Working of mapreduce

Question

Describe working of the mapreduce.

Answer 1

The processing may takes place on data that are in the file system (un structured) or in the database (structured). The mapreduce framework primarily works over two steps:

a) Map step: During this step master node accepts an input (problem) and splits it into the smaller problems. Now node distributes small sub problems to the worker node so that they may solve the problem.

b) Decrease the step: Once the sub problem is solved by worker node, node returns a solution to master node that accepts all solutions of worker node and re-compiles them into the solution. This solution is for the input which was givne to the master node.