Re: Quorum commit for multiple synchronous replication.

On Thu, Dec 15, 2016 at 6:47 AM, Michael Paquier
<michael(dot)paquier(at)gmail(dot)com> wrote:
> On Wed, Dec 14, 2016 at 11:34 PM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
>> If we drop the "standby_list" syntax, I don't think that new parameter is
>> necessary. We can keep s_s_names and just drop the support for that syntax
>> from s_s_names. This may be ok if we're really in "break all the things" mode
>> for PostgreSQL 10.
>
> Please let's not raise that as an argument again... And not break the
> s_list argument. Many users depend on that for just single sync
> standbys. FWIW, I'd be in favor of backward compatibility and say that
> a standby list is a priority list if we can maintain that. Upthread
> agreement was to break that, I did not insist further, and won't if
> that's still the feeling.

I wonder why you think that the backward-compatibility for standby_list is
so "special". We renamed pg_xlog directory to pg_wal and are planning to
change recovery.conf API at all, though they have bigger impacts on
the existing users in terms of the backward compatibility. OTOH, so far,
changing GUC between major releases happened several times.

But I'm not against keeping the backward compatibility for standby_list,
to be honest. My concern is that the latest patch tries to support
the backward compatibility "partially" and which would be confusing to users,
as I told upthread.

So I'd like to propose to keep the backward compatibility fully for s_s_names
(i.e., both "standby_list" and "N (standby_list)" mean the priority method)
at the first commit, then continue discussing this and change it if we reach
the consensus until PostgreSQL 10 is actually released. Thought?

Regards,

--
Fujii Masao