Apache-Hadoop-Developer無料問題集「Hortonworks Hadoop 2.0 Certification exam for Pig and Hive Developer」

質問 1

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）3

（B）5

（C）1

（D）6

（E）0

正解：A 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 2

Which one of the following statements describes a Pig bag. tuple, and map, respectively?

（A）Ordered set of fields, ordered collection of tuples, ordered collection of maps

（B）Unordered collection of maps, ordered collection of tuples, ordered set of key/value pairs

（C）Unordered collection of tuples, ordered set of fields, set of key value pairs

（D）Ordered collection of maps, ordered collection of bags, and unordered set of key/value pairs

正解：C 解答を投票する

質問 3

What is the disadvantage of using multiple reducers with the default HashPartitioner and distributing your workload across you cluster?

（A）You will longer be able to take advantage of a Combiner.

（B）You will not be able to compress the intermediate data.

（C）By using multiple reducers with the default HashPartitioner, output files may not be in globally sorted order.

（D）There are no concerns with this approach. It is always advisable to use multiple reduces.

正解：C 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 4

You use the hadoop fs -put command to write a 300 MB file using and HDFS block size of 64 MB. Just after this command has finished writing 200 MB of this file, what would another user see when trying to access this life?

（A）They would see the current of the file through the last completed block.

（B）They would see no content until the whole file written and closed.

（C）They would see Hadoop throw an ConcurrentFileAccessException when they try to access this file.

（D）They would see the current state of the file, up to the last bit written by the command.

正解：A 解答を投票する

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 seventeen failed task attempts

（B）You will have twelve failed task attempts

（C）You will have forty-eight failed task attempts

（D）You will have five failed task attempts

（E）You will have twenty failed task attempts

正解：E 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 6

Indentify the utility that allows you to create and run MapReduce jobs with any executable
or script as the mapper and/or the reducer?

（A）Flume

（B）Hadoop Streaming

（C）Oozie

（D）mapred

（E）Sqoop

正解：B 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 7

You want to count the number of occurrences for each unique word in the supplied input data. You've decided to implement this by having your mapper tokenize each word and emit a literal value 1, and then have your reducer increment a counter for each literal 1 it
receives. After successful implementing this, it occurs to you that you could optimize this by specifying a combiner. Will you be able to reuse your existing Reduces as your combiner in this case and why or why not?

（A）No, because the Reducer and Combiner are separate interfaces.

（B）No, because the sum operation in the reducer is incompatible with the operation of a Combiner.

（C）No, because the Combiner is incompatible with a mapper which doesn't use the same data type for both the key and value.

（D）Yes, because Java is a polymorphic object-oriented language and thus reducer code can be reused as a combiner.

（E）Yes, because the sum operation is both associative and commutative and the input and output types to the reduce method match.

正解：E 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 8

Given a directory of files with the following structure: line number, tab character, string:
Example:
1abialkjfjkaoasdfjksdlkjhqweroij
2kadfjhuwqounahagtnbvaswslmnbfgy
3kjfteiomndscxeqalkzhtopedkfsikj
You want to send each line as one record to your Mapper. Which InputFormat should you use to complete the line: conf.setInputFormat (____.class) ; ?

（A）KeyValueFileInputFormat

（B）SequenceFileAsTextInputFormat

（C）SequenceFileInputFormat

（D）BDBInputFormat

正解：A 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 9

Determine which best describes when the reduce method is first called in a MapReduce job?

（A）Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The reduce method is called only after all intermediate data has been copied and sorted.

（B）Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The programmer can configure in the job what percentage of the intermediate data should arrive before the reduce method begins.

（C）Reducers start copying intermediate key-value pairs from each Mapper as soon as it has completed. The reduce method is called as soon as the intermediate key-value pairs start to arrive.

（D）Reduce methods and map methods all start at the beginning of a job, in order to provide optimal performance for map-only or reduce-only jobs.

正解：A 解答を投票する

解説: (JPNTest メンバーにのみ表示されます)

質問 10

What is the term for the process of moving map outputs to the reducers?

（A）Combining

（B）Shuffling and sorting

（C）Reducing

（D）Partitioning

正解：B 解答を投票する

Apache-Hadoop-Developer 無料問題集「Hortonworks Hadoop 2.0 Certification exam for Pig and Hive Developer」

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