Since our default behavior (at startup) is to have TCP sockets disabled,
how many OSs are there that don't support UD sockets? Enough to really be
worried about?
On Mon, 6 May 2002, Tom Lane wrote:
> "Marc G. Fournier" <scrappy@hub.org> writes:
> >> That would work ... but is it more portable than depending on SysV
> >> shmem connection counts? ISTR that some of the platforms we support
> >> don't have Unix-style sockets at all.
>
> > Wouldn't the same thing work with a simple file? Does it have to be a
> > UnixDomainSocket?
>
> No, and yes. If it's not a pipe/fifo then you don't get the
> EOF-only-when-no-possible-writers-remain behavior. TCP and UDP
> sockets don't show this sort of behavior either. So AFAICS we
> really need a named pipe, ie, socket.
>
> We could maybe do something approximately similar with TCP connection
> attempts (per the prior suggestion of letting backends hold the
> postmaster's listen socket open; then see if you get "connection
> refused" or a timeout from trying to connect) but I don't think it'd be
> as trustworthy. Simple mistakes like overly aggressive ipchains filters
> would confuse this kind of test.
>
> regards, tom lane
>