pipelinedb 滑动窗口

Posted 2021-01-01 rongfengliang-荣锋亮

滑动窗口可以方便的让我们进行一段时间的数据分析

几个主要函数

• clock_timestamp

内置的函数，总是返回当前的时间戳

• arrival_timestamp

事件达到的时间

单滑动窗口

• 参考

CREATE CONTINUOUS VIEW recent_users WITH (sw = ‘1 minute‘) AS
   SELECT user_id::integer FROM stream;

相应的pipelinedb 会转换为：
CREATE CONTINUOUS VIEW recent_users AS
   SELECT user_id::integer FROM stream
WHERE (arrival_timestamp > clock_timestamp() - interval ‘1 minute‘);

多窗口

是一个基于单滑动窗口的view

• 参考例子

CREATE CONTINUOUS VIEW sw0 WITH (sw = ‘1 hour‘) AS SELECT COUNT(*) FROM event_stream;
CREATE VIEW sw1 WITH (sw = ‘5 minutes‘) AS SELECT * FROM sw0;
CREATE VIEW sw2 WITH (sw = ‘10 minutes‘) AS SELECT * FROM sw0;

参考资料

http://docs.pipelinedb.com/sliding-windows.html