Dataset&Datastream API
1)熟悉两套API:DataSet/DataStream Java/Scala
MapReduce ==》 Hive SQL
Spark ==> Spark SQL
Flink ==> SQL
2)Flink是支持批处理/流处理,如何做到API层面的统一
==> Table & SQL API 关系型API
Everybody knows SQL
env.setstreamTimeCharacteristic(TimeCharacteristic.EventTime)
思考:默认的TimeCharacteristic是什么?
窗口分配器:定义如何将数据分配给窗口
A WindowAssigner is responsible for assigning each incoming element to one or more windows
每个传入的数据分配给一个或者多个窗口
tumbling windows滚动窗口
have a fixed size and do not overlap
sliding windows 滑动窗口
overlapping
session windows 会话窗口
global windows 全局窗口
[ start timestamp , end timestamp)
Flink流计算编程-watermark(水位线)简介
https://blog.csdn.net/lmalds/article/details/52704170