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From "Jark Wu (JIRA)" <j...@apache.org>
Subject [jira] [Updated] (FLINK-5047) Add Sliding group-windows for batch tables
Date Thu, 10 Nov 2016 03:19:58 GMT

     [ https://issues.apache.org/jira/browse/FLINK-5047?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel

Jark Wu updated FLINK-5047:
    Summary: Add Sliding group-windows for batch tables  (was: Add tumbling 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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