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From: Bruce Momjian <bruce@momjian.us>
Message-Id: <200611142204.kAEM4Ba27328@momjian.us>
Subject: Re: [HACKERS] Replication documentation addition
In-Reply-To: 
 <Pine.LNX.4.64.0611141401000.23695@discord.home.frostconsultingllc.com>
To: Jeff Frost <jeff@frostconsultingllc.com>
Date: Tue, 14 Nov 2006 17:04:11 -0500 (EST)
CC: Chris Browne <cbbrowne@acm.org>, pgsql-docs@postgresql.org
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Jeff Frost wrote:
> On Tue, 14 Nov 2006, Bruce Momjian wrote:
> 
> > Your description was too detailed, but I took some of your concepts:
> >
> >  <para>
> >   In clustering, each server can accept write requests, and these
> >   write requests are broadcast from the original server to all
> >   other servers before each transaction commits.  Heavy write
> >   activity can cause excessive locking, leading to poor performance.
> >   In fact, write performance is often worse than that of a single
> >   server.  Read requests can be sent to any server.  Clustering
> >   is best for mostly read workloads, though its big advantage is
> >   that any server can accept write requests --- there is no need
> >   to partition workloads between read/write and read-only servers.
> >  </para>
> >
> >  <para>
> >   Clustering is implemented by <productname>Oracle</> in their
> >   <productname><acronym>RAC</></> product.  <productname>PostgreSQL</>
> >   does not offer this type of load balancing, though
> >   <productname>PostgreSQL</> two-phase commit (<xref
> >   linkend="sql-prepare-transaction-title"> and <xref linkend=
> >   "sql-commit-prepared-title">) can be used to implement this in
> >   application code or middleware.
> >  </para>
> 
> Bruce,
> 
> Continuent's uni/cluster middleware product implements this type of 
> clustering/load balancing.  Perhaps it warrants a mention?  Not sure how far 
> we want to get into listing external products.

We had a long discussion about that and felt that recommending
commercial products or even every open source project was too much.  The
idea was that we should reference a web page that has them all mentioned,
but no one has set one up yet.

-- 
  Bruce Momjian   bruce@momjian.us
  EnterpriseDB    http://www.enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +