偶然发现Spark RDD 中的 sortBy 是个特殊的 transform 算子，它居然可以像 action 算子一样触发 job。 这是为什么呢？来了解了解。
Let’s start learning the PowerPhrases at Work. There has three parts:
Managing Your Boss
Communicating With Coworker
Magic Phrases for Managers
Effective Email
Maybe someone of you have heard about《PowerPhrases》which have another name called “The perfect words to Say it Right and Get the Results you want”.
Is it looks interesting for you ? let’s start read it.
Spark 3.0 已经release了，来看看有什么新东西。
进入第七章：《Spark 应用的优化与调整》。
进入第六章：《Spark SQL 和 Datasets》。