Github user rdblue commented on a diff in the pull request:
https://github.com/apache/spark/pull/12313#discussion_r66688732
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/Analyzer.scala
---
@@ -505,6 +506,117 @@ class Analyzer(
}
}
+ object ResolveOutputColumns extends Rule[LogicalPlan] {
+ def apply(plan: LogicalPlan): LogicalPlan = plan.transform {
+ case ins @ InsertIntoTable(relation: LogicalPlan, partition, _, _,
_, _)
+ if relation.resolved && !ins.resolved =>
+ resolveOutputColumns(ins, expectedColumns(relation, partition),
relation.toString)
+ }
+
+ private def resolveOutputColumns(
+ insertInto: InsertIntoTable,
+ columns: Seq[Attribute],
+ relation: String) = {
+ val resolved = if (insertInto.isMatchByName) {
+ projectAndCastOutputColumns(columns, insertInto.child, relation)
+ } else {
+ castAndRenameOutputColumns(columns, insertInto.child, relation)
+ }
+
+ if (resolved == insertInto.child.output) {
+ insertInto
+ } else {
+ insertInto.copy(child = Project(resolved, insertInto.child))
+ }
+ }
+
+ /**
+ * Resolves output columns by input column name, adding casts if
necessary.
+ */
+ private def projectAndCastOutputColumns(
+ output: Seq[Attribute],
+ data: LogicalPlan,
+ relation: String): Seq[NamedExpression] = {
+ output.map { col =>
+ data.resolveQuoted(col.name, resolver) match {
+ case Some(inCol) if col.dataType != inCol.dataType =>
+ Alias(UpCast(inCol, col.dataType, Seq()), col.name)()
+ case Some(inCol) => inCol
+ case None =>
+ throw new AnalysisException(
+ s"Cannot resolve ${col.name} in
${data.output.mkString(",")}")
+ }
+ }
+ }
+
+ private def castAndRenameOutputColumns(
+ output: Seq[Attribute],
+ data: LogicalPlan,
+ relation: String): Seq[NamedExpression] = {
+ val outputNames = output.map(_.name)
+ // incoming expressions may not have names
+ val inputNames = data.output.flatMap(col => Option(col.name))
+ if (output.size > data.output.size) {
+ // always a problem
+ throw new AnalysisException(
+ s"""Not enough data columns to write into $relation:
+ |Data columns: ${data.output.mkString(",")}
+ |Table columns: ${outputNames.mkString(",")}""".stripMargin)
+ } else if (output.size < data.output.size) {
+ if (outputNames.toSet.subsetOf(inputNames.toSet)) {
--- End diff --
There's a slight difference if we're exposing the write-by-name feature: if
the names are a subset, then the user probably intended to write by name and we
should suggest how to do that. Given that we're not exposing write-by-name,
I'll remove it and we can add it back later.
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