Re: v12 pg_basebackup fails against older servers (take two)

On Tue, Oct 22, 2019 at 12:32:53PM +0300, Devrim Gündüz wrote:
> When I run pg_basebackup in v12 against v11, standby server fails to connecto
> primary with the following error:
>
> 2019-10-22 09:28:23.673 UTC [2375] FATAL:  could not connect to the primary
> server: invalid connection option "gssencmode"
>
> When I remove this from recovery.conf, it works fine. Looks like a bug to me
> (we need to preserve backward compatibility). Comments?

You are referring to the connection string generated in
primary_conninfo here, right?  It would be nice to be more compatible
here.  This can be simply fixed by having an extra filter in
GenerateRecoveryConfig() (different file between HEAD and
REL_12_STABLE).  I also think that there is more.  On HEAD,
channel_binding gets added to the connection string generated which
would equally cause a failure with pg_basebackup from HEAD used for a
v12 or older server.
--
Michael