Re: PGCluster-II Progress

Yeah, the problem here is that CyberCluster is based yet on PostgreSQL 8.1 and is a very old version to use it.

I found the developer of PgCluster-II: Atsushi MITANI - mitani(at)sraw(dot)co(dot)jp

"The hurry is enemy of the success: for that reason.......Be patient"

Ing. Marcos L. Ortiz Valmaseda
Línea Soporte y Despliegue
Centro de Tecnologías de Almacenamiento y Análisis de Datos (CENTALAD)

Linux User # 418229
PostgreSQL User
http://www.postgresql.org
http://www.planetpostgresql.org/
http://www.postgresql-es.org/

----- Mensaje original -----
De: "Serge Fonville" <serge(dot)fonville(at)gmail(dot)com>
Para: "Marcos Luis Ortiz Valmaseda" <mlortiz(at)uci(dot)cu>
CC: "pgsql-hackers" <pgsql-hackers(at)postgresql(dot)org>
Enviados: Martes, 15 de Septiembre 2009 1:32:37 GMT -10:00 Hawai
Asunto: Re: [HACKERS] PGCluster-II Progress

I had the same question a while a go.
After a lot of googling I found http://www.cybertec.at/english/start_e.html
This seems to be an active replacement for the dead? pg-cluster

HTH

Regards,

Serge Fonville

On Tue, Sep 15, 2009 at 1:29 PM, Marcos Luis Ortiz Valmaseda < mlortiz(at)uci(dot)cu > wrote:

I was searching info about PgCluster-II yesterday and there is not much information about it.
Do can give to me any report of this? Because I need to know the progress of the project.
On PgFoundry, only it talks about PgCluster-1.9, but not of the 2.x versions.

Who is the PgCluster-II´s developer?

Regards

"The hurry is enemy of the success: for that reason.......Be patient"

Ing. Marcos L. Ortiz Valmaseda
Línea Soporte y Despliegue
Centro de Tecnologías de Almacenamiento y Análisis de Datos (CENTALAD)

Linux User # 418229
PostgreSQL User
http://www.postgresql.org
http://www.planetpostgresql.org/
http://www.postgresql-es.org/

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On Tue, Sep 15, 2009 at 7:48 AM, Marcos Luis Ortiz Valmaseda <mlortiz(at)uci(dot)cu
> wrote:

> Yeah, the problem here is that CyberCluster is based yet on PostgreSQL 8.1
> and is a very old version to use it.
>
> I found the developer of PgCluster-II: Atsushi MITANI - mitani(at)sraw(dot)co(dot)jp

Yeah, AFAICS, PGCluster II is and has been dead for years.

I did an architectural review of PGCluster II while at EnterpriseDB, and
it's never going to work from a performance perspective. Unfortunately, the
architecture (as it stands) requires coordination of pretty much all locks
and semaphores, and will only run on a single system because it requires a
nearly-identical shared memory segment for each instance. Unlike Oracle
RAC, which was designed to be run on separate nodes and share/coordinate
only relevant resources, PGCluster II coordinates almost everything
(transaction ids, buffer locks, etc.).

As an example, Oracle doesn't need to communicate with every node in the
cluster to generate a new transaction id (SCN in Oracle parlance) because it
employs a system based on Lamport timestamps, but PGCluster II has to
coordinate a global transaction id across all nodes.

Also, PGCluster II has no concept of shared data/local WAL. Whereas Oracle
supports threads of REDO/UNDO generated by the local node, all WAL in
PGCluster II has to be coordinated between nodes, which creates a bottleneck
on *all* concurrent workloads.

When I first saw the demonstration of PGCluster II, I was in awe.
Unfortunately, when I reviewed the architecture, I saw that it was too good
to be true. Perhaps it has been rearchitected in private to overcome some
of these issues, but I'm not aware of it. All attempts to talk to Atsushi
about it were met with no response.

--
Jonah H. Harris, Senior DBA
myYearbook.com