private static int setReducerCount ( long fileCount , JobConf job , JobClient client ) { // calculate the max number of reducers. int numReducers = Math . max ( job . getInt ( MAX_REDUCE_LABEL , MAX_REDUCERS_DEFAULT ) , ( int ) ( fileCount / job . getInt ( MAX_FILES_PER_REDUCER_LABEL , MAX_FILES_PER_REDUCER_DEFAULT ) ) ) ; // make sure we at least have 1. numReducers = Math . max ( numReducers , 1 ) ; job . setNumReduceTasks ( numReducers ) ; return numReducers ; }
Calculate how many reducers to run .