最新なHortonworks HDPCD問題集（110題）、真実試験の問題を全部にカバー！

質問 1：
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. Place the data file in the DistributedCache 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. Serialize the data file, insert in it the JobConf object, and read the data into memory in the configure method of the mapper.
正解：C

質問 2：
Which one of the following statements is FALSE regarding the communication between DataNodes and a federation of NameNodes in Hadoop 2.2?
A. Each DataNode registers with all the NameNodes.
B. Each DataNode receives commands from one designated master NameNode.
C. DataNodes send periodic block reports to all the NameNodes.
D. DataNodes send periodic heartbeats to all the NameNodes.
正解：B

質問 3：
In a MapReduce job, you want each of your input files processed by a single map task. How do you configure a MapReduce job so that a single map task processes each input file regardless of how many blocks the input file occupies?
A. Increase the parameter that controls minimum split size in the job configuration.
B. Set the number of mappers equal to the number of input files you want to process.
C. Write a custom FileInputFormat and override the method isSplitable to always return false.
D. Write a custom MapRunner that iterates over all key-value pairs in the entire file.
正解：C
解説: (Pass4Test メンバーにのみ表示されます)

質問 4：
Can you use MapReduce to perform a relational join on two large tables sharing a key? Assume that the two tables are formatted as comma-separated files in HDFS.
A. No, but it can be done with either Pig or Hive.
B. Yes, so long as both tables fit into memory.
C. Yes, but only if one of the tables fits into memory
D. No, MapReduce cannot perform relational operations.
E. Yes.
正解：E
解説: (Pass4Test メンバーにのみ表示されます)

質問 5：
You are developing a combiner that takes as input Text keys, IntWritable values, and emits Text keys, IntWritable values. Which interface should your class implement?
A. Mapper <Text, IntWritable, Text, IntWritable>
B. Combiner <Text, Text, IntWritable, IntWritable>
C. Combiner <Text, IntWritable, Text, IntWritable>
D. Reducer <Text, IntWritable, Text, IntWritable>
E. Reducer <Text, Text, IntWritable, IntWritable>
正解：D