Question

What are the core methods of a Reducer? 

Answer 1

The 3 core methods of a reducer are –

 

1)setup () – This method of the reducer is used for configuring various parameters like the input data size, distributed cache, heap size, etc.

 

Function Definition- public void setup (context)

 

2)reduce () it is heart of the reducer which is called once per key with the associated reduce task.

 

Function Definition -public void reduce (Key,Value,context)

 

3)cleanup () - This method is called only once at the end of reduce task for clearing all the temporary files.

 

Function Definition -public void cleanup (context)