Re: reads which modify data

can you explain what you mean by manually synching ?

r a f t

On Sun, Mar 1, 2009 at 11:11 PM, Klaus Wuestefeld
<[email protected]> wrote:
> You described the solution yourself:
>
> Make the randomness pseudo-random using a seed. So now you are simply
> doing lazy-eval in your queries, which is ok. You just have to
> manually sync that, of course, which sounds simple to do in your case.
>
> What am I missing?
>
>
>
> On Sun, Mar 1, 2009 at 1:03 PM, Justin T. Sampson <[email protected]> wrote:
>> 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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>>
>>
>>
>> --
>> Agile Focus - http://agilefocus.com/
>>
>> ------------------------------------------------------------------------------
>> Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA
>> -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
>> -Strategies to boost innovation and cut costs with open source participation
>> -Receive a $600 discount off the registration fee with the source code: SFAD
>> http://p.sf.net/sfu/XcvMzF8H
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>> To unsubscribe go to the end of this page:
>> http://lists.sourceforge.net/lists/listinfo/prevayler-discussion
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>>
>
> ------------------------------------------------------------------------------
> Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA
> -OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
> -Strategies to boost innovation and cut costs with open source participation
> -Receive a $600 discount off the registration fee with the source code: SFAD
> http://p.sf.net/sfu/XcvMzF8H
> _______________________________________________
> To unsubscribe go to the end of this page: http://lists.sourceforge.net/lists/listinfo/prevayler-discussion
> _______________________________________________
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------------------------------------------------------------------------------
Open Source Business Conference (OSBC), March 24-25, 2009, San Francisco, CA
-OSBC tackles the biggest issue in open source: Open Sourcing the Enterprise
-Strategies to boost innovation and cut costs with open source participation
-Receive a $600 discount off the registration fee with the source code: SFAD
http://p.sf.net/sfu/XcvMzF8H
_______________________________________________
To unsubscribe go to the end of this page: http://lists.sourceforge.net/lists/listinfo/prevayler-discussion
_______________________________________________
"Databases in Memoriam" -- http://www.prevayler.org