MapReduce 2004

distributedsystems

Computation model, takes a set of key/values and produces a set of key/values

• functional style programming, for ease of parallelization, using the id
• example, distributed grep
• written in Java, consists of a Mapper and Reducer

List(1,2,3,4,5).map(x => x * x) // List(1,4,9,16,25)
List(1,2,3,4,5).reduce(_+_) // 15