5.5 Fail Fast
If slow responses are worse than no response, the worst must surely be a slow failure response. It’s like waiting through the interminable line at the DMV, only to be told you need to fill out a different form and go back to the end of the line. Can there be any bigger waste of system resources than burning cycles and clock time only to throw away the result?
If the system can determine in advance that it will fail at an operation, it’s always better to fail fast. That way, the caller doesn’t have to tie up any of its capacity waiting; it can get on with other work.
How can the system tell whether it will fail? What kind of secret ...