/tmp is for *temporary* files. Such a lock is not a temporary file, it
should go somewhere in /var, why not in /var/lib/pgsql/data ?
> The 'tmpwatch' program on Red Hat will remove the /tmp/.s.PGSQL.5432.lock
> file after the server has run 6 days. This will be a problem.
>
> We could touch (open) the file once every time the ServerLoop() runs
> around. It's not perfect but it should work in practice.