When is NodeJS Single Threaded and when is it multi-Threaded?

The Backend Engineering Show with Hussein Nasser

0:00

-9:36

When is NodeJS Single Threaded and when is it multi-Threaded?

Hussein Nasser

Mar 24, 2021

Node JS Is single-threaded asynchronous non-blocking javascript runtime, but it's not always single-threaded there are occasions where nodejs uses multi-threading, so the questions we will try to answer in this video, when is nodejs single-threaded and when does it use multi-threading and how will that affect my app?

Event Loop single thread, that really just loops for callbacks 0:00
Threading in Node jS (libuv) 4:00
- used for
- IO/intensive
  - DNS queries
  - file system reads
- CPU intensive
  - crypto
  - compression
- process.env.UV_THREADPOOL_SIZE=1

Examples 8:00

Cluster Nodejs 16:00

Example 1

HTTP server return 1

HTTP server while 1

HTTP server with file system read async

HTTP server with file system read sync

HTTP server with fetch call to server (dns)

Support my work on PayPal

https://bit.ly/33ENps4

Become a Member on YouTube

https://www.youtube.com/channel/UC_ML5xP23TOWKUcc-oAE_Eg/join