Actually, BoundedOutOfOrderWatermarkGenerator is only used in tests,
the real WatermarkGenerator is code generated in
WatermarkGeneratorCodeGenerator
lec ssmi 于2020年4月17日周五 下午5:19写道：
> I think you are all right. I have I checked the source code of
> WatermarkAssignerOperator, and I have found t
I think you are all right. I have I checked the source code of
WatermarkAssignerOperator, and I have found the WatermarkGenerator passed
in WatermarkAssignerOperator is the interface WatermarkGenerator. And
BoundedOutOfOrderWatermarkGenerator is the only implementation class of
WatermarkGene
WatermarkAssignerOperator is an inner mechanism for generating watermarks.
The "Bounded Out of Orderness" is just one kind of the watermark
expressions, which
is most commonly used.
The main logic of WatermarkAssignerOperator is:
- keep currentWatermark and lastWatermark
- when each element comes
Maybe you are all right. I was more confused .
As the cwiki said, flink could use BoundedOutOfOrderTimestamps ,
[image: image.png]
but I have heard about WatermarkAssignerOperator from Blink developers.
Benchao Li 于2020年4月17日周五 下午4:33写道：
> Hi lec ssmi,
>
> It's a good question. In blink plann
Hi lec ssmi,
It's a good question. In blink planner, we use code gen to handle watermark
expression.
And in `WatermarkAssignerOperator` we calculate current watermark when each
element comes in.
If the watermark - lastEmitedWatermark > watermark interval, we will emit
the new watermark.
So it's n
