS lookup bottleneck in Node Fundamentals of Networking for Effective Backends udemy course (link redirects to udemy with coupon) https://network.husseinnasser.com Fundamentals of Database Engineering udemy course (link redirects to udemy with coupon) https://database.husseinnasser.com Introduction to NGINX (link redirects to udemy with coupon) https://nginx.husseinnasser.com Python on the Backend (link redirects to udemy with coupon) https://python.husseinnasser.com Become a Member on YouTube https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join Buy me a coffee if you liked this https://www.buymeacoffee.com/hnasr Arabic Software Engineering Channel https://www.youtube.com/channel/UChWZsjdoRvZ0T9QWZOD6UpA 🔥 Members Only Content https://www.youtube.com/playlist?list=UUMO_ML5xP23TOWKUcc-oAE_Eg 🏭 Backend Engineering Videos in Order https://backend.husseinnasser.com 💾 Database Engineering Videos https://www.youtube.com/playlist?list=PLQnljOFTspQXjD0HOzN7P2tgzu7scWpl2 🎙️Listen to the Backend Engineering Podcast https://husseinnasser.com/podcast Gears and tools used on the Channel (affiliates) 🖼️ Slides and Thumbnail Design Canva https://partner.canva.com/c/2766475/647168/10068 Stay Awesome, Hussein