Re: Oracle RAC Performance - Two node test provides scaling to 10+nodes?

<xhoster_at_gmail.com> wrote in message
news:20050519125655.964$R1_at_newsreader.com...
> "Jonathan Lewis" <jonathan_at_jlcomp.demon.co.uk> wrote:

>> As Gopalakrishnan points out, the critical limit it three
>> nodes. In fact you get a clue from the 10g wait events
>> which list : '2 way cache fusion' and '3 way cache fusion'
>> and don't go above that.
>>

>
> I'm not sure I buy this argument. It seems to me the worse case
> scenario is more like:
>
> Nodes A, D, J, L, M, O, Q, R, T, U, V, X, and Z all independently
> say to Node B "I want block X".
>
> And then node B says "Node C, give X to A, and the rest of y'all sod off
> for now".
>

This would, indeed, be the effect you could see. I have to admit that I was pre-supposing that the application behaved well at two nodes.

If the scenario you described was going to happen with A-Z nodes, the application would not be scaling at two nodes.

-- 
Regards

Jonathan Lewis

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