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. +