2025-01-19 · Go

Compare goroutines and a worker pool

Fan-out looks great until one slow job takes down your latency budget.

Introduction

Spawning a goroutine per request is idiomatic and dangerous at the same time. We measure unbounded concurrency against a bounded pool, then size the queue from real numbers instead of intuition.

Field notes

A few patterns we kept seeing while puttering around Go problems:

  • The simple version survived every refactor; the clever version didn’t.
  • Documentation written during the work aged far better than documentation written after.
  • The second time a problem shows up, it is already a pattern — name it.

A checklist you can steal

  • The failure is reproducible with one command.
  • The fix has a test that fails without it.
  • Someone other than the author has run it on their machine.

Closing

Write the short version future-you will actually read. That is the whole trick.