Re: [HACKERS] Quorum commit for multiple synchronous replication. - Mailing list pgsql-hackers

At Fri, 21 Apr 2017 13:20:05 +0900, Masahiko Sawada <sawada.mshk@gmail.com> wrote in
<CAD21AoCU+ch4b2O0iW-b_BnUs7oMcT8pcwM690XVu134k=cA+Q@mail.gmail.com>
> On Fri, Apr 21, 2017 at 12:02 PM, Noah Misch <noah@leadboat.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@leadboat.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@leadboat.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.

+1 for the latter. For the former, I'd like to distinguish
standbys in sync and not in the field or something if we can
allow the additional complexity.

regards,

-- 
Kyotaro Horiguchi
NTT Open Source Software Center