Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> writes:
> To set or clear the flag from PGPROC, to send or handle a signal, we
> have to acquire ProcArrayLock. Is that safe to do in a signal handler?
No. If it's trying to do that then it's broken. In fact, if it's
trying to do much of anything beyond setting a "volatile" flag variable
in a signal handler, it's broken --- unless there are special provisions
to limit where the signal trap can occur, which would be pretty much
unacceptable for a multiplexed-signal implementation.
regards, tom lane