On Tue, 2010-06-08 at 16:47 -0400, Robert Haas wrote: > On Thu, May 27, 2010 at 9:22 AM, Heikki Linnakangas > <heikki.linnakan...@enterprisedb.com> wrote: > > On 27/05/10 12:39, Dimitri Fontaine wrote: > >> > >> Greg Stark<gsst...@mit.edu> writes: > >>> > >>> Fwiw I like the word "replica" but I don't see an obvious choice of > >>> word to pair it with > >> > >> I guess it's replica / origin, per choice of Jan Wieck to be found in > >> our catalogs: > >> > >> http://www.postgresql.org/docs/current/static/catalog-pg-trigger.html > >> > >> tgenabled char > >> > >> Controls in which session_replication_role modes the trigger fires. > >> O = trigger fires in "origin" and "local" modes, D = trigger is > >> disabled, R = trigger fires in "replica" mode, A = trigger fires > >> always. > >> > >> So that's origin/replica, master/slave, primary/standby, master/standby. > > > > master/standby is my favorite, and I believe we have a rough consensus on > > that. > > > > I started to search/replace primary -> master, but started to have second > > thoughts when I got to the section in the docs about standby servers: > > > > http://developer.postgresql.org/pgdocs/postgres/warm-standby.html > > > > Somehow that just doesn't sound as good after s/primary/master, the first > > sentence in particular. I think the reason is that "master" brings to mind > > an active connection between the master and standby, while "primary" sounds > > more loosely-coupled. > > > > Perhaps we should use master/standby when discussing streaming replication, > > and primary/standby when talking about a standby setup in general, possibly > > using file-based log shipping. The distinction is quite vague, so we'll have > > to document both terms as synonyms of each other. > > I agree. I think it might make sense to try to standardize on the use > of "master" in messages (and GUC variable names) but insisting that we > can never say "primary" in the docs would make them read very oddly, I > think.
The reasons the two sets of terms exist is that they aren't completely opposed. Master/slave is talking about who makes the changes and who accepts them, whereas primary/standby is talking about who is currently active and who is available to become active if required. Slony also talks about origin/subscriber. SR also uses sender/receiver. Which metaphor we use depends upon which aspect of the system we use. We could have chosen not to introduce send/receive, but its so obvious and natural for SR that its worth introducing new terms. Master/standby sounds like a mixed metaphor to me and harder to understand as a result. -- Simon Riggs www.2ndQuadrant.com -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
