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https://issues.apache.org/jira/browse/CALCITE-4146?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17170135#comment-17170135
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Rui Wang commented on CALCITE-4146:
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hmmm the EMIT will be at end of SQL query and it will propagate through every
relational operator. However, technically, I feel like only
TableFuncitonScanRel that works with a stream will be affected. You can think
of that a macro batch streaming system implements it. In that system, EMTI
controls the size and frequency of each macro batch (from
TableFuncitonScanRel), and all other join, sort, aggregate are applied on each
macro batch.
> Implement EMIT AFTER WATERMARK
> ------------------------------
>
> Key: CALCITE-4146
> URL: https://issues.apache.org/jira/browse/CALCITE-4146
> Project: Calcite
> Issue Type: Sub-task
> Reporter: Rui Wang
> Assignee: Rui Wang
> Priority: Major
>
> The goal is to support the following syntax
> {code:sql}
> SELECT clause
> FROM TUMBLE/HOP/SESSION
> EMIT AFTER WATERMARK
> {code}
> note that "EMIT AFTER WATERMARK" is the new thing.
> "EMIT AFTER WATERMARK" is proposed in [1]. This idea proposes a way to allow
> streaming SQL queries control materialization latency. More specifically, it
> means emit elements in a window once the watermark passes the end of that
> window.
> There are more context discussed in [2][3].
> [1]: https://arxiv.org/pdf/1905.12133.pdf
> [2]:
> https://issues.apache.org/jira/browse/CALCITE-3272?focusedCommentId=17166580&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-17166580
> [3]:https://lists.apache.org/thread.html/r5bd9a6f7af2c0cd81aecd4de512fd889fbf15f112cc3704f188b1d4f%40%3Cdev.calcite.apache.org%3E
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