-Re: UDAF terminatePartial structure
Igor Tatarinov 2013-07-29, 23:37
I found this Cloudera example helpful:
On Mon, Jul 29, 2013 at 4:32 PM, Ritesh Agrawal <[EMAIL PROTECTED]>wrote:
> 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
> 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" <[EMAIL PROTECTED]> 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
> >> 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