[jira] [Updated] (SPARK-3572) Internal API for User-Defined Types

["Patrick Wendell (JIRA)" <ji...@apache.org>]

     [ https://issues.apache.org/jira/browse/SPARK-3572?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Patrick Wendell updated SPARK-3572:
-----------------------------------
    Summary: Internal API for User-Defined Types  (was: Support register UserType in SQL)

> Internal API for User-Defined Types
> -----------------------------------
>
>                 Key: SPARK-3572
>                 URL: https://issues.apache.org/jira/browse/SPARK-3572
>             Project: Spark
>          Issue Type: New Feature
>          Components: SQL
>            Reporter: Xiangrui Meng
>            Assignee: Joseph K. Bradley
>
> If a user knows how to map a class to a struct type in Spark SQL, he should be able to register this mapping through sqlContext and hence SQL can figure out the schema automatically.
> {code}
> trait RowSerializer[T] {
>   def dataType: StructType
>   def serialize(obj: T): Row
>   def deserialize(row: Row): T
> }
> sqlContext.registerUserType[T](clazz: classOf[T], serializer: classOf[RowSerializer[T]])
> {code}
> In sqlContext, we can maintain a class-to-serializer map and use it for conversion. The serializer class can be embedded into the metadata, so when `select` is called, we know we want to deserialize the result.
> {code}
> sqlContext.registerUserType(classOf[Vector], classOf[VectorRowSerializer])
> val points: RDD[LabeledPoint] = ...
> val features: RDD[Vector] = points.select('features).map { case Row(v: Vector) => v }
> {code}



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