Re: Quorum commit for multiple synchronous replication.

Ok, I got the point.

At Wed, 19 Apr 2017 17:39:01 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp> wrote in <20170419(dot)173901(dot)16598616(dot)horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>
> > >> | <para>
> > >> | Quorum-based synchronous replication is basically more
> > >> | efficient than priority-based one when you specify multiple
> > >> | standbys in <varname>synchronous_standby_names</> and want
> > >> | to synchronously replicate transactions to two or more of
> > >> | them.

"Some" means "not all".

> > >> | In the priority-based case, the replication master
> > >> | must wait for a reply from the slowest standby in the
> > >> | required number of standbys in priority order, which may
> > >> | slower than the rest.

Quorum-based synchronous replication is expected to be more
efficient than priority-based one when your master doesn't need
to be in sync with all of the nominated standbys by
<varname>synchronous_standby_names</>. While quorum-based
replication master waits only for a specified number of fastest
standbys, priority-based replicatoin master must wait for
standbys at the top of the list, which may be slower than the
rest.

regards,

--
Kyotaro Horiguchi
NTT Open Source Software Center