When Is The Reducers Are Started In A Mapreduce Job?

1.	When Is The Reducers Are Started In A Mapreduce Job?
Answer» In a MapReduce job reducers do not START EXECUTING the reduce method until the all Map JOBS have completed. Reducers start COPYING INTERMEDIATE key-value pairs from the mappers as soon as they are available. The programmer defined reduce method is called only after all the mappers have finished. In a MapReduce job reducers do not start executing the reduce method until the all Map jobs have completed. Reducers start copying intermediate key-value pairs from the mappers as soon as they are available. The programmer defined reduce method is called only after all the mappers have finished.

Answer»

In a MapReduce job reducers do not START EXECUTING the reduce method until the all Map JOBS have completed. Reducers start COPYING INTERMEDIATE key-value pairs from the mappers as soon as they are available. The programmer defined reduce method is called only after all the mappers have finished.

In a MapReduce job reducers do not start executing the reduce method until the all Map jobs have completed. Reducers start copying intermediate key-value pairs from the mappers as soon as they are available. The programmer defined reduce method is called only after all the mappers have finished.

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