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

601

Explain combiners.

628

Explain what combiners are and when you should use a combiner in a mapreduce job?

613

What are the advantages of using map side join in mapreduce?

645

Explain the differences between a combiner and reducer

650

How can we control particular key should go in a specific reducer?

913

What happens when the node running the map task fails before the map output has been sent to the reducer?

647

What is sqoop in Hadoop ?

683

what is distributed cache in mapreduce framework?

672

What are the identity mapper and reducer in MapReduce?

780

How to change a number of mappers running on a slave in MapReduce?

789

Illustrate a simple example of the working of MapReduce.

629

When is it not recommended to use MapReduce paradigm for large scale data processing?

654

What is a scarce system resource?

652

Why Mapreduce output written in local disk?

998