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https://issues.apache.org/jira/browse/FLINK-5047?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Jark Wu updated FLINK-5047:
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    Summary: Add sliding group-windows for batch tables  (was: Add Sliding 
group-windows for batch tables)

> Add sliding group-windows for batch tables
> ------------------------------------------
>
>                 Key: FLINK-5047
>                 URL: https://issues.apache.org/jira/browse/FLINK-5047
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: Jark Wu
>
> Add Slide group-windows for batch tables as described in 
> [FLIP-11](https://cwiki.apache.org/confluence/display/FLINK/FLIP-11%3A+Table+API+Stream+Aggregations).
> There are two ways to implement sliding windows for batch:
> 1. replicate the output in order to assign keys for overlapping windows. This 
> is probably the more straight-forward implementation and supports any 
> aggregation function but blows up the data volume.
> 2. if the aggregation functions are combinable / pre-aggregatable, we can 
> also find the largest tumbling window size from which the sliding windows can 
> be assembled. This is basically the technique used to express sliding windows 
> with plain SQL (GROUP BY + OVER clauses). For a sliding window Slide(10 
> minutes, 2 minutes) this would mean to first compute aggregates of 
> non-overlapping (tumbling) 2 minute windows and assembling consecutively 5 of 
> these into a sliding window (could be done in a MapPartition with sorted 
> input). The implementation could be done as an optimizer rule to split the 
> sliding aggregate into a tumbling aggregate and a SQL WINDOW operator. Maybe 
> it makes sense to implement the WINDOW clause first and reuse this for 
> sliding windows.
> see FLINK-4692 for more discussion



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