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From Robin Verlangen <ro...@us2.nl>
Subject Re: are counters stable enough for production?
Date Tue, 18 Sep 2012 15:47:07 GMT
" To go further, would it maybe be an idea to count everything twice? One
as postive value and once as negative value. When reading the counters, the
application could just compare the negative and positive counter to get an
error margin. "

This sounds interesting. Maybe someone should implement this, maybe even
backed with a mysql mirror and compare the results after a week of full
load.

" I assume most people would rather have an under- than an overcount. "

This is probably 100% dependent on your use case. If you're counting errors
on an application that you really bother you would prefer an overcount over
an undercount. If you're counting profit you would not want to measure more
than you actually made. However in all cases you'll want the rights
results: spot on without loss of precision.

Best regards,

Robin Verlangen
*Software engineer*
*
*
W http://www.robinverlangen.nl
E robin@us2.nl

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2012/9/18 horschi <horschi@gmail.com>

> "The repair of taking the highest value of two inconsistent might cause
> getting higher values?"
>
>
> If a counter counts backwards (therefore has negative values), then repair
> would still choose the larger value? Or does cassandra take the highter
> absolute value?  This would result to an undercounting in case of an error
> instead of an overcount.
>
> To go further, would it maybe be an idea to count everything twice? One as
> postive value and once as negative value. When reading the counters, the
> application could just compare the negative and positive counter to get an
> error margin.
>
> Has anybody tried something like this? I assume most people would rather
> have an under- than an overcount.
>
> cheers,
> Christian
>
>
>

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