cloud-fan commented on a change in pull request #26629: [SPARK-29768][SQL]
Column pruning through nondeterministic expressions
URL: https://github.com/apache/spark/pull/26629#discussion_r350048380
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/planning/patterns.scala
##########
@@ -74,24 +95,70 @@ object PhysicalOperation extends PredicateHelper {
case other =>
(None, Nil, other, AttributeMap(Seq()))
}
+}
- private def collectAliases(fields: Seq[Expression]):
AttributeMap[Expression] =
- AttributeMap(fields.collect {
- case a: Alias => (a.toAttribute, a.child)
- })
-
- private def substitute(aliases: AttributeMap[Expression])(expr: Expression):
Expression = {
- expr.transform {
- case a @ Alias(ref: AttributeReference, name) =>
- aliases.get(ref)
- .map(Alias(_, name)(a.exprId, a.qualifier))
- .getOrElse(a)
+/**
+ * Unlike PhysicalOperation, this operation would firstly search the first
non-Project
+ * and non-Filter LogicalPlan without non-deterministic expression check and
then do that
+ * check when it back track. Once there's a failed check during backtracking,
the backtracking
+ * will return immediately.
+ */
+object ScanOperation extends OperationHelper with PredicateHelper {
- case a: AttributeReference =>
- aliases.get(a)
- .map(Alias(_, a.name)(a.exprId, a.qualifier)).getOrElse(a)
+ def unapply(plan: LogicalPlan): Option[ReturnType] = {
+ collectProjectsAndFilters(plan) match {
+ case Some((fields, filters, child, _)) =>
+ Some((fields.getOrElse(child.output), filters, child))
+ case None => None
}
}
+
+ private def hasCommonNonDeterministic(expr: Seq[Expression], aliases:
AttributeMap[Expression])
+ : Boolean = {
+ expr.exists(_.collect {
+ case Alias(ref: AttributeReference, _) if aliases.contains(ref) =>
+ aliases(ref)
+ case a: AttributeReference if aliases.contains(a) =>
+ aliases(a)
+ }.exists(!_.deterministic))
+ }
+
+ private def collectProjectsAndFilters(plan: LogicalPlan)
+ : Option[(Option[Seq[NamedExpression]], Seq[Expression], LogicalPlan,
+ AttributeMap[Expression])] =
Review comment:
it's hard to read when the type is too long to fit one line. Can we create a
type alias?
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
For queries about this service, please contact Infrastructure at:
[email protected]
With regards,
Apache Git Services
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
