[jira] [Closed] (FLINK-4937) Add incremental group window aggregation for streaming Table API

["Fabian Hueske (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-4937?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Fabian Hueske closed FLINK-4937.
--------------------------------
       Resolution: Fixed
    Fix Version/s: 1.2.0

Fixed with 74e0971a5511c511feb94bee7a0ce39eb9951b62

> Add incremental group window aggregation for streaming Table API
> ----------------------------------------------------------------
>
>                 Key: FLINK-4937
>                 URL: https://issues.apache.org/jira/browse/FLINK-4937
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>    Affects Versions: 1.2.0
>            Reporter: Fabian Hueske
>            Assignee: sunjincheng
>             Fix For: 1.2.0
>
>
> Group-window aggregates for streaming tables are currently not done in an incremental fashion. This means that the window collects all records and performs the aggregation when the window is closed instead of eagerly updating a partial aggregate for every added record. Since records are buffered, non-incremental aggregation requires more storage space than incremental aggregation.
> The DataStream API which is used under the hood of the streaming Table API features [incremental aggregation|https://ci.apache.org/projects/flink/flink-docs-release-1.2/dev/windows.html#windowfunction-with-incremental-aggregation] using a {{ReduceFunction}}.
> We should add support for incremental aggregation in group-windows.
> This is a follow-up task of FLINK-4691.



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