[jira] [Commented] (FLINK-40987) Allow overriding a table's watermark per table reference via OPTIONS hint

["Gustavo de Morais (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-40987?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=18127787#comment-18127787 ] 

Gustavo de Morais commented on FLINK-40987:
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There's an alternative FLIP under discussion which covers the functionality here [https://lists.apache.org/thread.html/52km3zy2ospdrg7nwcsdbw7hfwvmb4f6|https://lists.apache.org/thread.html/52km3zy2ospdrg7nwcsdbw7hfwvmb4f6.]

> Allow overriding a table's watermark per table reference via OPTIONS hint
> -------------------------------------------------------------------------
>
>                 Key: FLINK-40987
>                 URL: https://issues.apache.org/jira/browse/FLINK-40987
>             Project: Flink
>          Issue Type: New Feature
>          Components: Table SQL / API
>            Reporter: Gustavo de Morais
>            Priority: Major
>
> A table's watermark can only be changed through DDL (ALTER TABLE ... MODIFY/DROP WATERMARK, or CREATE TABLE ... LIKE). This affects every query on the table or requires a second table. The OPTIONS hint (FLIP-296) can tune watermark emission, but not the definition itself.
> Motivation: the same table is often read by queries with different needs. A dashboard wants a short delay, a billing job tolerates an hour of late data, a copy job needs no watermark. Connectors are also starting to override the watermark inside the source, without the planner knowing ([apache/fluss#3266|https://github.com/apache/fluss/pull/3266]).
> Idea: let the OPTIONS hint override the watermark for one table reference, with the same semantics as the DDL:
> {code:java}
> SELECT * FROM orders /*+ OPTIONS('scan.watermark.delay' = '1 h') */;
> SELECT * FROM orders /*+ OPTIONS('scan.watermark.column' = 'ship_time') */;
> SELECT * FROM orders /*+ OPTIONS('scan.watermark.enabled' = 'false') */;{code}
> No new semantics: each hint behaves like MODIFY/DROP WATERMARK, scoped to one table reference. The hinted watermark would be applied during validation, reusing the CREATE TABLE / LIKE schema resolution, so planner and source stay consistent.
> This ticket is to collect feedback. Option names are placeholders (a single watermark-expression option is an alternative).



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