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From "Apache Spark (JIRA)" <>
Subject [jira] [Assigned] (SPARK-20586) Add deterministic and distinctLike to ScalaUDF
Date Wed, 03 May 2017 22:36:04 GMT


Apache Spark reassigned SPARK-20586:

    Assignee: Apache Spark  (was: Xiao Li)

> Add deterministic and distinctLike to ScalaUDF
> ----------------------------------------------
>                 Key: SPARK-20586
>                 URL:
>             Project: Spark
>          Issue Type: Bug
>          Components: SQL
>    Affects Versions: 2.2.0
>            Reporter: Xiao Li
>            Assignee: Apache Spark
> Like Hive UDFType, we should allow users to add the extra flags for ScalaUDF too. {{stateful}}/{{impliesOrder}}
are not applicable to ScalaUDF. Thus, we only add the following two flags. 
> - deterministic: Certain optimizations should not be applied if UDF is not deterministic.
Deterministic UDF returns same result each time it is invoked with a particular input. This
determinism just needs to hold within the context of a query.
> - distinctLike: A UDF is considered distinctLike if the UDF can be evaluated on just
the distinct values of a column. Examples include min and max UDFs. This information is used
by metadata-only optimizer.

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