Explanation:Users can control the grouping by specifying a Comparator via JobConf.setOutputKeyComparatorClass(Class). 5. Point out the wrong statement :
A. The Mapper outputs are sorted and then partitioned per Reducer
B. The total number of partitions is the same as the number of reduce tasks for the job
C. The intermediate, sorted outputs are always stored in a simple (key-len, key, value-len, value) format
D. None of the mentioned
Answer:A
Explanation:Users can control the grouping by specifying a Comparator via JobConf.setOutputKeyComparatorClass(Class). 5. Point out the wrong statement :
A. The Mapper outputs are sorted and then partitioned per Reducer B. The total number of partitions is the same as the number of reduce tasks for the job C. The intermediate, sorted outputs are always stored in a simple (key-len, key, value-len, value) format D. None of the mentioned
Explanation:All intermediate values associated with a given output key are subsequently grouped by the framework, and passed to the Reducer(s) to determine the final output. 6. Applications can use the ____________ to report progress and set application-level status messages