Spark RDD-2-持久化&容错机制
rdd.cache 默认调用persisi，之缓存内存 def cache(): this.type = persist() rdd.persist() def persist(): this.type = persist(StorageLevel.MEMORY_ONLY) rdd.unpersist(true) 手动释放缓存RDD占用的内存、磁盘存储资源 rdd.ch...
