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Posted to user-zh@flink.apache.org by Kyle Zhang <sh...@gmail.com> on 2020/11/24 05:33:43 UTC
ProcessingTime下的watermark
Hi,
使用flink1.11,在SQL ddl中基于process time声明watermark报错
SQL validation failed. Watermark can not be defined for a processing time
attribute column.
文档里关于watermark的解释也基本是跟eventTime在一起[1]
我想问的是基于processingTime的流处理是不需要watermark,还是被flink优化,不需要我们关心?
[1]
https://ci.apache.org/projects/flink/flink-docs-release-1.11/concepts/timely-stream-processing.html#event-time-and-watermarks
Best
Re: ProcessingTime下的watermark
Posted by Xingbo Huang <hx...@gmail.com>.
Hi,
watermark是对于数据的eventTime没有顺序到来帮助何时触发计算用的,你如果用processingTime来,processingTime肯定是递增的,就不存在乱序这个概念了,就不需要watermark了。
Best,
Xingbo
Kyle Zhang <sh...@gmail.com> 于2020年11月24日周二 下午1:34写道:
> Hi,
> 使用flink1.11,在SQL ddl中基于process time声明watermark报错
>
> SQL validation failed. Watermark can not be defined for a processing time
> attribute column.
>
> 文档里关于watermark的解释也基本是跟eventTime在一起[1]
> 我想问的是基于processingTime的流处理是不需要watermark,还是被flink优化,不需要我们关心?
>
> [1]
>
> https://ci.apache.org/projects/flink/flink-docs-release-1.11/concepts/timely-stream-processing.html#event-time-and-watermarks
>
> Best
>