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Can you explain how do ‘map’ and ‘reduce’ work?

Answer Posted / Amar

The MapReduce programming model in Apache Hadoop is a software framework for processing large datasets. It consists of two main components: Map and Reduce.n
1. Map: The map function takes input data (key-value pairs) as input, performs a transformation on each record independently, and generates intermediate key-value pairs as output. This process is distributed across multiple nodes in the Hadoop cluster.n
2. Reduce: After the map phase, all intermediate key-value pairs are sorted by their keys. The reduce function then takes these sorted sets of values for each key and combines them to produce a smaller set of key-value pairs as output. This step is also distributed across multiple nodes, but unlike the map phase, the same reduce task processes all data associated with a given key.nnIn simple terms, the map function transforms input data, and the reduce function aggregates the results.

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