Ok, I got the point. At Wed, 19 Apr 2017 17:39:01 +0900 (Tokyo Standard Time), Kyotaro HORIGUCHI <horiguchi.kyot...@lab.ntt.co.jp> wrote in <20170419.173901.16598616.horiguchi.kyot...@lab.ntt.co.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 -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
