Re: postgresql-R

On Mar 7, 2006, at 2:58 PM, Louis Gonzales wrote:

> Based on:
> Postgres based Replication Projects
>
> PG Replication
> Postgres-R: Dr. Kemme's Site, Paper, Publications, Replication
> Work, The Horus Project and Emsemble
> DRAGON: Database Replication based on Group Communication
> The Slony-1 Project
> PGCluster
> DBBalancer
> PostgreSQL Replicator: Tutorial, Paper, Techdocs
> eRServer: Techdocs
> DBMirror: Will be in the 7.3 contrib directory.
> Usogres: Techdocs
> From: http://gborg.postgresql.org/project/pgreplication/
> genpage.php?replication_research
> I was under the impression that "Postgres-R" - I misspelled it as
> "postgresql-R" - is a database clustering software. I downloaded
> the sources for this and it's supposed to work with "spread." I
> apologize if I'm mistaken?

Well, AfAIK it's quasi-clustering. I'd describe it as a mix between
sync and async multi-master replication. Its concepts are the basis
behind Slony-II AFAIK.

> I will certainly take a look into Slony-1, as you suggest. Did you
> have any good links to this? Have you gone through an install on
> Solaris 9 w/Postgresl v8.0?
>
> WAN != LAN, where my database server is not in the same city as the
> target system to cluster with; for my worse case scenario, could be
> from east coast to west coast.

The issues you'll run into are that in a high-load scenario, the
latency on that link could become a real issue, as could bandwidth
(actually, bandwidth is probably the bigger issue). The other
downside is that slony is decidedly async; if you have to fail over
you're probably going to lose some recently committed data. As long
as that's not an issue then it's your best bet. If it is an issue,
you'll probably be stuck rolling your own solution using something
like 2PC.

You should hop on the slony mailing list if you have any questions
about it.
--
Jim C. Nasby, Sr. Engineering Consultant jnasby(at)pervasive(dot)com
Pervasive Software http://pervasive.com work: 512-231-6117
vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461