[jira] [Assigned] (FLINK-8951) Support OVER windows PARTITION BY (rounded) timestamp

["TANG Wen-hui (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-8951?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

TANG Wen-hui reassigned FLINK-8951:
-----------------------------------

    Assignee: TANG Wen-hui

> Support OVER windows PARTITION BY (rounded) timestamp
> -----------------------------------------------------
>
>                 Key: FLINK-8951
>                 URL: https://issues.apache.org/jira/browse/FLINK-8951
>             Project: Flink
>          Issue Type: New Feature
>          Components: Table API & SQL
>            Reporter: Fabian Hueske
>            Assignee: TANG Wen-hui
>            Priority: Minor
>
> There are a few interesting use cases that can be addressed by queries that follow the following pattern
> {code:sql}
> SELECT sensorId COUNT(*) OVER (PARTITION BY CEIL(rowtime TO HOUR) ORDER BY temp ROWS BETWEEN UNBOUNDED preceding AND CURRENT ROW) FROM sensors
> {code}
> Such queries can be used to compute rolling cascading (tumbling) windows with aggregates that are reset in regular intervals. This can be useful for TOP-K per minute/hour/day queries.
> Right now, such {{OVER}} windows are not supported, because we require that the {{ORDER BY}} clause is defined on a timestamp (time indicator) attribute. In order to support this kind of queries, we would require that the {{PARTITION BY}} clause contains a timestamp (time indicator) attribute or a function that is defined on it and which is monotonicity preserving. Once the optimizer identifies this case, it could translate the query into a special time-partitioned OVER window operator.



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