[jira] [Work started] (HIVE-24908) Adding Respect/Ignore nulls as a UDAF parameter is ambiguous

["Krisztian Kasa (Jira)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/HIVE-24908?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Work on HIVE-24908 started by Krisztian Kasa.
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> Adding Respect/Ignore nulls as a UDAF parameter is ambiguous
> ------------------------------------------------------------
>
>                 Key: HIVE-24908
>                 URL: https://issues.apache.org/jira/browse/HIVE-24908
>             Project: Hive
>          Issue Type: Bug
>          Components: UDF
>            Reporter: Krisztian Kasa
>            Assignee: Krisztian Kasa
>            Priority: Major
>
> Both function calls translated to the same UDAF call:
> {code}
> SELECT lead(a, 2, true) ...
> SELECT lead(a, 2) IGNORE NULLS ...
> {code}
> IGNORE NULLS is passed as an extra constant boolean parameter to the UDAF
> https://github.com/apache/hive/blob/eed78dfdcb6dfc2de400397a60de12e6f62b96e2/ql/src/java/org/apache/hadoop/hive/ql/optimizer/calcite/translator/ASTConverter.java#L743
> However the semantics of the two function calls has different semantics:
> * *lead(a, 2, true)* - 'true' is the default value: "The value of DEFAULT is returned as the result if there is no row corresponding to the OFFSET number of rows before R within P (for the lag function) or after R within P (for the lead function)"
> * *lead(a, 2) IGNORE NULLS* - For each row in the current window find the 2nd not-NULL value starting directly after the current row. 



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