Stelios Malathouras <s.malathouras@deltasoftsolutions.net> writes:
> Our local tests, with listen_addresses = '*', show that the postgres listener accepts connections immediately to the
newIP.
> The same behavior is observed when adding a new network interface. Postgres accepts connections to the new network
interface(and IP) immediately without requiring a restart.
It might be platform-dependent. We call getaddrinfo(3) only once at
postmaster start, passing node = NULL if you said "*", and then
bind(2) to each resulting address. The Linux manpage for getaddrinfo
quoth
If the AI_PASSIVE flag is specified in hints.ai_flags, and node is
NULL, then the returned socket addresses will be suitable for
bind(2)ing a socket that will accept(2) connections. The returned
socket address will contain the "wildcard address" (INADDR_ANY for IPv4
addresses, IN6ADDR_ANY_INIT for IPv6 address). The wildcard address is
used by applications (typically servers) that intend to accept connec‐
tions on any of the host's network addresses.
The POSIX standard for getaddrinfo also says that these parameters
yield a wildcard address, but it doesn't say in so many words that
that results in accepting connections on any of the machine's
interfaces. Maybe it says that elsewhere, though; I didn't go
digging. In any case, you're probably fine on any Linux box,
but if you want to rely on this behavior on some other platform
I'd advise testing first.
regards, tom lane
