Re: Quorum commit for multiple synchronous replication.

On Tue, Apr 25, 2017 at 12:56 AM, Fujii Masao <masao(dot)fujii(at)gmail(dot)com> wrote:
> On Mon, Apr 24, 2017 at 9:02 AM, Noah Misch <noah(at)leadboat(dot)com> wrote:
>> On Thu, Apr 20, 2017 at 11:34:34PM -0700, Noah Misch wrote:
>>> On Fri, Apr 21, 2017 at 01:20:05PM +0900, Masahiko Sawada wrote:
>>> > 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:
>>> > >> >> 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.
>>>
>>> In that case, this open item is not eligible for section "Design Decisions to
>>> Recheck Mid-Beta". That section is for items where we'll probably change
>>> nothing, but we plan to recheck later just in case. Here, we expect to change
>>> the behavior; the open question is which replacement behavior to prefer.
>>>
>>> Fujii, as the owner of this open item, you are responsible for moderating the
>>> debate until there's adequate consensus to make a particular change or to keep
>>> the current behavior after all. Please proceed to do that. Beta testers
>>> deserve a UI they may like, not a UI you already plan to change later.
>>
>> Please observe the policy on open item ownership[1] and send a status update
>> within three calendar days of this message. Include a date for your
>> subsequent status update.
>
> Okay, so our consensus is to always set the priorities of sync standbys
> to 1 in quorum-based syncrep case. Attached patch does this change.
> Barrying any objection, I will commit this.

+1

Regards,

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