Hortonworks HADOOP-PR000007 問題集

質問 1：
You need to create a job that does frequency analysis on input data. You will do this by writing a Mapper
that uses TextInputFormat and splits each value (a line of text from an input file) into individual characters.
For each one of these characters, you will emit the character as a key and an InputWritable as the value.
As this will produce proportionally more intermediate data than input data, which two resources should
you expect to be bottlenecks?
A. Processor and disk I/O
B. Disk I/O and network I/O
C. Processor and RAM
D. Processor and network I/O
正解：B

質問 2：
Which one of the following statements describes the relationship between the ResourceManager and the
ApplicationMaster?
A. The ApplicationMaster requests resources from the ResourceManager
B. The ResourceManager monitors and restarts any failed Containers of the ApplicationMaster
C. The ApplicationMaster starts an instance of the ResourceManager within each Container
D. The ApplicationMaster starts a single instance of the ResourceManager
正解：A

質問 3：
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 4：
You want to populate an associative array in order to perform a map-side join. You've decided to put this
information in a text file, place that file into the DistributedCache and read it in your Mapper before any
records are processed. Indentify which method in the Mapper you should use to implement code for
reading the file and populating the associative array?
A. configure
B. combine
C. map
D. init
正解：A

質問 5：
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 DataCache and read the data into memory in the configure method of the
mapper.
C. Serialize the data file, insert in it the JobConf object, 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 map method of the
mapper.
正解：B

質問 6：
Consider the following two relations, A and B.

Which Pig statement combines A by its first field and B by its second field?
A. C = JOIN A by al, B by b2;
B. C = DOIN B BY a1, A by b2;
C. C = JOIN A a1, B b2;
D. C = JOIN A SO, B $1;
正解：A

質問 7：
The Hadoop framework provides a mechanism for coping with machine issues such as faulty
configuration or impending hardware failure. MapReduce detects that one or a number of machines are
performing poorly and starts more copies of a map or reduce task. All the tasks run simultaneously and
the task finish first are used. This is called:
A. Default Partitioner
B. Speculative Execution
C. Combine
D. IdentityMapper
E. IdentityReducer
正解：B