Re: confusion about user paring with pg_hba and pg_ident

On Tue, Oct 11, 2016 at 4:20 PM Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:

> arnaud gaboury <arnaud(dot)gaboury(at)gmail(dot)com> writes:
>
> > I am a little confused about some of my settings when it comes to map
>
> > linux/psql users.
>
>
>
> I think you're misunderstanding what the user-mapping stuff does.
>
> It does not silently translate the username in the connection request
>
> to something else; rather, it checks whether a user having the given
>
> external name is allowed to log in as a particular Postgres user.
>
> So there's nothing particularly wrong with your config files, but your
>

Then, if my files are correct, why can't I connect ?

% psql --dbname=mattermost --username=mmuser
psql: FATAL: Peer authentication failed for user "mmuser"

login with postgres is OK (pg_hba.conf settings: local
all postgres trust):
% psql --dbname=mattermost --username=postgres
psql (9.5.4)
Type "help" for help.

mattermost=# \q

I can't see why I can't connect as Postgresuser mmuser.

> expectation about how your Linux users should log in to the database is
>
> mistaken. dovecot needs to specify that it wants to log in as mailman,
>
> and likewise mattermost needs to specify mmuser.
>
>
>
> If it's not practical to make the client applications send non-default
>
> user names, you'll need to rename the Postgres roles to match the
>
> external user names.
>
>
>
> regards, tom lane
>
>