Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/7904#discussion_r36680721
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/joins/SortMergeOuterJoin.scala
---
@@ -0,0 +1,251 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You under the Apache License, Version 2.0
+ * (the "License"); you may not use this file except in compliance with
+ * the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package org.apache.spark.sql.execution.joins
+
+import org.apache.spark.annotation.DeveloperApi
+import org.apache.spark.rdd.RDD
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.catalyst.plans.{JoinType, LeftOuter,
RightOuter}
+import org.apache.spark.sql.catalyst.plans.physical._
+import org.apache.spark.sql.execution.{BinaryNode, RowIterator, SparkPlan}
+
+/**
+ * :: DeveloperApi ::
+ * Performs an sort merge outer join of two child relations.
+ *
+ * Note: this does not support full outer join yet; see SPARK-9730 for
progress on this.
+ */
+@DeveloperApi
+case class SortMergeOuterJoin(
+ leftKeys: Seq[Expression],
+ rightKeys: Seq[Expression],
+ joinType: JoinType,
+ condition: Option[Expression],
+ left: SparkPlan,
+ right: SparkPlan) extends BinaryNode {
+
+ override def output: Seq[Attribute] = {
+ joinType match {
+ case LeftOuter =>
+ left.output ++ right.output.map(_.withNullability(true))
+ case RightOuter =>
+ left.output.map(_.withNullability(true)) ++ right.output
+ case x =>
+ throw new IllegalArgumentException(
+ s"${getClass.getSimpleName} should not take $x as the JoinType")
+ }
+ }
+
+ override def outputPartitioning: Partitioning = joinType match {
+ // For left and right outer joins, the output is partitioned by the
streamed input's join keys.
+ case LeftOuter => left.outputPartitioning
+ case RightOuter => right.outputPartitioning
+ case x =>
+ throw new IllegalArgumentException(
+ s"${getClass.getSimpleName} should not take $x as the JoinType")
+ }
+
+ override def outputOrdering: Seq[SortOrder] = joinType match {
+ // For left and right outer joins, the output is ordered by the
streamed input's join keys.
+ case LeftOuter => requiredOrders(leftKeys)
--- End diff --
Quick question about this, actually: if the join keys contain nulls then a
left or right outer join may output rows with null join keys. Does this have
any impact on the `outputOrdering` (e.g. is it safe to say that it's still
ordered by the left keys if those columns are nullable in the output)?
Presumably this is safe, since those nulls were also ordered in the input, but
I just want to confirm. @yhuai?
---
If your project is set up for it, you can reply to this email and have your
reply appear on GitHub as well. If your project does not have this feature
enabled and wishes so, or if the feature is enabled but not working, please
contact infrastructure at [email protected] or file a JIRA ticket
with INFRA.
---
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
