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

MapReduce Interview Questions

Questions Answers Views Company eMail

Mention when to use Map reduce mode?

628

What is shuffleing in mapreduce?

648

Does mapreduce programming model provide a way for reducers to communicate with each other? In a mapreduce job can a reducer communicate with another reducer?

677

How would you tackle calculating the number of unique visitors for each hour by mining a huge apache log? You can use post processing on the output of the mapreduce job.

824

Describe what happens to a mapreduce job from submission to output?

665

If reducers do not start before all mappers finish then why does the progress on mapreduce job shows something like map(50%) reduce(10%)? Why reducers progress percentage is displayed when mapper is not finished yet?

712

What are mapreduce new and old apis while writing map reduce program?. Explain how it works

651

When should you use a reducer?

630

Can you tell us how many daemon processes run on a hadoop system?

593

Difference between mapreduce and spark

684

What is identity mapper and identity reducer?

644

What is heartbeat in hdfs? Explain.

681

What is identity mapper and chain mapper?

669

Name job control options specified by mapreduce.

706

What is heartbeat in hdfs?

646

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Un-Answered Questions { MapReduce }

Why do we need MapReduce during Pig programming?

643

What does a split do?

621

How is reporting controlled in hadoop?

782

how to proceed to write your first mapreducer program?

1343

What is a IdentityMapper and IdentityReducer in MapReduce ?

945

what is WebDAV in Hadoop?

731

How many numbers of reducers run in Map-Reduce Job?

610

How to set the number of mappers to be created in MapReduce?

638

In mapreduce what is a scarce system resource? Explain?

669

Is it mandatory to set input and output type/format in MapReduce?

732

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

650

How many Reducers run for a MapReduce job?

689

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

630

Can we set the number of reducers to zero in MapReduce?

703

How will you submit extra files or data ( like jars, static files, etc. ) For a mapreduce job during runtime?

656

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