Re: When does Trigger.clear() get called?

Posted by Hequn Cheng on
URL: http://deprecated-apache-flink-user-mailing-list-archive.369.s1.nabble.com/When-does-Trigger-clear-get-called-tp23809p23817.html

Hi Andrew,

Do you use CountWindow? You can switch to TimeWindow to have a test.

I'm not quite familiar with window. I checked the code and found that clear() is called only when timer is triggered, i.e, called at the end of time window.

Hope this helps.

Best, Hequn

On Fri, Oct 12, 2018 at 6:23 AM Andrew Danks <[hidden email]> wrote:

Hello,

I see that the clear() function is implemented for various types of Triggers in the Flink API. For example:

https://github.com/apache/flink/blob/release-1.3/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/triggers/ContinuousProcessingTimeTrigger.java#L87

I am working on a custom Trigger for my application and have implemented clear() in a similar way.

However, having put a breakpoint in this function it doesn’t seem to get called when I expect. The source code says that is called "when a window is purged”[1] but when my Trigger emits a PURGE this function never seems to get called. I am on Flink 1.3.

Hoping someone can shed more light on the purpose of clear() and how/when it gets called

Thanks!

Andrew

[1] https://github.com/apache/flink/blob/release-1.3/flink-streaming-java/src/main/java/org/apache/flink/streaming/api/windowing/triggers/Trigger.java#L111