Github user marmbrus commented on a diff in the pull request:
https://github.com/apache/spark/pull/1134#discussion_r14678174
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/joins.scala ---
@@ -400,3 +401,73 @@ case class BroadcastNestedLoopJoin(
streamedPlusMatches.flatMap(_._1),
sqlContext.sparkContext.makeRDD(rightOuterMatches))
}
}
+
+/**
+ * :: DeveloperApi ::
+ * In some case ,data skew happens.SkewJoin sample the table rdd to find
the largest key,
+ * then make the largest key rows as a table rdd.The left rdd will be made
leftSkewedtable
+ * rdd without the largest key and the maxkeyskewedtable rdd with the
largest key.
+ * Then,join the two table with the righttable.
+ * Finally,union the two result rdd.
+ */
+@DeveloperApi
+case class SkewJoinCartesianProduct(
+ left: SparkPlan,
+ right: SparkPlan,
+ condition: Option[Expression])(@transient sc: SparkContext) extends
BinaryNode {
+ override def output = left.output ++ right.output
+
+ @transient lazy val boundCondition =
+ InterpretedPredicate(
+ condition
+ .map(c => BindReferences.bindReference(c, left.output ++
right.output))
--- End diff --
indent only 2 from `condition`
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