Cloudera CCD-410 Questions Answers

A combiner reduces:

A. The number of values across different keys in the iterator supplied to a single reduce method call.
B. The amount of intermediate data that must be transferred between the mapper and reducer.
C. The number of input files a mapper must process.
D. The number of output files a reducer must produce.

Answer: B

To process input key-value pairs, your mapper needs to lead a 512 MB data file in memory. What is the best way to accomplish this?

A. Serialize the data file, insert in it the JobConf object, and read the data into memory in the configure method of the mapper.
B. Place the data file in the DistributedCache and read the data into memory in the map method of the mapper.
C. Place the data file in the DataCache and read the data into memory in the configure method of the mapper.
D. Place the data file in the DistributedCache and read the data into memory in the configure method of the mapper.

Answer: C