cloud-fan commented on a change in pull request #29587:
URL: https://github.com/apache/spark/pull/29587#discussion_r504504028
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/ResolveUnion.scala
##########
@@ -17,29 +17,190 @@
package org.apache.spark.sql.catalyst.analysis
+import scala.collection.mutable
+
import org.apache.spark.sql.AnalysisException
-import org.apache.spark.sql.catalyst.expressions.{Alias, Literal}
+import org.apache.spark.sql.catalyst.expressions._
import org.apache.spark.sql.catalyst.optimizer.CombineUnions
import org.apache.spark.sql.catalyst.plans.logical.{LogicalPlan, Project,
Union}
import org.apache.spark.sql.catalyst.rules.Rule
import org.apache.spark.sql.internal.SQLConf
+import org.apache.spark.sql.types._
import org.apache.spark.sql.util.SchemaUtils
+import org.apache.spark.unsafe.types.UTF8String
/**
* Resolves different children of Union to a common set of columns.
*/
object ResolveUnion extends Rule[LogicalPlan] {
- private def unionTwoSides(
+ /**
+ * This method sorts recursively columns in a struct expression based on
column names.
+ */
+ private def sortStructFields(expr: Expression): Expression = {
+ val existingExprs =
expr.dataType.asInstanceOf[StructType].fieldNames.zipWithIndex.map {
+ case (name, i) =>
+ val fieldExpr = GetStructField(KnownNotNull(expr), i)
+ if (fieldExpr.dataType.isInstanceOf[StructType]) {
+ (name, sortStructFields(fieldExpr))
+ } else {
+ (name, fieldExpr)
+ }
+ }.sortBy(_._1).flatMap(pair => Seq(Literal(pair._1), pair._2))
+
+ val newExpr = CreateNamedStruct(existingExprs)
+ if (expr.nullable) {
+ If(IsNull(expr), Literal(null, newExpr.dataType), newExpr)
+ } else {
+ newExpr
+ }
+ }
+
+ /**
+ * Assumes input expressions are field expression of `CreateNamedStruct`.
This method
+ * sorts the expressions based on field names.
+ */
+ private def sortFieldExprs(fieldExprs: Seq[Expression]): Seq[Expression] = {
+ fieldExprs.grouped(2).map { e =>
+ Seq(e.head, e.last)
+ }.toSeq.sortBy { pair =>
+ assert(pair.head.isInstanceOf[Literal])
+ pair.head.eval().asInstanceOf[UTF8String].toString
+ }.flatten
+ }
+
+ /**
+ * This helper method sorts fields in a `UpdateFields` expression by field
name.
+ */
+ private def sortStructFieldsInWithFields(expr: Expression): Expression =
expr transformUp {
+ case u: UpdateFields if u.resolved =>
+ u.evalExpr match {
+ case i @ If(IsNull(_), _, CreateNamedStruct(fieldExprs)) =>
+ val sorted = sortFieldExprs(fieldExprs)
+ val newStruct = CreateNamedStruct(sorted)
+ i.copy(trueValue = Literal(null, newStruct.dataType), falseValue =
newStruct)
+ case CreateNamedStruct(fieldExprs) =>
+ val sorted = sortFieldExprs(fieldExprs)
+ val newStruct = CreateNamedStruct(sorted)
+ newStruct
+ case other =>
+ throw new AnalysisException(s"`UpdateFields` has incorrect eval
expression: $other. " +
+ "Please file a bug report with this error message, stack trace,
and the query.")
+ }
+ }
+
+ def simplifyWithFields(expr: Expression): Expression = {
+ expr.transformUp {
+ case UpdateFields(UpdateFields(struct, fieldOps1), fieldOps2) =>
+ UpdateFields(struct, fieldOps1 ++ fieldOps2)
+ }
+ }
+
+ /**
+ * Adds missing fields recursively into given `col` expression, based on the
target `StructType`.
+ * This is called by `compareAndAddFields` when we find two struct columns
with same name but
+ * different nested fields. This method will find out the missing nested
fields from `col` to
+ * `target` struct and add these missing nested fields. Currently we don't
support finding out
+ * missing nested fields of struct nested in array or struct nested in map.
+ */
+ private def addFields(col: NamedExpression, target: StructType): Expression
= {
+ assert(col.dataType.isInstanceOf[StructType], "Only support StructType.")
+
+ val resolver = SQLConf.get.resolver
+ val missingFields =
+ StructType.findMissingFields(col.dataType.asInstanceOf[StructType],
target, resolver)
+
+ // We need to sort columns in result, because we might add another column
in other side.
+ // E.g., we want to union two structs "a int, b long" and "a int, c
string".
+ // If we don't sort, we will have "a int, b long, c string" and
+ // "a int, c string, b long", which are not compatible.
Review comment:
is this behavior consistent with top-level columns?
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