cloud-fan commented on a change in pull request #26437: [SPARK-29800][SQL] Plan
non-correlated Exists 's subquery in PlanSubqueries
URL: https://github.com/apache/spark/pull/26437#discussion_r362454717
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File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/optimizer/finishAnalysis.scala
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@@ -52,6 +52,20 @@ object ReplaceExpressions extends Rule[LogicalPlan] {
}
}
+/**
+ * Rewrite non correlated exists subquery to use ScalarSubquery
+ * WHERE EXISTS ( SELECT A FROM TABLE B WHERE COL1 > 10)
+ * will be rewrite to
+ * WHERE (SELECT A FROM TABLE B WHERE COL1 > 1 LIMIT 1) IS NOT NULL
+ */
+object RewriteNonCorrelatedExists extends Rule[LogicalPlan] {
+ override def apply(plan: LogicalPlan): LogicalPlan = plan
transformAllExpressions {
+ case exists: Exists if exists.children.isEmpty &&
+ !SubqueryExpression.hasInOrCorrelatedExistsSubquery(exists) =>
Review comment:
this check is not needed.
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