Can sb help please? I would expect there must be some easy way to do that.
Some corrections,
In reducer I do context.getCounter(Counters.INPUT_WORDS).getValue();
But it does not work. it always returns 0.
tigertail wrote:
>
> Hi Hadoop/MapReduce experts,
>
> My question might be naive, But I am really stuck here and I am looking
> forward to get helps/advises from you.
>
> I have an input file like
> key1, 2
> key2, 1
> key1, 1
> key3, 1
>
> It is easy to write a M/R code to calculate the count for each key and
> output sth like
> key1, 3
> key2, 1
> key3, 1
>
> But, how I can calculate the percentage of each key over all keys, with
> the above input, I would expect to get the output as
> key1, 0.60
> key2, 0.20
> key3, 0.20
>
> One naive method is to calculate the total count (5 with the above input)
> which is saved in a file. Then the file is read in before M/R starts. But
> it is obviously ugly and slow.
>
> I also tried to set a static enum Counters { INPUT_WORDS }
> In mapper I do context.getCounter(Counters.INPUT_WORDS).increment(1);
> In reducer I do context.getCounter(Counters.INPUT_WORDS).getValue();
> But it does not work. it always returns 0.
>
> Is there more elegant way?
>
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