Re: Documentation for reasons to NOT use RAC?
- From: Martin Bach <development@xxxxxxxxxxxxxxxxx>
- To: Freek.DHooge@xxxxxxxxx
- Date: Wed, 19 May 2010 08:51:06 +0100
Ah, now we're talking!
On 05/19/2010 07:32 AM, D'Hooge Freek wrote:
> Yong,
>
> For an application to realy benifit rac, the developers have to make it aware
> of fan.
FAN and FCF are probably two of the most underused (understood?)
components in RAC. If I were a developer or dev manager I'd ditch _all_
TAF in favour of FCF and middle tier connection pooling with UCP. I
worked on that combination as part of a chapter I composed for workload
management in RAC <shameless plug>Watch out for chapter 11 of "Pro
Oracle Database 11g RAC on Linux" by Dyke/Shaw and me :) </shameless
plug>. I also disagree with the statement that developers don't need to
know RAC-sure, we no longer use block pinging but hey, it's a cluster
and that requires some specific knowledge _about_ clustering and its
specific needs. It's like saying a Formula 1 car is just a car and you
don't need to know about the specifics (tire
temperature/wear/driving/accelerating). For those from the UK see how
Richard Hammond tried driving the Renault F1 car in Top Gear :)
Bottom line-an application not written with scalability and RAC in mind
will most likely not perform well on RAC (nor single instance).
> There are some prerequisites on the java classes to be used and statements
> should be retried when a failover happens.
> To be scalable on rac the application should also be "functional partitioned"
> so different modules of the application can be pointed to different nodes
> (instead of just load balancing everything).
>
Simon Haslam is going to present about this topic in the summer RAC & HA
SIG in London (http://www.ukoug.org/calendar/show_event.jsp?id=4674).
> And last but not least, the application should be performance tested on rac.
> Executing a lot of queries each doing full table scans, makes rac very unhappy
>
> So yes, if you want your application not just to run on rac, but also really
> benefit from it and have good performance, then the developers should develop
> with rac in their minds.
>
> (and not use Hibernate)
Amen! Sorry I get slightly excited sometimes when it comes to this
topic, has to do with the position I am currently working in. Let's
train the developers!
>
[..]
>
>
Strictly my opinion only,
Martin
--
Martin Bach
OCM 10g
http://martincarstenbach.wordpress.com
http://www.linkedin.com/in/martincarstenbach
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