Github user HyukjinKwon commented on a diff in the pull request: https://github.com/apache/spark/pull/22009#discussion_r223982672 --- Diff: sql/core/src/main/scala/org/apache/spark/sql/execution/datasources/v2/DataSourceV2Relation.scala --- @@ -169,15 +174,16 @@ object DataSourceV2Relation { options: Map[String, String], tableIdent: Option[TableIdentifier] = None, userSpecifiedSchema: Option[StructType] = None): DataSourceV2Relation = { - val reader = source.createReader(options, userSpecifiedSchema) + val readSupport = source.createReadSupport(options, userSpecifiedSchema) --- End diff -- Looks not directly related with this PR but I think this is a good place to ask. Why do we make a readsupport in write path? https://github.com/apache/spark/blob/e06da95cd9423f55cdb154a2778b0bddf7be984c/sql/core/src/main/scala/org/apache/spark/sql/DataFrameWriter.scala#L249 Retrieving the physical schema of the underlying storage is potentially expensive. Actually even worse: it looks odd that write path requires read side's schema. Which schema should we expect here in write path?
--- --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org