Github user gatorsmile commented on a diff in the pull request:
https://github.com/apache/spark/pull/10577#discussion_r50175266
--- Diff:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/analysis/HiveTypeCoercion.scala
---
@@ -219,34 +222,62 @@ object HiveTypeCoercion {
def apply(plan: LogicalPlan): LogicalPlan = plan resolveOperators {
case p if p.analyzed => p
- case s @ SetOperation(left, right) if s.childrenResolved
- && left.output.length == right.output.length && !s.resolved =>
+ case s @ SetOperation(left, right) if s.childrenResolved &&
+ left.output.length == right.output.length && !s.resolved =>
+ val newChildren: Seq[LogicalPlan] =
buildNewChildrenWithWiderTypes(left :: right :: Nil)
+ assert(newChildren.length == 2)
+ s.makeCopy(Array(newChildren.head, newChildren.last))
- // Tracks the list of data types to widen.
- // Some(dataType) means the right-hand side and the left-hand side
have different types,
- // and there is a target type to widen both sides to.
- val targetTypes: Seq[Option[DataType]] =
left.output.zip(right.output).map {
- case (lhs, rhs) if lhs.dataType != rhs.dataType =>
- findWiderTypeForTwo(lhs.dataType, rhs.dataType)
- case other => None
- }
+ case s: Union if s.childrenResolved &&
+ s.children.forall(_.output.length ==
s.children.head.output.length) && !s.resolved =>
+ val newChildren: Seq[LogicalPlan] =
buildNewChildrenWithWiderTypes(s.children)
+ s.makeCopy(Array(newChildren))
+ }
- if (targetTypes.exists(_.isDefined)) {
- // There is at least one column to widen.
- s.makeCopy(Array(widenTypes(left, targetTypes),
widenTypes(right, targetTypes)))
- } else {
- // If we cannot find any column to widen, then just return the
original set.
- s
- }
+ /** Build new children with the widest types for each attribute among
all the children */
+ private def buildNewChildrenWithWiderTypes(children:
Seq[LogicalPlan]): Seq[LogicalPlan] = {
+ require(children.forall(_.output.length ==
children.head.output.length))
+
+ // Get a sequence of data types, each of which is the widest type of
this specific attribute
+ // in all the children
+ val targetTypes: Seq[DataType] =
+ getWidestTypes(children, attrIndex = 0, mutable.Queue[DataType]())
+
+ if (targetTypes.nonEmpty) {
+ // Add an extra Project if the targetTypes are different from the
original types.
+ children.map(widenTypes(_, targetTypes))
+ } else {
+ // Unable to find a target type to widen, then just return the
original set.
+ children
+ }
+ }
+
+ /** Get the widest type for each attribute in all the children */
+ @tailrec private def getWidestTypes(
+ children: Seq[LogicalPlan],
+ attrIndex: Int,
+ castedTypes: mutable.Queue[DataType]): Seq[DataType] = {
+ // Return the result after the widen data types have been found for
all the children
+ if (attrIndex >= children.head.output.length) return
castedTypes.toSeq
+
+ // For the attrIndex-th attribute, find the widest type
+ findWiderCommonType(children.map(_.output(attrIndex).dataType))
match {
+ // If unable to find an appropriate widen type for this column,
return an empty Seq
+ case None => Seq.empty[DataType]
+ // Otherwise, record the result in the queue and find the type for
the next column
+ case Some(widenType) =>
+ castedTypes.enqueue(widenType)
+ getWidestTypes(children, attrIndex + 1, castedTypes)
+ }
}
/** Given a plan, add an extra project on top to widen some columns'
data types. */
- private def widenTypes(plan: LogicalPlan, targetTypes:
Seq[Option[DataType]]): LogicalPlan = {
+ private def widenTypes(plan: LogicalPlan, targetTypes: Seq[DataType]):
LogicalPlan = {
val casted = plan.output.zip(targetTypes).map {
- case (e, Some(dt)) if e.dataType != dt => Alias(Cast(e, dt),
e.name)()
+ case (e, dt) if e.dataType != dt => Alias(Cast(e, dt), e.name)()
case (e, _) => e
}
- Project(casted, plan)
+ if (casted.exists(_.isInstanceOf[Alias])) Project(casted, plan) else
plan
--- End diff --
Sure, let me remove it. : )
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at infrastruct...@apache.org or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
