Hortonworks Apache-Hadoop-Developer 問題集

質問 1：
In a MapReduce job, the reducer receives all values associated with same key. Which statement best describes the ordering of these values?
A. The values are arbitrarily ordered, and the ordering may vary from run to run of the same MapReduce job.
B. The values are arbitrary ordered, but multiple runs of the same MapReduce job will always have the same ordering.
C. Since the values come from mapper outputs, the reducers will receive contiguous sections of sorted values.
D. The values are in sorted order.
正解：A
解説: (Topexam メンバーにのみ表示されます)

質問 2：
In Hadoop 2.0, which one of the following statements is true about a standby NameNode?
The Standby NameNode:
A. Runs on the same machine and shares the memory of the active NameNode.
B. Communicates directly with the active NameNode to maintain the state of the active NameNode.
C. Processes all client requests and block reports from the appropriate DataNodes.
D. Receives the same block reports as the active NameNode.
正解：D

質問 3：
What is the term for the process of moving map outputs to the reducers?
A. Reducing
B. Combining
C. Shuffling and sorting
D. Partitioning
正解：C

質問 4：
Given the following Pig commands:

Which one of the following statements is true?
A. The $1 variable represents the second column of data in 'my.log'
B. The grouped relation is not valid
C. The severe relation is not valid
D. The $1 variable represents the first column of data in 'my.log'
正解：A

質問 5：
Which TWO of the following statements are true regarding Hive? Choose 2 answers
A. Is a relational database
B. Offers real-time queries and row level updates
C. Useful for data analysts familiar with SQL who need to do ad-hoc queries
D. Allows you to define a structure for your unstructured Big Data
正解：C,D

質問 6：
Which Two of the following statements are true about hdfs? Choose 2 answers
A. Block sizes for all files must be the same size
B. HDFS works best when storing a large number of relatively small files
C. An HDFS file that is larger than dfs.block.size is split into blocks
D. Blocks are replicated to multiple datanodes
正解：C,D

質問 7：
You've written a MapReduce job that will process 500 million input records and generated 500 million key-value pairs. The data is not uniformly distributed. Your MapReduce job will create a significant amount of intermediate data that it needs to transfer between mappers and reduces which is a potential bottleneck. A custom implementation of which interface is most likely to reduce the amount of intermediate data transferred across the network?
A. Partitioner
B. Combiner
C. WritableComparable
D. Writable
E. InputFormat
F. OutputFormat
正解：B
解説: (Topexam メンバーにのみ表示されます)