#goroutines

Programming Languages Bug Report

Go service OOM-killed under a traffic burst: one goroutine per request to a slow dependency

Lucas Moreau · Nov 3, 2025 · 7 min read

A Go ingestion service that forwarded events to a partner API was OOM-killed every time traffic spiked. Each event started a goroutine that waited on the slow partner, so goroutines and their buffers grew without limit. How we found it with pprof and fixed it with a bounded worker pool.

Programming Languages Bug Report

Go goroutines all processed the last item: loop variable capture and go.mod

Daniel Tran · Jan 21, 2025 · 8 min read

A reminder job sent 380 emails to one customer and none to the rest. The code was correct under Go 1.22 loop semantics, but the module's go.mod still said go 1.20, so every goroutine shared one loop variable. Here is the full trace and fix.