Hey guys,
patch is attached + tested on unit-tests + We're testing it on a 1000-nodes real hadoop cluster as we speak. 
Do you want us to create a jira issue for this, or is this good enough?
Thanks, Ilia and Ido

On 7 March 2015 at 23:09, Matthew Hayes <matthew.terence.hayes@gmail.com> wrote:
I don't remember if there was a particular reason I didn't implement this as AlgebraicEvalFunc. It seems like it could be. I believe the Java MapReduce version leverages the combiner. If you want to try making this Algebraic we would be happy to accept a patch :)

-Matt

> On Mar 7, 2015, at 12:11 PM, Ido Hadanny <ido.hadanny@gmail.com> wrote:
>
> data.fu has a nice implementation of HyperLogLog for estimating cardinality
> here
> <https://github.com/apache/incubator-datafu/blob/master/datafu-pig/src/main/java/datafu/pig/stats/HyperLogLogPlusPlus.java>
>
> However, it's implemented as Accumulator which means it will run only at
> the reducer and not in the combiner (but it will never load the entire set
> into memory as in normal EvalFunc). Why couldn't data.fu implement it as
> Algebraic - and fill the registers at every combiner, then merge and reduce
> the result? Am I missing something here?
> also available here:
> http://stackoverflow.com/questions/28908217/why-is-data-fu-implementing-hyperloglog-as-an-accumulator-and-not-as-algebraic
>
> thanks!
>
>
> --
> Sent from my androido



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