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Re: Instance IDs and models in the ORM world


On Fri, Oct 8, 2010 at 5:03 AM, Soren Hansen <soren@xxxxxxxxxx> wrote:

> > We want to support 1 million instances, right?  Which is 1/4000 the
> > keyspace, so we have something like a 1 in 4000 chance of a
> > collision once we hit a million instances.
> Mm... Not exactly. 1/4000 is the chance of collision for the last one,
> assuming an even distribution.
> You reach a 1/4000 chance of having had *a* collision before you
> even start 150 instances. After a million instances, that figure grows
> to 99.99999999999999999999999999999999999999999999999999% or
> thereabouts. We're in 99% territory after a measly 200,000 instances.

Thank you!  Just the statistics that I needed :)

pvo already pointed out that I'm an idiot, and we're not trying to support
1MM virtual instances, we're targeting 1MM physical hosts.  So next week
I'll be making this 64 bits for Austin, and as Ewan said, next month we can
discuss what we want to do for Bexar.


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