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Date: Tue, 14 Nov 2006 14:18:20 -0800 (PST)
From: Jeff Frost <jeff@frostconsultingllc.com>
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To: Bruce Momjian <bruce@momjian.us>
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On Tue, 14 Nov 2006, Bruce Momjian wrote:

> 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.

That makes sense, I just hate to see us say something like "Oracle can do 
this with RAC but PostgreSQL cannot."

-- 
Jeff Frost, Owner 	<jeff@frostconsultingllc.com>
Frost Consulting, LLC 	http://www.frostconsultingllc.com/
Phone: 650-780-7908	FAX: 650-649-1954