From: Bruce Momjian <pgman@candle.pha.pa.us>
Message-Id: <200504300352.j3U3qQT28497@candle.pha.pa.us>
Subject: Re: [COMMITTERS] pgsql: Remove replicaiton FAQ item.
In-Reply-To: <m3fyxgqhni.fsf@knuth.cbbrowne.com>
To: Christopher Browne <cbbrowne@acm.org>
Date: Fri, 29 Apr 2005 23:52:26 -0400 (EDT)
Cc: pgsql-docs@postgresql.org
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OK, updated:

    <P>Though "replication" is a single term, there are several technologies
    for doing replication, with advantages and disadvantages for each.</P>

    <P>Master/slave replication allows a single master to receive read/write
    queries, while slaves can only accept read/<SMALL>SELECT</SMALL> queries.
    The most popular freely available master-slave PostgreSQL replication
    solution is <A href="http://gborg.postgresql.org/project/slony1/projdisplay$
    Slony-I</A>.</P>

    <P>Multi-master replication allows read/write queries to be sent to
    multiple replicated computers.  This capability also has a severe
    impact on performance due to the need to synchronize changes between
    servers.  <A href="http://pgfoundry.org/projects/pgcluster/">Pgcluster</a>
    is the most popular such solution freely available for PostgreSQL.</P>

    <P>There are also commercial and hardware-based replication solutions
    available supporting a variety of replication models.</P>


---------------------------------------------------------------------------

Christopher Browne wrote:
> Martha Stewart called it a Good Thing when pgman@candle.pha.pa.us (Bruce Momjian) wrote:
> > Yep, big mistake my removing the replication FAQ item. I have re-added a
> > new one:
> >
> > 	4.21) What replication solutions are available?
> > 	
> > 	Though "replication" is a single term, there are two major replication
> > 	technologies. Multi-master replication allows read/write queries to be
> > 	sent to multiple replicated computers. Using this capability has a
> > 	serious performance impact. Pgcluster is the most popular such solution
> > 	available for PostgreSQL. Master-slave replication allows a single
> > 	master to receive read/write queries, with slaves able to accept only
> > 	read/SELECT queries. The most popular master-slave PostgreSQL
> > 	replication solution is Slony. There are also commercial and
> > 	hardware-based replication solutions available.
> 
> A suggestion for rewording:
> 
> Though "replication" is a single term, there are a number of
> approaches and technologies to handle it, and thus, for different
> purposes, a number of replication systems are available.
> 
> Master/slave replication allows a single master to receive read/write
> queries, where slaves can only accept read/SELECT queries.  The most
> popular freely available master-slave PostgreSQL replication solution
> is Slony-I.
> 
> Multi-master replication allows read/write queries to be sent to
> multiple replicated computers.  Using this capability generaly has a
> fairly severe impact on performance due to the need to synchronize
> changes between servers.  Pgcluster is the most popular such solution
> freely available for PostgreSQL.
> 
> There are also commercial and hardware-based replication solutions
> available supporting a variety of replication models.
> -- 
> (format nil "~S@~S" "cbbrowne" "acm.org")
> http://linuxdatabases.info/info/slony.html
> "It   can be   shown   that for any  nutty  theory,  beyond-the-fringe
> political view or  strange religion there  exists  a proponent  on the
> Net. The proof is left as an exercise for your kill-file."
> -- Bertil Jonell
> 
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