I would like the values for a key to exist in a single file, and only the values for that key. Each reduced key/value would get its own file. If I understand correctly, all output of the reducers is written to a single file.

-Myles

On Jan 16, 2008, at 9:29 PM, Amar Kamat wrote:

Hi,
Why couldn't you just write this logic in your reducer class. The reduce [reduceClass.reduce()] method is invoked with a key and an iterator over the values associated with the key. You can simply dump the values into a file. Since the input to the reducer is sorted you can simply dump the values to a file i.e no bookkeeping is required. I think this is what you wanted. no?
Myles Grant wrote:
Hello,

I'd like me reduce tasks to each output a single file per key, containing the value. Each file would be named with the key. It appears that I need to (at least) create a new OutputFormat and possible a RecordWriter. As doing this would likely involve a lot of trial and error on my part, I was curious if someone had implemented this already and would like to share. I will be needing both versions that write text files and binary files eventually.

Short a full existing implementation that I can steal, how about some hints?

Cheers,
Myles


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