Hortonworks HDP Certified Developer HDPCD Questions & Answers

• Question 101:

  Consider the following two relations, A and B.

  

  A Pig JOIN statement that combined relations A by its first field and B by its second field would produce what output?

  A. 2 Jim Chris 2 3 Terry 3 4 Brian 4

  B. 2 cherry 2 cherry 3 orange 4 peach

  C. 2 cherry Jim, Chris 3 orange Terry 4 peach Brian

  D. 2 cherry Jim 2 2 cherry Chris 2 3 orange Terry 3 4 peach Brian 4

  Correct Answer: D

• Question 102:

  To use a lava user-defined function (UDF) with Pig what must you do?

  A. Define an alias to shorten the function name

  B. Pass arguments to the constructor of UDFs implementation class

  C. Register the JAR file containing the UDF

  D. Put the JAR file into the userandapos;s home folder in HDFS

  Correct Answer: C

• Question 103:

  You want to understand more about how users browse your public website, such as which pages they visit prior to placing an order. You have a farm of 200 web servers hosting your website. How will you gather this data for your analysis?

  A. Ingest the server web logs into HDFS using Flume.

  B. Write a MapReduce job, with the web servers for mappers, and the Hadoop cluster nodes for reduces.

  C. Import all users' clicks from your OLTP databases into Hadoop, using Sqoop.

  D. Channel these clickstreams inot Hadoop using Hadoop Streaming.

  E. Sample the weblogs from the web servers, copying them into Hadoop using curl.

  Correct Answer: A

• Question 104:

  Which one of the following files is required in every Oozie Workflow application?

  A. job.properties

  B. Config-default.xml

  C. Workflow.xml

  D. Oozie.xml

  Correct Answer: C

• Question 105:

  You've written a MapReduce job that will process 500 million input records and generated 500 million key-value pairs. The data is not uniformly distributed. Your MapReduce job will create a significant amount of intermediate data that it needs to transfer between mappers and reduces which is a potential bottleneck. A custom implementation of which interface is most likely to reduce the amount of intermediate data transferred across the network?

  A. Partitioner

  B. OutputFormat

  C. WritableComparable

  D. Writable

  E. InputFormat

  F. Combiner

  Correct Answer: F

  Explanation: Combiners are used to increase the efficiency of a MapReduce program. They are used to aggregate intermediate map output locally on individual mapper outputs. Combiners can help you reduce the amount of data that needs to be transferred across to the reducers. You can use your reducer code as a combiner if the operation performed is commutative and associative.

  Reference: 24 Interview Questions and Answers for Hadoop MapReduce developers, What are combiners? When should I use a combiner in my MapReduce Job?

• Question 106:

  A combiner reduces:

  A. The number of values across different keys in the iterator supplied to a single reduce method call.

  B. The amount of intermediate data that must be transferred between the mapper and reducer.

  C. The number of input files a mapper must process.

  D. The number of output files a reducer must produce.

  Correct Answer: B

  Explanation: Combiners are used to increase the efficiency of a MapReduce program. They are used to aggregate intermediate map output locally on individual mapper outputs. Combiners can help you reduce the amount of data that needs to be transferred across to the reducers. You can use your reducer code as a combiner if the operation performed is commutative and associative. The execution of combiner is not guaranteed, Hadoop may or may not execute a combiner. Also, if required it may execute it more then 1 times. Therefore your MapReduce jobs should not depend on the combiners execution.

  Reference: 24 Interview Questions and Answers for Hadoop MapReduce developers, What are combiners? When should I use a combiner in my MapReduce Job?

• Question 107:

  Examine the following Hive statements:

  

  Assuming the statements above execute successfully, which one of the following statements is true?

  A. Hive reformats File1 into a structure that Hive can access and moves into to/user/joe/x/

  B. The file named File1 is moved to to/user/joe/x/

  C. The contents of File1 are parsed as comma-delimited rows and loaded into /user/joe/x/

  D. The contents of File1 are parsed as comma-delimited rows and stored in a database

  Correct Answer: B

• Question 108:

  In Hadoop 2.2, which one of the following statements is true about a standby NameNode?

  The Standby NameNode:

  A. Communicates directly with the active NameNode to maintain the state of the active NameNode.

  B. Receives the same block reports as the active NameNode.

  C. Runs on the same machine and shares the memory of the active NameNode.

  D. Processes all client requests and block reports from the appropriate DataNodes.

  Correct Answer: B