APACHE-HADOOP-DEVELOPER Online Practice Questions and Answers

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. SequenceFileAsTextInputFormat

B. SequenceFileInputFormat

C. KeyValueFileInputFormat

D. BDBInputFormat

You have just executed a MapReduce job. Where is intermediate data written to after being emitted from the Mapper's map method?

A. Intermediate data in streamed across the network from Mapper to the Reduce and is never written to disk.

B. Into in-memory buffers on the TaskTracker node running the Mapper that spill over and are written into HDFS.

C. Into in-memory buffers that spill over to the local file system of the TaskTracker node running the Mapper.

D. Into in-memory buffers that spill over to the local file system (outside HDFS) of the TaskTracker node running the Reducer

E. Into in-memory buffers on the TaskTracker node running the Reducer that spill over and are written into HDFS.

Which Hadoop component is responsible for managing the distributed file system metadata?

A. NameNode

B. Metanode

C. DataNode

D. NameSpaceManager

Which best describes how TextInputFormat processes input files and line breaks?

A. Input file splits may cross line breaks. A line that crosses file splits is read by the RecordReader of the split that contains the beginning of the broken line.

B. Input file splits may cross line breaks. A line that crosses file splits is read by the RecordReaders of both splits containing the broken line.

C. The input file is split exactly at the line breaks, so each RecordReader will read a series of complete lines.

D. Input file splits may cross line breaks. A line that crosses file splits is ignored.

E. Input file splits may cross line breaks. A line that crosses file splits is read by the RecordReader of the split that contains the end of the broken line.

In Hadoop 2.0, which TWO of the following processes work together to provide automatic failover of the NameNode? Choose 2 answers

A. ZKFailoverController

B. ZooKeeper

C. QuorumManager

D. JournalNode

Examine the following Pig commands:

Which one of the following statements is true?

A. The SAMPLE command generates an "unexpected symbol" error

B. Each MapReduce task will terminate after executing for 0.2 minutes

C. The reducers will only output the first 20% of the data passed from the mappers

D. A random sample of approximately 20% of the data will be output

MapReduce v2 (MRv2/YARN) splits which major functions of the JobTracker into separate daemons? Select two.

A. Heath states checks (heartbeats)

B. Resource management

C. Job scheduling/monitoring

D. Job coordination between the ResourceManager and NodeManager

E. Launching tasks

F. Managing file system metadata

G. MapReduce metric reporting H. Managing tasks

Consider the following two relations, A and B.

What is the output of the following Pig commands?

X = GROUP A BY S1;

DUMP X;

A. Option A

B. Option B

C. Option C

D. Option D

Assuming the following Hive query executes successfully:

Which one of the following statements describes the result set?

A. A bigram of the top 80 sentences that contain the substring "you are" in the lines column of the input data A1 table.

B. An 80-value ngram of sentences that contain the words "you" or "are" in the lines column of the inputdata table.

C. A trigram of the top 80 sentences that contain "you are" followed by a null space in the lines column of the inputdata table.

D. A frequency distribution of the top 80 words that follow the subsequence "you are" in the lines column of the inputdata table.

When is the earliest point at which the reduce method of a given Reducer can be called?

A. As soon as at least one mapper has finished processing its input split.

B. As soon as a mapper has emitted at least one record.

C. Not until all mappers have finished processing all records.

D. It depends on the InputFormat used for the job.