@rbiswas yea Actually splitSize is equal to block size, so I want to know if we assign block size at SplitTime then job contains that memory for whole process or after reducer any changes; ... View more

Nope, reducers don't communicate with each other and neither the mappers do. All of them runs in a separate JVM containers and don't have information of each other. AppMaster is the demon which takes care and manage these JVM based containers (Mapper/Reducer). ... View more