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From David Boxenhorn <da...@citypath.com>
Subject Re: CounterColumn as a double
Date Tue, 28 Jun 2011 08:10:05 GMT
How about BigDoubles and BigIntegers?

On Tue, Jun 28, 2011 at 3:16 AM, Jonathan Ellis <jbellis@gmail.com> wrote:
> I don't think you can avoid that.
>
> I'd suggest making it CQL-only if we do doubles -- no backwards
> incompatibility required there.
>
> On Mon, Jun 27, 2011 at 7:07 PM, Jason <jfager@gmail.com> wrote:
>> Sorry, I should have been more clear; I was speaking to the question of how to avoid
modifying the thrift interface.
>>
>> - Jason
>>
>> On Jun 27, 2011, at 7:58 PM, Joseph Stein <cryptcom@gmail.com> wrote:
>>
>>> hmmm, well Jason it is not as accurate as I would have thought at first and
>>> the increments on the long are whacked (which now that I think about it more
>>> makes sense since a +1 of the bits as long for the double would not
>>> necessarly represent the +1 on the double).
>>>
>>> So I am setting the increment to be
>>>
>>> 1.23
>>>
>>> which comes back as 1.3213044541238036E308
>>>
>>> and then another increment of 1.23 comes back as 10.359999999999987
>>>
>>> so for the increment (which is just +value to the long which would not
>>> provide the right shift)
>>>
>>> even if under the hood I keep the thrift interface as long somehow the 1.23
>>> vs 1.321 is a big difference when you have billions of them
>>>
>>> so I think it goes back to my original idea/proposition.   Any one have
>>> issue?  any +1 ?  should I create a JIRA and get to it?
>>>
>>> On Mon, Jun 27, 2011 at 7:39 PM, Joseph Stein <cryptcom@gmail.com> wrote:
>>>
>>>> I will give that a shot, seems that it will work fantastically, thanks!
>>>>
>>>> I will keep trolling JIRA then for something I feel I can get my feet wet
>>>> with and contribute then.
>>>>
>>>> On Mon, Jun 27, 2011 at 7:33 PM, Jason Fager <jfager@gmail.com> wrote:
>>>>
>>>>> Longs and Doubles are both 64-bit values and are pretty easily
>>>>> convertible.  Check out Double.doubleToLongBits and
>>>>> Double.longBitsToDouble in the JDK; you can also read more about the
>>>>> details of the conversion and get some pointers to some code in a post
>>>>> I wrote last year:
>>>>> http://jasonfager.com/770-lexi-sortable-number-strings/  (the emphasis
>>>>> is on using doubles in key strings, but it should cover what you
>>>>> need).
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Mon, Jun 27, 2011 at 7:13 PM, Joseph Stein <cryptcom@gmail.com>
wrote:
>>>>>> So has anyone considered using the CounterColumn for summing?
>>>>>>
>>>>>> I wanted to-do this over the weekend until I realized it was only
a long
>>>>> :(
>>>>>> so using it for things like duration (as an example for me this would
>>>>> have
>>>>>> been great to keep track of aggregate durations of ad impressions)
are
>>>>> not
>>>>>> possible (or total costs when processing business workflows, etc,etc).
>>>>>>
>>>>>> I thought this might be a little more the speed of a first contribution
>>>>> too
>>>>>> :) and also helps out with more functionality since a lot of real
time
>>>>>> analytics will need double.
>>>>>>
>>>>>> Let me know, I think it is a good feature.
>>>>>>
>>>>>> Implementing it not sure we would want to break the thrift interface
I
>>>>> would
>>>>>> suggest that I would create another interface for the double value?
>>>>>>
>>>>>> Under the hood of the thrift interface I was thinking of creating
a
>>>>>> CounterValue class and then setting the lValue or the dValue depending
>>>>> on
>>>>>> which thrift function was called. I can update the thrift, add a
sister
>>>>>> function and re-work the entire code path of long CounterColumn.value
>>>>> into
>>>>>> CounterValue CounterColumn.value.
>>>>>>
>>>>>> /*
>>>>>> Joe Stein
>>>>>> http://www.linkedin.com/in/charmalloc
>>>>>> Twitter: @allthingshadoop <http://www.twitter.com/allthingshadoop>
>>>>>> */
>>>>>>
>>>>>
>>>>
>>>>
>>>>
>>>> --
>>>>
>>>> /*
>>>> Joe Stein
>>>> http://www.linkedin.com/in/charmalloc
>>>> Twitter: @allthingshadoop <http://www.twitter.com/allthingshadoop>
>>>> */
>>>>
>>>
>>>
>>>
>>> --
>>>
>>> /*
>>> Joe Stein
>>> http://www.linkedin.com/in/charmalloc
>>> Twitter: @allthingshadoop <http://www.twitter.com/allthingshadoop>
>>> */
>>
>
>
>
> --
> Jonathan Ellis
> Project Chair, Apache Cassandra
> co-founder of DataStax, the source for professional Cassandra support
> http://www.datastax.com
>

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