Re: PostgreSQL clustering VS MySQL clustering

Oracle's RAC is good, but I think it's best to view it as a step in the high
availability direction rather than a performance enhancer. While it can help
your application scale up, that depends on the usage pattern. Also it's not
100% transparent to the application for example you can't depend on a
sequence numbers being allocated uniquely as there can be delays propagating
them to all nodes. So in clusters where insert rates are high this means you
should explicitly check for unique key violations and try again. Dealing
with propagation delays comes with the clustering technology I guess.
Nonetheless, I would love to see this kind of functionality in postgres.

Regards
Iain

----- Original Message -----
From: "Jim C. Nasby" <decibel@decibel.org>
To: "Bruno Almeida do Lago" <teolupus@gmail.com>
Cc: "'Mitch Pirtle'" <mitch.pirtle@gmail.com>;
<pgsql-performance@postgresql.org>
Sent: Friday, January 21, 2005 10:30 AM
Subject: Re: [PERFORM] PostgreSQL clustering VS MySQL clustering


> On Thu, Jan 20, 2005 at 10:40:02PM -0200, Bruno Almeida do Lago wrote:
>>
>> I was thinking the same! I'd like to know how other databases such as
>> Oracle
>> do it.
>>
> In a nutshell, in a clustered environment (which iirc in oracle means
> shared disks), they use a set of files for locking and consistency
> across machines. So you better have fast access to the drive array, and
> the array better have caching of some kind.
> --
> Jim C. Nasby, Database Consultant               decibel@decibel.org
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