cloud-fan commented on a change in pull request #26437: [SPARK-29800][SQL] Plan
Exists 's subquery in PlanSubqueries
URL: https://github.com/apache/spark/pull/26437#discussion_r344182146
##########
File path:
sql/core/src/main/scala/org/apache/spark/sql/execution/subquery.scala
##########
@@ -171,6 +171,69 @@ case class InSubqueryExec(
}
}
+/**
+ * The physical node of exists-subquery. This is for support use exists in
join's on condition,
+ * since some join type we can't pushdown exists condition, we plan it here
+ */
+case class ExistsExec(child: Expression,
+ subQuery: String,
+ plan: BaseSubqueryExec,
+ exprId: ExprId,
+ private var resultBroadcast: Broadcast[Array[Any]] =
null)
+ extends ExecSubqueryExpression {
+
+ @transient private var result: Array[Any] = _
+
+ override def dataType: DataType = BooleanType
+ override def children: Seq[Expression] = child :: Nil
+ override def nullable: Boolean = child.nullable
+ override def toString: String = s"EXISTS ${plan.name}"
+ override def withNewPlan(plan: BaseSubqueryExec): ExistsExec = copy(plan =
plan)
+
+ override def semanticEquals(other: Expression): Boolean = other match {
+ case in: ExistsExec => child.semanticEquals(in.child) &&
plan.sameResult(in.plan)
+ case _ => false
+ }
+
+
+ def updateResult(): Unit = {
+ val rows = plan.executeCollect()
Review comment:
The reason why we don't have a physical plan for Exists is: it's not robust.
Collecting the entire result of a query plan at the driver side is very likely
to hit OOM. That's why we have to convert Exists to a join.
----------------------------------------------------------------
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:
us...@infra.apache.org
With regards,
Apache Git Services
---------------------------------------------------------------------
To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org
For additional commands, e-mail: reviews-h...@spark.apache.org
