Re: Quorum commit for multiple synchronous replication.

On Fri, Apr 21, 2017 at 12:02 PM, Noah Misch <noah(at)leadboat(dot)com> wrote:
> On Wed, Apr 19, 2017 at 01:52:53PM +0900, Masahiko Sawada wrote:
>> On Wed, Apr 19, 2017 at 12:34 PM, Noah Misch <noah(at)leadboat(dot)com> wrote:
>> > On Sun, Apr 16, 2017 at 07:25:28PM +0900, Fujii Masao wrote:
>> >> On Sun, Apr 16, 2017 at 1:19 PM, Noah Misch <noah(at)leadboat(dot)com> wrote:
>> >> > On Fri, Apr 14, 2017 at 11:58:23PM -0400, Noah Misch wrote:
>> >> >> On Wed, Apr 05, 2017 at 09:51:02PM -0400, Noah Misch wrote:
>> >> >> > On Thu, Apr 06, 2017 at 12:48:56AM +0900, Fujii Masao wrote:
>> >> >>
>> >> >> > > > On Mon, Dec 19, 2016 at 09:49:58PM +0900, Fujii Masao wrote:
>> >> >> > > >> (3)
>> >> >> > > >> The priority value is assigned to each standby listed in s_s_names
>> >> >> > > >> even in quorum commit though those priority values are not used at all.
>> >> >> > > >> Users can see those priority values in pg_stat_replication.
>> >> >> > > >> Isn't this confusing? If yes, it might be better to always assign 1 as
>> >> >> > > >> the priority, for example.
>> >
>> >> >> This PostgreSQL 10 open item is past due for your status update. Kindly send
>> >> >> a status update within 24 hours, and include a date for your subsequent status
>> >> >> update. Refer to the policy on open item ownership:
>> >> >> https://www.postgresql.org/message-id/20170404140717.GA2675809%40tornado.leadboat.com
>> >
>> >> >> > Since you do want (3) to change, please own it like any other open item,
>> >> >> > including the mandatory status updates.
>> >> >>
>> >> >> Likewise.
>> >>
>> >> As I told firstly this is not a bug. There are some proposals for better design
>> >> of priority column in pg_stat_replication, but we've not reached the consensus
>> >> yet. So I think that it's better to move this open item to "Design Decisions to
>> >> Recheck Mid-Beta" section so that we can hear more opinions.
>> >
>> > I'm reading that some people want to report NULL priority, some people want to
>> > report a constant 1 priority, and nobody wants the current behavior. Is that
>> > an accurate summary?
>>
>> Yes, I think that's correct.
>
> Okay, but ...
>
>> FWIW the reason of current behavior is that it would be useful for the
>> user who is willing to switch from ANY to FIRST. They can know which
>> standbys will become sync or potential.
>
> ... does this mean you personally want to keep the current behavior? If not,
> has some other person stated a wish to keep the current behavior?

No, I want to change the current behavior. IMO it's better to set
priority 1 to all standbys in quorum set. I guess there is no longer
person who supports the current behavior.

Regards,

--
Masahiko Sawada
NIPPON TELEGRAPH AND TELEPHONE CORPORATION
NTT Open Source Software Center