overview
Oracle's cost-based optimizer (COB) uses statistics to calculate the selectivity (the fraction of rows in a table that the SQL statement's predicate chooses) of predicates and to estimate ...
需求1:给定一个RDD[Double],进行计算,该RDD的统计信息(count,mean,stdev,max,min)
代码:
def main(args: Array[String]): Unit = {
val conf = new SparkConf().setMaster("local[2]").setAppName(this.ge...