Major Description
The message might look like this:
{"statement":"use default; show table extended like xyz;","error":"unable to show table: xyz","exec":{"stdout":"","stderr":"","exitcode":143}}
WebHCat has a templeton.exec.timeout property which kills an HCat request (i.e. something like a DDL statement that gets routed to HCat CLI) if it takes longer than this timeout.
Since WebHCat does a fork/exec to 'hcat' script, the timeout is implemented as SIGTERM sent to the subprocess. SIGTERM value is 15. So it's reported as 128 + 15 = 143.
Error logging/reporting should be improved in this case.