Describe how you would implement a MapReduce job consisting of Map and Reduce

description for the specific query. Just describe, in your

own words, what the Map and Reduce tasks are going to do in the specific query a. Map task reads the input

file and produces (key, value) pairs. Reduce task takes a list of (key, value) pairs for each

key and combines all values for each key.

Please remember that Map operates on individual blocks and Reduce on individual keys

with a set of values. Thus, for Mapper you need to state what your code does given a

block of data (i.e., for each block, not for the whole file) and for Reduce you need to state

what your reducer does for each key (without being able to see other key). Broad answers that do related the the specific query below will not receive any credit.

a)

Describe how to implement the following query in MapReduce

SELECT SUM(lo_extendedprice)

FROM lineorder, dwdate

WHERE lo_orderdate = d_datekey

AND d_yearmonth = 'Jan1995'

AND lo_discount BETWEEN 4 AND 7;