mgaido91 commented on a change in pull request #23531: [SPARK-24497][SQL]
Support recursive SQL query
URL: https://github.com/apache/spark/pull/23531#discussion_r251482557
##########
File path:
sql/catalyst/src/main/scala/org/apache/spark/sql/catalyst/plans/logical/basicLogicalOperators.scala
##########
@@ -47,6 +48,58 @@ case class Subquery(child: LogicalPlan) extends
OrderPreservingUnaryNode {
override def output: Seq[Attribute] = child.output
}
+/**
+ * This node defines a table that contains one ore more
[[RecursiveReference]]s as child nodes
+ * referring to this table. It can be used to define a recursive CTE query and
contains an anchor
+ * and a recursive term as children. The result of the anchor and the
repeatedly executed recursive
+ * term are combined to form the final result.
+ *
+ * @param name name of the table
+ * @param anchorTerm this child is used for initializing the query
+ * @param recursiveTerm this child is used for extending the set of results
with new rows based on
+ * the results of the previous iteration (or the anchor
in the first iteration)
+ */
+case class RecursiveTable(
+ name: String,
+ anchorTerm: LogicalPlan,
+ recursiveTerm: LogicalPlan,
+ limit: Option[Long]) extends LogicalPlan {
+ override def children: Seq[LogicalPlan] = Seq(anchorTerm, recursiveTerm)
+
+ override def output: Seq[Attribute] =
anchorTerm.output.map(_.withNullability(true))
+
+ override lazy val resolved: Boolean = {
+ val numberOfOutputMatches =
+ childrenResolved &&
+ anchorTerm.output.length > 0 &&
+ anchorTerm.output.length == recursiveTerm.output.length
+ if (numberOfOutputMatches) {
+ val typeOfOutputMatches =
anchorTerm.output.zip(recursiveTerm.output).forall {
+ case (l, r) => l.dataType.sameType(r.dataType)
+ }
+ if (!typeOfOutputMatches) {
+ throw new AnalysisException(s"Anchor term types
${anchorTerm.output.map(_.dataType)} " +
+ s"and recursive term types ${recursiveTerm.output.map(_.dataType)}
doesn't match")
+ }
+ }
+ numberOfOutputMatches
+ }
+
+ lazy val anchorResolved = anchorTerm.resolved
+}
+
+/**
+ * A This node means a reference to a recursive table in CTE definitions.
+ *
+ * @param name the name of the table it references to
+ * @param output the attributes of the recursive table
+ */
+case class RecursiveReference(name: String, output: Seq[Attribute]) extends
LeafNode {
+ override lazy val resolved = output.forall(_.resolved)
+
+ override def computeStats(): Statistics = Statistics(0)
Review comment:
No, I am not referring to this. In the other comment I mean that this PR is
heavily revisiting the lifecycle and handling of broadcasts, which is a very
sensitive topic. It'd be great if we could avoid somehow doing that, but I see
it is not easy. Just wondering i we can figure out a way which introduces less
changes there.
----------------------------------------------------------------
This is an automated message from the Apache Git Service.
To respond to the message, please log on 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]
