Lightning Talk: The debugging tool that comes with Erlang/OTP I just learned
summary
An overlooked built‑in per‑process ring buffer stores the last N external calls and message events and is enabled with process_flag(save_calls, N) (it’s been in OTP since R16). Query it with process_info(Pid, last_calls) or view the same list in observer and crash dumps; entries show module/function/arity tuples plus send/receive/timeout markers. Demo shows setting 32 entries returns the old value and immediately exposes a concise call trace for debugging concurrent processes.
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chapters (8)
- 0:00Erlang OTP debugging tools
- 2:05Traditional debugging limits
- 3:31Debug tracing power
- 5:17Process flag save_calls
- 6:21Demo: save_calls
- 9:36Audience awareness
- 10:41Q&A
- 11:01OTP tools gems
