Jan 11, 2020 in Big Data | Hadoop
Q: What are the core methods of a Reducer in Hadoop?

1 Answer

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Jan 11, 2020

The main task of Reducer is to reduce a larger set of data that shares a key to a smaller set of data. In Hadoop, Reducer has following three core methods:

1. setup(): At the start of a task, setup() method is called to configure various parameters for Reducer.

2. reduce(): This is the main


operation of Reducer. In reduce() method we define the task that has to be done for a set of values that share a key.

3. cleanup(): Once reduce() task is done, we can use cleanup() to clean any intermediate data or temporary files.

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