[jira] [Commented] (FLINK-3715) Move Accumulating/Discarding from Trigger to WindowOperator

["Elias Levy (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-3715?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15305082#comment-15305082 ] 

Elias Levy commented on FLINK-3715:
-----------------------------------

As mentioned on the Google doc, this may not be flexible enough.  If you have windows where you are implementing early firing using multiple triggers, you will want to keep the elements in the window during early firing, but purge them at the end of the window firing.

> Move Accumulating/Discarding from Trigger to WindowOperator
> -----------------------------------------------------------
>
>                 Key: FLINK-3715
>                 URL: https://issues.apache.org/jira/browse/FLINK-3715
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Streaming
>            Reporter: Aljoscha Krettek
>
> As mentioned in https://docs.google.com/document/d/1Xp-YBf87vLTduYSivgqWVEMjYUmkA-hyb4muX3KRl08/edit#heading=h.pyk1sn8f33q2 we should move the decision of whether to {{PURGE}} a window upon firing from the {{Trigger}} to the {{WindowOperator}}. This also requires to add API so that the user can specify whether windows should be purged upon trigger firing (discarding) or kept (accumulating).
> As mentioned in the above doc, the {{Trigger}} can react with 4 results right now: {{CONTINUE}}, {{FIRE}}, {{PURGE}}, {{FIRE_AND_PURGE}}. The behavior of a trigger is not apparent if not looking at the code of the trigger, this has confused a number of users. With the new regime, a {{Trigger}} can just decide whether to {{CONTINUE}} or {{FIRE}}. The setting of accumulating/discarding decides whether to purge the window or keep it.
> This depends on FLINK-3714 where we introduce an "allowed lateness" setting. Having a choice between accumulating and discarding only makes sense with an allowed lateness greater zero. Otherwise no late elements could ever arrive that would go into the kept windows.



--
This message was sent by Atlassian JIRA
(v6.3.4#6332)