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
