Node.js · Senior · Question 13 of 75

When does increasing `UV_THREADPOOL_SIZE` actually help?

1When JavaScript code is CPU-bound
2When there are many slow HTTP requests to other services
✓Correct answer: When many concurrent fs, dns.lookup, crypto.pbkdf2/scrypt or zlib calls queue up behind the default 4 threads

Explanation

Network sockets don't use the pool, and JavaScript always runs on the main thread. For CPU-bound JS, use worker threads.

Further reading

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