dilipbiswal commented on a change in pull request #24344: [SPARK-27440][SQL]
Optimize uncorrelated predicate subquery
URL: https://github.com/apache/spark/pull/24344#discussion_r285919453
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/expressions/subquery.scala
##########
@@ -93,6 +93,21 @@ object SubqueryExpression {
}.isDefined
}
+ /**
+ * Returns true when an expression contains a correlated IN or correlated
EXISTS and
+ * false otherwise. An IN is non-correlated only if the left values are
foldable
+ * and the subquery has no outer references.
+ */
+ def hasCorrelatedInOrExists(e: Expression): Boolean = {
+ e.find {
+ case InSubquery(values, ListQuery(_, children, _, _)) =>
+ values.exists(!_.foldable) || children.nonEmpty
+ case Exists(_, children, _) =>
+ children.nonEmpty
+ case _ => false
+ }.isDefined
+ }
+
Review comment:
@francis0407 Not sure what other reviewers think. I feel it would be better
to move this method into the local scope (with probably a different name) of
RewriteCorrelatedSubquery rather than keeping it as an utility function.
However, i am fine if other reviewers are okay as personally i understand what
you are trying to do here :-)
----------------------------------------------------------------
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]
