Fix MemoryError in Go in Production

Go Memory Issues in Production

Go doesn't throw "MemoryError" like Python — instead, the runtime panics with runtime: out of memory or the OS kills the process. Here's how to diagnose and fix it.

Enable pprof

Add the profiling endpoint to your service:

import _ "net/http/pprof"

func main() {
    go func() {
        log.Println(http.ListenAndServe(":6060", nil))
    }()
    // ... your main server
}

Then capture a heap profile:

go tool pprof http://localhost:6060/debug/pprof/heap
(pprof) top 10

Goroutine Leaks

The most common Go memory issue — goroutines that never exit:

// LEAK: goroutine blocked forever if ctx is never cancelled
func startWorker(ch chan Data) {
    go func() {
        for data := range ch {
            process(data)
        }
    }()
    // If ch is never closed, this goroutine lives forever
}

// FIX: use context for cancellation
func startWorker(ctx context.Context, ch chan Data) {
    go func() {
        for {
            select {
            case data, ok := <-ch:
                if !ok { return }
                process(data)
            case <-ctx.Done():
                return
            }
        }
    }()
}

Large Allocations

// BAD — allocates entire file in memory
data, _ := os.ReadFile("huge.csv")

// GOOD — stream it
file, _ := os.Open("huge.csv")
scanner := bufio.NewScanner(file)
for scanner.Scan() {
    processLine(scanner.Text())
}

Check goroutine counts in production:

curl http://localhost:6060/debug/pprof/goroutine?debug=1 | head -5

Bugsly captures Go panics including runtime: out of memory with goroutine dumps, making it easy to see which goroutines were running when memory ran out.