Re: reads which modify data

To take your example literally, why wouldn't you apply the random damage
during the write operation, at the moment the velocity drops to zero?

-Justin


On Sun, Mar 1, 2009 at 5:48 AM, hakan eryargi <[email protected]>wrote:

> hello,
>
> how would you design a system where some reads modify the data in an
> undeterministic way ? undeterministic means random here and can be
> translated into a deterministic one by supplying random seed from
> outside.
>
> one can say, these are actually writes not reads, so must be handled
> as transactions. the answer is there are so many of them so we cannot
> simply afford handling them as transactions. and a very very little
> proportion of that reads cause such random modifications.
>
> these reads trigger lazy calculations as described in this thread:
>
> http://www.nabble.com/Re%3A-execution-order-of-queries-and-transactions-p17049169.html
>
> continuing the sample in that thread: think of a moving entity. a
> write operation modifies its acceleration and direction, read
> operation calculates current velocity and position and returns them.
> no matter how many times you read the velocity, it will be the same at
> some specific point in time.  it's ok till now. now add another
> feature that when entity's velocity drops to zero it takes some random
> damage. so when velocity or position is read, there is a chance that
> this will trigger a damage.
>
> how would you persist such a system with prevayler ?
>
> regards,
> r a f t
>
>
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-OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
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