Re: What (not) to do in signal handlers

ncm@zembu.com (Nathan Myers) writes:
> It could open a pipe, and write(2) a byte to it in the signal handler, 
> and then have select(2) watch that pipe.  (SIGHUP could use the same pipe.)
> Of course this is still a system call in a signal handler, but it can't
> (modulo coding bugs) fail.

Hm.  That's one way, but is it really any cleaner than our existing
technique?  Since you still need to assume you can do a system call
in a signal handler, it doesn't seem like a real gain in
bulletproofness to me.

> A pipe per backend might be considered pretty expensive.

Pipe per postmaster, no?  That doesn't seem like a huge cost.  I'd be
more concerned about the two extra kernel calls (write and read) per
signal received, actually.
        regards, tom lane