Re: Quorum commit for multiple synchronous replication.

At Tue, 25 Apr 2017 21:21:29 +0900, Masahiko Sawada <sawada.mshk@gmail.com> wrote in <CAD21AoBqpMzQ3hnLjOrAj1PX__Bqo9XWUhSX9hzAewdbQP9QKg@mail.gmail.com>
> On Tue, Apr 25, 2017 at 8:07 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
> > On Tue, Apr 25, 2017 at 2:09 PM, Kyotaro HORIGUCHI
> > <horiguchi.kyotaro@lab.ntt.co.jp> wrote:
> >>
> >> I'm not good at composition, so I cannot insist on my
> >> proposal. For the convenience of others, here is the proposal
> >> from Fujii-san.
> >>
> >
> > Do you see any problem with the below proposal?
> > To me, this sounds reasonable.
> 
> I agree.

Ok, I give up:p Thanks for shoving me.

> >> +     A quorum-based synchronous replication is basically more efficient than
> >> +     a priority-based one when you specify multiple standbys in
> >> +     <varname>synchronous_standby_names</> and want to replicate
> >> +     the transactions to some of them synchronously. In this case,
> >> +     the transactions in a priority-based synchronous replication must wait for
> >> +     reply from the slowest standby in synchronous standbys chosen based on
> >> +     their priorities, and which may increase the transaction latencies.
> >> +     On the other hand, using a quorum-based synchronous replication may
> >> +     improve those latencies because it makes the transactions wait only for
> >> +     replies from the requested number of faster standbys in all the listed
> >> +     standbys, i.e., such slow standby doesn't block the transactions.
> >>
> >
> > Can we do few modifications like:
> > improve those latencies --> reduce those latencies
> > such slow standby --> a slow standby
> >
> > --
> > With Regards,
> > Amit Kapila.
> > EnterpriseDB: http://www.enterprisedb.com
> 
> 
> Regards,
> 
> --
> Masahiko Sawada
> NIPPON TELEGRAPH AND TELEPHONE CORPORATION
> NTT Open Source Software Center

-- 
Kyotaro Horiguchi
NTT Open Source Software Center