What does time specified in a stack trace mean?

Question

I'm reading stack trace of a go program for debugging.

goroutine 6 [chan receive]:
go.elastic.co/apm.(*Tracer).loop.func2(0xc000042420, 0xc0000423c0, 0x1551980, 0xc0004da100, 0xc000074300, 0xc000001080, 0xc00000e018)
    /app/vendor/go.elastic.co/apm/tracer.go:803 +0x21a
created by go.elastic.co/apm.(*Tracer).loop
    /app/vendor/go.elastic.co/apm/tracer.go:800 +0x36e

goroutine 8 [chan receive, 21 minutes]:
github.com/getsentry/sentry-go.(*HTTPTransport).worker(0xc0003025b0)
    /app/vendor/github.com/getsentry/sentry-go/transport.go:387 +0x77
created by github.com/getsentry/sentry-go.(*HTTPTransport).Configure.func1
    /app/vendor/github.com/getsentry/sentry-go/transport.go:255 +0x3e

What does the time 21 minutes signify in the second go routine? This time is absent from the first one. I looked up in the documentation but couldn't find what this time is for.

Answer 1

It's the approximate amount of time the goroutine was blocked. It is only displayed if the amount of time the goroutine was blocked is at least 1 minute.

You can look at the code that produces this output in the go runtime source, runtime/traceback.go (linked is the go1.16.6 version of the code).