[jira] [Closed] (FLINK-8782) Rmove count agg if it is generated for sum agg in over window

["Kurt Young (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/FLINK-8782?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Kurt Young closed FLINK-8782.
-----------------------------
    Resolution: Unresolved

> Rmove count agg if it is generated for sum agg in over window
> -------------------------------------------------------------
>
>                 Key: FLINK-8782
>                 URL: https://issues.apache.org/jira/browse/FLINK-8782
>             Project: Flink
>          Issue Type: Improvement
>          Components: Table API & SQL
>            Reporter: Hequn Cheng
>            Priority: Major
>
> Currently, sum agg in over window will generate another count agg which is redundant and affect performance. 
> For the following sql:
> {code:java}
> val sqlQuery = "SELECT a, " +
>  " SUM(b) OVER (" +
>  " PARTITION BY a ORDER BY proctime ROWS BETWEEN 3 PRECEDING AND CURRENT ROW) " +
>  "FROM MyTable"{code}
> the corresponding {{LogicalProject}} generated by over is:
> {code:java}
> CASE(>(COUNT($1) OVER (PARTITION BY $0 ORDER BY $5 ROWS BETWEEN 3 PRECEDING AND CURRENT ROW), 0), CAST($SUM0($1) OVER (PARTITION BY $0 ORDER BY $5 ROWS BETWEEN 3 PRECEDING AND CURRENT ROW)):BIGINT, null){code}
> count is used to return null if count is zero while this logic is redundant since sum agg function will return null in this case.



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