[jira] [Created] (FLINK-9422) Dedicated operator for UNION on streaming tables with time attributes

[Shang Yuanchun (Jira)]

Fabian Hueske created FLINK-9422:
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             Summary: 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


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.



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