[jira] [Commented] (FLINK-5657) Add processing time OVER RANGE BETWEEN UNBOUNDED PRECEDING aggregation to SQL

["Yuhong Hong (JIRA)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/FLINK-5657?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15853890#comment-15853890 ] 

Yuhong Hong commented on FLINK-5657:
------------------------------------

Hi Fabian, I'm interested in implementing this issue.
As unbounded  record, we can just keep a reducing result per group, 
so we can add an DataStreamGroupReduce similar to StreamGroupedReduce,
and it's a simplified GlobalWindow which no keeping the records to reduce memory.
Another problem is that parse the sql to relnode. I agree with @radu that use the LogicalWindow, 
but if only use volcanoplanner, it seems that the optimiztion ProjectToWindowRule can not effect.
I expect we can use both hep planner and volcanoplanner like Samza. 
I'm not sure if it's a good solution, hope some suggestion.


> Add processing time OVER RANGE BETWEEN UNBOUNDED PRECEDING aggregation to SQL
> -----------------------------------------------------------------------------
>
>                 Key: FLINK-5657
>                 URL: https://issues.apache.org/jira/browse/FLINK-5657
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: Fabian Hueske
>            Assignee: sunjincheng
>
> The goal of this issue is to add support for OVER RANGE aggregations on processing time streams to the SQL interface.
> Queries similar to the following should be supported:
> {code}
> SELECT 
>   a, 
>   SUM(b) OVER (PARTITION BY c ORDER BY procTime() RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS sumB,
>   MIN(b) OVER (PARTITION BY c ORDER BY procTime() RANGE BETWEEN UNBOUNDED PRECEDING AND CURRENT ROW) AS minB
> FROM myStream
> {code}
> The following restrictions should initially apply:
> - All OVER clauses in the same SELECT clause must be exactly the same.
> - The PARTITION BY clause is optional (no partitioning results in single threaded execution).
> - The ORDER BY clause may only have procTime() as parameter. procTime() is a parameterless scalar function that just indicates processing time mode.
> - bounded PRECEDING is not supported (see FLINK-5654)
> - FOLLOWING is not supported.
> The restrictions will be resolved in follow up issues. If we find that some of the restrictions are trivial to address, we can add the functionality in this issue as well.
> This issue includes:
> - Design of the DataStream operator to compute OVER ROW aggregates
> - Translation from Calcite's RelNode representation (LogicalProject with RexOver expression).



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