In a large MapReduce job with m mappers and n reducers, how many distinct copy operations will there be in the sort/shuffle phase?

• A. m
• B. mXn (i.e., m multiplied by n)
• C. mn (i.e., m to the power of n)
• D. m+n (i.e., m plus n)
• E. n

Which one of the following statements is true about a Hive-managed table?

• A. Hive dynamically defines the schema of the table based on the FROM clause of a SELECT query.
• B. Hive dynamically defines the schema of the table based on the format of the underlying data.
• C. Records can only be added to the table using the Hive INSERT command.
• D. When the table is dropped, the underlying folder in HDFS is deleted.

When can a reduce class also serve as a combiner without affecting the output of a MapReduce program?

• A. Always. Code can be reused in Java since it is a polymorphic object-oriented programming language.
• B. When the types of the reduce operation's input key and input value match the types of the reducer's output key and output value and when the reduce operation is both communicative and associative.
• C. Never. Combiners and reducers must be implemented separately because they serve different purposes.
• D. When the signature of the reduce method matches the signature of the combine method.
• E. Always. The point of a combiner is to serve as a mini-reducer directly after the map phase to increase performance.

You have just executed a MapReduce job.
Where is intermediate data written to after being emitted from the Mapper's map method?

• A. Into in-memory buffers that spill over to the local file system (outside HDFS) of the TaskTracker node running the Reducer
• B. Into in-memory buffers on the TaskTracker node running the Mapper that spill over and are written into HDFS.
• C. Into in-memory buffers on the TaskTracker node running the Reducer that spill over and are written into HDFS.
• D. Intermediate data in streamed across the network from Mapper to the Reduce and is never written to disk.
• E. Into in-memory buffers that spill over to the local file system of the TaskTracker node running the Mapper.

Examine the following Hive statements:

Assuming the statements above execute successfully, which one of the following statements is true?

• A. The contents of File1 are parsed as comma-delimited rows and loaded into /user/joe/x/
• B. The file named File1 is moved to to/user/joe/x/
• C. Hive reformats File1 into a structure that Hive can access and moves into to/user/joe/x/
• D. The contents of File1 are parsed as comma-delimited rows and stored in a database