MapReduce Interview Questions, Answers for Freshers and Experienced asked in various Company Job Interviews

MapReduce Interview Questions

Questions Answers Views Company eMail

How many times combiner is called on a mapper node in Hadoop?

599

Explain about the partitioning, shuffle and sort phase in MapReduce?

776

Does Partitioner run in its own JVM or shares with another process?

663

Why MapReduce uses the key-value pair to process the data?

588

What is Distributed Cache in the MapReduce Framework?

582

How to create a custom key and custom value in MapReduce Job?

642

Is reduce-only job possible in Hadoop MapReduce?

652

How to optimize MapReduce Job?

617

In MapReduce how to change the name of the output file from part-r-00000?

602

In MapReduce Data Flow, when Combiner is called?

601

Differentiate Reducer and Combiner in Hadoop MapReduce?

627

What is the key- value pair in MapReduce?

724

A number of combiners can be changed or not in MapReduce?

596

How to write a custom partitioner for a Hadoop MapReduce job?

601

What is the need of MapReduce in Hadoop?

593

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Un-Answered Questions { MapReduce }

What are the various input and output types supported by mapreduce?

566

Explain combiners.

586

What is the key- value pair in MapReduce?

724

how is data partitioned before it is sent to the reducer if no custom partitioner is defined in Hadoop?

743

What do you understand by the term Straggler ?

636

Explain what are the basic parameters of a mapper?

755

What are the benefits of Spark over MapReduce?

577

How to get the single file as the output from MapReduce Job?

591

What is a partitioner and how the user can control which key will go to which reducer?

888

What is difference between an input split and hdfs block?

605

Is it legal to set the number of reducer task to zero? Where the output will be stored in this case?

614

What is heartbeat in hdfs?

613

Clarify what combiners are and when you should utilize a combiner in a map reduce job?

560

How do reducers communicate with each other?

601

Is it important for Hadoop MapReduce jobs to be written in Java?

776

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