Mapr (HP) Hadoop Developer Certification Questions and Answers (Dumps and Practice Questions)

Question : No reducers can start until all the mappers have finished ?

1. True
2. False

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Explanation: The reduce() method in the Reducers cannot start until all the Mappers have finished.

In practice, Hadoop will start transfer data from Mappers to Reducers as the Mappers finish work.

The developer can specify the percentage of Mappers which should finish before Reducers start

retrieving data.

The developers reduce method until does not start untill all intermediate data has been transferred and sorted.

Refer HadoopExam.com Recorded Training Module : 3 and 4

Question :Hadoop daemon can share the JVM

1. True
2. False

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Explanation: Each daemon runs in its own Java Virtual Machine.

Refer HadoopExam.com Recorded Training Module : 2 and 3

Question : The cluster block size is set to MB. The input file contains MB of valid input data
and is loaded into HDFS with the default block size. How many map tasks will be run during the execution of this job?

1. 1
2. 2
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4. 4

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Explanation: The job has an implicit IdentityMapper that just passes along its input keys.
The number of mappers run is therefore exactly what you'd expect for any other job: 2.

Watch the training Module 21 from http://hadoopexam.com/index.html/#hadoop-training

Related Questions

Question : Which of the following is a correct statement regarding MapReduce job performance

1. You need to optimize memory, dist IO and networkIO to optimize the Space taken during the Job execution.

2. You need to optimize map and reduce task code execution steps time, to save the total time of job execution.

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4. 1,2

5. 1,2,3

Question : You are a Hadoop Administrator, you need to optimize MapReduce Job. And decided to first look on the Slot configuration.
So what you should keep in your mind, for slot configuration?

1. You can reserve the slot for Map Tasks only

2. One slot can run only one either Map or Reduce Task

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4. 1,2
5. 1,2,3

Question : Select all applies to Slot (Map Slot and Reduce Slot)

1. Total number of reduce slots should be lower than the total number of map slots

2. You can reserve slots for both Reducer and Map tasks

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4. 1,2

5. 1,2,3

Question : In MapR, using the ___________ feature means that each task tracker will reserve one or more ________ slots for executing ____________.

1. ExpressLane, ceephemeral �? , cesmall jobs �?

2. FastLane, non-ephemeral, big jobs

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4. ExpressLane , 'non-ephemeral' , big jobs

Question : Slot configuration is depend on

1. CPU

2. RAM

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4. 1,2

5. 1,2,3

Question : Which of the following options can be used as valid way to optimize MapReduce algorithm
A. Using reducer as Combiner or having Custom combiner (mini-reducer)
B. Compressing intermediate results of MapTasks
C. Optimizing number of reducer
D. Using Speculative Execution
E. Reusing the JVM
F. Configuring sorting properties
G. Configuring java properties

1. C,D,E,F,G
2. A,B,C,D
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4. B,C,D,E,F
5. A,B,C,D,E,F,G