Re: Logical Replication WIP

On 2016-09-12 21:57:39 +0200, Petr Jelinek wrote:
> On 12/09/16 21:54, Andres Freund wrote:
> > On 2016-09-12 21:47:08 +0200, Petr Jelinek wrote:
> > > On 09/09/16 06:33, Peter Eisentraut wrote:
> > > > The start_replication option pg_version option is not documented and
> > > > not used in any later patch.  We can probably do without it and just
> > > > rely on the protocol version.
> > > > 
> > > 
> > > That's leftover from binary type data transfer which is not part of this
> > > initial approach as it adds a lot of complications to both protocol and
> > > apply side. So yes can do without.
> > 
> > FWIW, I don't think we can leave this out of the initial protocol
> > design. We don't have to implement it, but it has to be part of the
> > design.
> > 
> 
> I don't think it's a good idea to have unimplemented parts of protocol, we
> have protocol version so it can be added in v2 when we have code that is
> able to handle it.

I don't think we have to have it part of the protocol. But it has to be
forseen, otherwise introducing it later will end up requiring more
invasive changes than acceptable. I don't want to repeat the "libpq v3
protocol" evolution story here.