Explain the difference between a MapReduce InputSplit and HDFS block?

696

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

692

What is the Job interface in MapReduce framework?

951

Explain JobConf in MapReduce.

848

What happens if the quantity of the reducer is 0 in mapreduce?

637

What is shuffleing in mapreduce?

694

Explain the features of Apache Spark because of which it is superior to Apache MapReduce?

656

For a job in Hadoop, is it possible to change the number of mappers to be created?

828

When Namenode is down what happens to job tracker?

753

What Are Good Use Cases For Impala As Opposed To Hive Or MapReduce?

641

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

722

What is the difference between HDFS block and input split?

934

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?

757

Explain what is shuffling in mapreduce?

668

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

865