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Posted to issues@flink.apache.org by "sunjincheng (JIRA)" <ji...@apache.org> on 2018/11/22 09:15:00 UTC

[jira] [Updated] (FLINK-4557) Table API Stream Aggregations

     [ https://issues.apache.org/jira/browse/FLINK-4557?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

sunjincheng updated FLINK-4557:
-------------------------------
    Component/s:     (was: Table API & SQL)

> Table API Stream Aggregations
> -----------------------------
>
>                 Key: FLINK-4557
>                 URL: https://issues.apache.org/jira/browse/FLINK-4557
>             Project: Flink
>          Issue Type: New Feature
>            Reporter: Timo Walther
>            Priority: Major
>             Fix For: 1.4.0
>
>
> The Table API is a declarative API to define queries on static and streaming tables. So far, only projection, selection, and union are supported operations on streaming tables.
> This issue and the corresponding FLIP proposes to add support for different types of aggregations on top of streaming tables. In particular, we seek to support:
> *Group-window aggregates*, i.e., aggregates which are computed for a group of elements. A (time or row-count) window is required to bound the infinite input stream into a finite group.
> *Row-window aggregates*, i.e., aggregates which are computed for each row, based on a window (range) of preceding and succeeding rows.
> Each type of aggregate shall be supported on keyed/grouped or non-keyed/grouped data streams for streaming tables as well as batch tables.
> Since time-windowed aggregates will be the first operation that require the definition of time, we also need to discuss how the Table API handles time characteristics, timestamps, and watermarks.
> The FLIP can be found here: 
> https://cwiki.apache.org/confluence/display/FLINK/FLIP-11%3A+Table+API+Stream+Aggregations



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