On Thu, Apr 20, 2017 at 9:31 AM, Kyotaro HORIGUCHI <horiguchi.kyot...@lab.ntt.co.jp> wrote: > 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.
This description looks good to me. I've updated the patch based on this description and attached it. Regards, -- Masahiko Sawada NIPPON TELEGRAPH AND TELEPHONE CORPORATION NTT Open Source Software Center
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