[
https://issues.apache.org/jira/browse/FLINK-9422?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16487575#comment-16487575
]
Hequn Cheng commented on FLINK-9422:
------------------------------------
Hi [~fhueske] [~RuidongLi] , I am not sure if we need to add a dedicated
{{UNION}} operator since we can solve it by
[FLNIK-8566|https://issues.apache.org/jira/browse/FLINK-8566] and
[FLINK-8594|https://issues.apache.org/jira/browse/FLINK-8594], right?
> Dedicated operator for UNION on streaming tables with time attributes
> ---------------------------------------------------------------------
>
> Key: FLINK-9422
> URL: https://issues.apache.org/jira/browse/FLINK-9422
> Project: Flink
> Issue Type: Improvement
> Components: Table API & SQL
> Reporter: Fabian Hueske
> Assignee: Ruidong Li
> Priority: Minor
>
> We can implement a dedicated operator for a {{UNION}} operator on tables with
> time attributes. Currently, {{UNION}} is translated into a {{UNION ALL}} and
> a subsequent {{GROUP BY}} on all attributes without aggregation functions.
> The state of the grouping operator is only clean up using state retention
> timers.
> The dedicated operator would leverage the monotonicity property of the time
> attribute and watermarks to automatically clean up its state.
--
This message was sent by Atlassian JIRA
(v7.6.3#76005)
