Hi, In the hadoop documentation it says that all key-value classes need to implement Writable to allow serialization and de-serialization of outputs between mappers and reducers. Is this also necessary for key/value pairs sent between the RecordReader and the Mapper (as well as the Reducer and the RecordWriter)? I assume that each of these two cases, classes are instantiated in the same VM. So is it safe to assume that key/value pairs are sent by reference instead of serialization/deserialization? If so, my specific application may get a performance boost. Please do let me know if this so.
Thanks and best regards, Dev
