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

MapReduce Interview Questions

Questions Answers Views Company eMail

What are combiners? When should I use a combiner in my MapReduce Job?

746

In Map Reduce why map write output to Local Disk instead of HDFS?

731

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

724

How does Mappers run method works?

701

How does MapReduce framework view its input internally?

677

What are the steps involved in MapReduce framework?

708

What is the Job interface in MapReduce framework?

725

How to overwrite an existing output file during execution of mapreduce jobs?

MRO,

928

Detail description of the Reducer phases?

674

Can there be no Reducer?

682

What is the utility of using Writable Comparable Custom Class in Map Reduce code?

718

What is the core of the job in MapReduce framework?

660

MapReduce Types and Formats and Setting up a Hadoop Cluster?

708

It can be possible that a Job has 0 reducers?

735

Why Mapreduce output written in local disk?

707

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Un-Answered Questions { MapReduce }

What is OutputCommitter?

611

what is distributed cache in mapreduce framework?

464

Explain JobConf in MapReduce.

617

How do ‘map’ and ‘reduce’ work?

466

What is heartbeat in hdfs?

490

What is Mapper in Hadoop MapReduce?

494

Explain the general mapreduce algorithm

455

what is Speculative Execution?

629

Can there be no Reducer?

682

In MapReduce, ideally how many mappers should be configured on a slave?

483

What is the fundamental difference between a MapReduce InputSplit and HDFS block?

442

When is it not recommended to use MapReduce paradigm for large

451

Explain the process of spilling in Hadoop MapReduce?

450

Which Sorting algorithm is used in Hadoop MapReduce?

422

What is the input type/format in MapReduce by default?

848

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