Results from a Map/Reduce

[Peter Haidinyak]

Hi, dumb question again.
  I have been using a Scan to return a result back to my client which works 
fine except when I am returning a million rows just to aggregate the results. 
The next logical step would be to do the aggregation in a Map/Reduce. I've been 
looking at what samples I could find and they see to all do this...

    System.exit(job.waitForCompletion(true) ? 0 : 1);

My question, is there a way to return a result from the job in a similar way of 
getting a ResultScanner back in iterating through the results?

Also, is there a good definition of what a 'FirstKeyOnlyFilter' does?

Thanks

-Pete