Github user rxin commented on a diff in the pull request:
https://github.com/apache/spark/pull/250#discussion_r11012318
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/joins.scala ---
@@ -40,33 +50,86 @@ case class SparkEquiInnerJoin(
override def requiredChildDistribution =
ClusteredDistribution(leftKeys) :: ClusteredDistribution(rightKeys) ::
Nil
+ val (buildPlan, streamedPlan) = buildSide match {
+ case BuildLeft => (left, right)
+ case BuildRight => (right, left)
+ }
+
+ val (buildKeys, streamedKeys) = buildSide match {
+ case BuildLeft => (leftKeys, rightKeys)
+ case BuildRight => (rightKeys, leftKeys)
+ }
+
def output = left.output ++ right.output
- def execute() = attachTree(this, "execute") {
- val leftWithKeys = left.execute().mapPartitions { iter =>
- val generateLeftKeys = new Projection(leftKeys, left.output)
- iter.map(row => (generateLeftKeys(row), row.copy()))
- }
+ @transient lazy val buildSideKeyGenerator = new Projection(buildKeys,
buildPlan.output)
+ @transient lazy val streamSideKeyGenerator =
+ () => new MutableProjection(streamedKeys, streamedPlan.output)
- val rightWithKeys = right.execute().mapPartitions { iter =>
- val generateRightKeys = new Projection(rightKeys, right.output)
- iter.map(row => (generateRightKeys(row), row.copy()))
- }
+ def execute() = {
- // Do the join.
- val joined =
filterNulls(leftWithKeys).joinLocally(filterNulls(rightWithKeys))
- // Drop join keys and merge input tuples.
- joined.map { case (_, (leftTuple, rightTuple)) => buildRow(leftTuple
++ rightTuple) }
- }
+ buildPlan.execute().zipPartitions(streamedPlan.execute()) {
(buildIter, streamIter) =>
+ val hashTable = new java.util.HashMap[Row, ArrayBuffer[Row]]()
+ var currentRow: Row = null
+
+ // Create a mapping of buildKeys -> rows
+ while(buildIter.hasNext) {
+ currentRow = buildIter.next()
+ val rowKey = buildSideKeyGenerator(currentRow)
+ if(!rowKey.anyNull) {
+ val existingMatchList = hashTable.get(rowKey)
+ val matchList = if (existingMatchList == null) {
+ val newMatchList = new ArrayBuffer[Row]()
+ hashTable.put(rowKey, newMatchList)
+ newMatchList
+ } else {
+ existingMatchList
+ }
+ matchList += currentRow.copy()
+ }
+ }
- /**
- * Filters any rows where the any of the join keys is null, ensuring
three-valued
- * logic for the equi-join conditions.
- */
- protected def filterNulls(rdd: RDD[(Row, Row)]) =
- rdd.filter {
- case (key: Seq[_], _) => !key.exists(_ == null)
+ new Iterator[Row] {
+ private[this] var currentRow: Row = _
+ private[this] var currentMatches: ArrayBuffer[Row] = _
+ private[this] var currentPosition: Int = -1
+
+ // Mutable per row objects.
+ private[this] val joinRow = new JoinedRow
+
+ @transient private val joinKeys = streamSideKeyGenerator()
+
+ def hasNext: Boolean =
--- End diff --
add override to hasNext and next
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