Re: host name support in pg_hba.conf

Magnus Hagander <magnus(at)hagander(dot)net> writes:
> On Wed, Oct 6, 2010 at 15:16, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
>> However, the usage in pgstat.c is hard-wired, meaning that if you
>> have a configuration where "localhost" doesn't resolve correctly
>> for whatever reason, there's no simple recourse to get the stats
>> collector working. So ISTM there is an argument for changing that.

> Well, hardcoding it will break the (unusual) case when localhost isn't
> 127.0.0.1 / ::1. (You'd obviously have to have it try both ipv4 and
> ipv6).

You didn't read what I wrote before. Those numeric addresses define the
loopback address, *not* "localhost". When localhost fails to resolve
as those address(es), it's localhost that is wrong. We have actually
seen this in the field with bogus DNS providers.

> It's not common, but i've certainly come across a number of virtual
> machines where localhost resolves (through /etc/hosts) to the machines
> "real" IP rather than 127.0.01, because 127.0.0.1 simply doesn't
> exist.

That appears to me to be a broken (non RFC compliant) VM setup.
However, maybe what this is telling us is we need to expose the setting?
Or perhaps better, try 127.0.0.1, ::1, localhost, in that order.

regards, tom lane