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From "ASF GitHub Bot (JIRA)" <j...@apache.org>
Subject [jira] [Commented] (FLINK-5658) Add event time OVER ROWS BETWEEN UNBOUNDED PRECEDING aggregation to SQL
Date Tue, 28 Mar 2017 07:42:41 GMT

    [ https://issues.apache.org/jira/browse/FLINK-5658?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=15944706#comment-15944706
] 

ASF GitHub Bot commented on FLINK-5658:
---------------------------------------

Github user fhueske commented on a diff in the pull request:

    https://github.com/apache/flink/pull/3386#discussion_r108352888
  
    --- Diff: flink-libraries/flink-table/src/main/scala/org/apache/flink/table/plan/nodes/datastream/DataStreamOverAggregate.scala
---
    @@ -112,7 +113,12 @@ class DataStreamOverAggregate(
                   "condition.")
             }
           case _: RowTimeType =>
    -        throw new TableException("OVER Window of the EventTime type is not currently
supported.")
    +        if (overWindow.lowerBound.isUnbounded && overWindow.upperBound.isCurrentRow)
{
    +          createUnboundedAndCurrentRowEventTimeOverWindow(inputDS)
    --- End diff --
    
    Updated JIRA [FLINK-5658](https://issues.apache.org/jira/browse/FLINK-5658). @sunjincheng121,
not sure if that was an issue with your permissions. It is not possible to modify a closed
issue. You need to reopen it first.


> Add event time OVER ROWS BETWEEN UNBOUNDED PRECEDING aggregation to SQL
> -----------------------------------------------------------------------
>
>                 Key: FLINK-5658
>                 URL: https://issues.apache.org/jira/browse/FLINK-5658
>             Project: Flink
>          Issue Type: Sub-task
>          Components: Table API & SQL
>            Reporter: Fabian Hueske
>            Assignee: hongyuhong
>             Fix For: 1.3.0
>
>
> The goal of this issue is to add support for OVER RANGE aggregations on event 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 rowTime() ROWS BETWEEN UNBOUNDED PRECEDING AND
CURRENT ROW) AS sumB,
>   MIN(b) OVER (PARTITION BY c ORDER BY rowTime() ROWS 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 rowTime() as parameter. rowTime() is a parameterless
scalar function that just indicates processing time mode.
> - bounded PRECEDING is not supported (see FLINK-5655)
> - 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.
> An event-time OVER ROWS window will not be able to handle late data, because this would
mean in insert a row into a sorted order shift all other computations. This would be too expensive
to maintain. Therefore, we will throw an error if a user tries to use an event-time OVER ROWS
window with late data handling.
> 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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