On Sun, Nov 7, 2010 at 5:38 AM, Anthony Urso wrote:
> Is there any way to know how many values I will see in a call to
> reduce without first counting through them all with the iterator?
No, there currently isn't. The framework doesn't have the information until
the iterator is exhausted. The i
It is key to the scheduling paradigm of Hadoop that it doesn't have to
tell you how many or when. It would have to store up all of the data
for your key before activating your reducer. This is exactly what it
cannot do and scale.
(right?)
On Mon, Nov 8, 2010 at 3:32 AM, Niels Basjes wrote:
> Hi,
Hi,
2010/11/7 Anthony Urso
> Is there any way to know how many values I will see in a call to
> reduce without first counting through them all with the iterator?
>
> Under 0.21? 0.20? 0.19?
>
I've looked for an answer to the same question a while ago and came to the
conclusion that you can't.
T
Is there any way to know how many values I will see in a call to
reduce without first counting through them all with the iterator?
Under 0.21? 0.20? 0.19?
Thanks,
Anthony
