Hortonworks HDPCD 問題集

質問 1：
Which HDFS command displays the contents of the file x in the user's HDFS home directory?
A. hadoop fs -cat x
B. hadoop fs -cp x
C. hadoop fs -Is x
D. hdfs fs -get x
正解：A

質問 2：
How are keys and values presented and passed to the reducers during a standard sort and shuffle phase of MapReduce?
A. Keys are presented to reducer in sorted order; values for a given key are not sorted.
B. Keys are presented to reducer in sorted order; values for a given key are sorted in ascending order.
C. Keys are presented to a reducer in random order; values for a given key are not sorted.
D. Keys are presented to a reducer in random order; values for a given key are sorted in ascending order.
正解：A
解説: (Topexam メンバーにのみ表示されます)

質問 3：
In a MapReduce job with 500 map tasks, how many map task attempts will there be?
A. Between 500 and 1000.
B. It depends on the number of reduces in the job.
C. At most 500.
D. Exactly 500.
E. At least 500.
正解：E
解説: (Topexam メンバーにのみ表示されます)

質問 4：
Given the following Pig command:
logevents = LOAD 'input/my.log' AS (date:chararray, levehstring, code:int, message:string);
Which one of the following statements is true?
A. The logevents relation represents the data from the my.log file, using a tab as the parsing delimiter
B. The statement is not a valid Pig command
C. The first field of logevents must be a properly-formatted date string or table return an error
D. The logevents relation represents the data from the my.log file, using a comma as the parsing delimiter
正解：A

質問 5：
You wrote a map function that throws a runtime exception when it encounters a control character in input data. The input supplied to your mapper contains twelve such characters totals, spread across five file splits. The first four file splits each have two control characters and the last split has four control characters.
Indentify the number of failed task attempts you can expect when you run the job with mapred.max.map.attempts set to 4:
A. You will have twelve failed task attempts
B. You will have twenty failed task attempts
C. You will have five failed task attempts
D. You will have forty-eight failed task attempts
E. You will have seventeen failed task attempts
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 6：
You have written a Mapper which invokes the following five calls to the OutputColletor.collect method:
output.collect (new Text ("Apple"), new Text ("Red") ) ; output.collect (new Text ("Banana"), new Text ("Yellow") ) ; output.collect (new Text ("Apple"), new Text ("Yellow") ) ; output.collect (new Text ("Cherry"), new Text ("Red") ) ; output.collect (new Text ("Apple"), new Text ("Green") ) ; How many times will the Reducer's reduce method be invoked?
A. 0
B. 3
C. 6
D. 1
E. 5
正解：B
解説: (Topexam メンバーにのみ表示されます)

質問 7：
Which one of the following statements is false about HCatalog?
A. Stores HDFS data in a database for performing SQL-like ad-hoc queries
B. Exists as a subproject of Hive
C. Designed to be used by other programs such as Pig, Hive and MapReduce
D. Provides a shared schema mechanism
正解：A

質問 8：
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