RE: Educating developers on RAC

From: Paul Harrison <cure_at_austin.rr.com>
Date: Tue, 12 Jun 2012 12:40:16 -0500
Message-ID: <001801cd48c2$6dd9fbb0$498df310$_at_austin.rr.com>

where you can have the same query running on several nodes <-- What do you mean by that exactly?

Thanks

-----Original Message-----
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Guillermo Alan Bort
Sent: Tuesday, June 12, 2012 12:20 PM
To: gabriel.aragon_at_ge.com
Cc: oracle-l_at_freelists.org
Subject: Re: Educating developers on RAC

This is far more complicated than you'd imagine. If developers manage connect strings, then explaining how SCAN work is a must. The difficulty with RAC, in my opinion, lies in the distributed nature of the RAC, where you can have the same query running on several nodes. If that query is a DML, then you may find hot blocks clogging the interconnect. There are also some applications that scale better than others in RAC due to the nature of the application. In havily transactional systems you may find RAC is of very little use. If the hardware is the same, the fastest way to split an app for RAC use is DML versus strictly SELECT queries, leaving DMLs restricted to only one node (or even maybe two). Doing this through services will ensure availability.
Cheers
Alan.-

On Tue, Jun 12, 2012 at 1:13 PM, Aragon, Gabriel (GE, Corporate, consultant) <gabriel.aragon_at_ge.com> wrote:

> (Sending again in plain text)
>
> Hi list,
>
> Well I think the subject speaks for itself, goal is to explain
> developers what should they be expecting when their instances are
> moved to RAC, maybe how the scan works, how rac works, etc , how their
> queries are executed..
>
> Not a RAC training maybe just a quick introducing or features for
> developers doc.. any ideas? Is it any doc already created for this? I
> don't want to invent the wheel.
>
> TIA
> Regards,
> Gabriel
> --
> http://www.freelists.org/webpage/oracle-l
>
>
>

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Received on Tue Jun 12 2012 - 12:40:16 CDT