What type of the inputs and outputs do the map and reduce functions in MapReduce use? How are the inputs and outputs of the two functions connected?
The input of map function in MapReduce is a document
The output of map function in MapReduce is a sequence of tuple(word,1)
The input of reduce function in MapReduce is a key and a list of all values of that key
The output of reduce function in MapReduce is a sequence of tuples(word, number of occurrences)
Is it correct? what about the connected functions, is combiner?