CODEWITHSUNDEEP
javahadoopmapreduce
daydreamer
daydreamer

Reputation: 92139

hadoop : 1 map multiple reducers with each reducer having different functionality? possible?

Here is an example:

Is it possible to have same mapper run against multiple reducers at the same time? like 

map output : {1:[1,2,3,4,5,4,3,2], 4:[5,4,6,7,8,9,5,3,3,2], 3:[1,5,4,3,5,6,7,8,9,1], so on}  

reducer1 : sum of all numbers  
reducer2 : average of all numbers  
reducer3 : mode of all numbers   

act on the the same key like  

reducer1 output: {1:sum of values, 2:sum of values, and so on}  
reducer2 output: {1:avg of values, 2: avg of values and so on}
reducer3 output: {1:mode of values, 2: mode of values, and so on}

and so on..Please let me know.

Upvotes: 3

Views: 12942

Answers (3)

thuang513
thuang513

Reputation: 39

http://www.cloudera.com/blog/2011/04/simple-moving-average-secondary-sort-and-mapreduce-part-3/

This actually does pretty much what you are looking for.

Upvotes: -1

Thomas Jungblut
Thomas Jungblut

Reputation: 20969

No it is not possible. But you can implement your own reducer that will calculate all the stuff for you and output it.

You can make an custom writable for that.

Upvotes: 1

Andrew T Finnell
Andrew T Finnell

Reputation: 13638

I really wanted to answer this for you but it's already been asked. Hadoop one Map and multiple Reduce

Upvotes: 2

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