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From Ritesh Agrawal <ragra...@netflix.com>
Subject Re: UDAF terminatePartial structure
Date Mon, 29 Jul 2013 23:32:23 GMT
Hi Robin,

Thanks for the suggestion. I did find such an example in Hadoop The definitive guide book.
However I am not total confused. 

The book extends UDAF instead of AbstractGenericUDAFResolver. Which one is recommended ? 

Also the example in the book uses DoubleWritable as a return type for the "terminate" function.
However, I will be returning an arraylist of double. Do I always need to written objects that
are derived from WritableComponents.

Ritesh
On Jul 29, 2013, at 4:15 PM, Robin Morris wrote:

> I believe a map will be passed correctly from the terminatePartial to the
> merge functions.  But it seems a bit of overkill.
> 
> Why not define a class within your UDAF which has 4 public data members,
> and return instances of that class from terminatePartial()?
> 
> Robin
> 
> 
> On 7/29/13 3:19 PM, "Ritesh Agrawal" <ragrawal@netflix.com> wrote:
> 
>> Hi all,
>> 
>> I am writing my first UDAF. In my terminatePartial() function, I need to
>> store different data having different data types. Below is a list of
>> items that I need to store
>> 1. C1 : list of doubles
>> 2. C2: list of doubles
>> 3. C3: double
>> 4. Show: list of strings
>> 
>> 
>> I am wondering can I use simple HashMap and store these different objects
>> into it. Will it automatically serialize or will I need to write my own
>> serializiable method. Also is there any example of a UDAF that shows how
>> to use map type structure for storing partial results.
>> 
>> Thanks
>> 
>> Ritesh
> 


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