On ons, 2010-08-11 at 09:55 -0400, Tom Lane wrote:
> BTW, I don't know why anyone would think that "a random number" would
> offer any advantage here. I'd use the postmaster PID, which is
> guaranteed to be unique across the space that you're worried about.
> In fact, you could implement this off the existing postmaster.pid,
> no need for any new file. What's lacking is the pg_ping protocol.
Why not just compare pg_backend_pid() with postmaster.pid?