Re: pg.el: pg:connect -> Backend error: FATAL unsupported frontend protocol 1.0: server supports 2.0 to 3.0

[Jean Louis <bugs@gnu.support>]

On Mon, Nov 26, 2018 at 10:48:27AM +0100, Martin Steffen wrote:
> I encountered a problem with postgres/pg.el after a recent upgrade of
> the OS (fedora/postgres). It well might be that pg.el is not the
> ``culprit'' but I was not able to properly nail it down and I don't know
> how to localize is.
> 
> On a very high level, the problem is: connecting to an existing data base
> via pg.el yields the message
> 
> --------------------------
>     pg:connect: Backend error: FATAL:  unsupported frontend protocol 1.0: server supports 2.0 to 3.0    

Hello Martin,

I cannot say that this may help you. But I do
remember I had similar problem.

I am user of PostgreSQL who often installs it
myself, not by distribution and I sometimes
install one version more than what distribution
offers me.

So before months I have encountered the same
problem.

Read more about it here:
https://github.com/anse1/emacs-libpq/issues/7

Thus in the version 10 or 10.1 the protocol 1.0
has been dropped. So pg.el does not work any more,
unless somebody updates it.

My solution was to install that same module libpq
which does the work just well since 10 months
without problems.

https://github.com/anse1/emacs-libpq

Packages depending on pg.el may not work. But they
can be easily updated or modified.

I guess that the more users start using new
version of PostgreSQL there will be more reports
on how pg.el does not work any more.

Jean Louis