Github user JoshRosen commented on a diff in the pull request:
https://github.com/apache/spark/pull/5717#discussion_r32330049
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/joins/SortMergeJoin.scala
---
@@ -84,84 +129,164 @@ case class SortMergeJoin(
override final def next(): Row = {
if (hasNext) {
- // we are using the buffered right rows and run down left
iterator
- val joinedRow = joinRow(leftElement,
rightMatches(rightPosition))
- rightPosition += 1
- if (rightPosition >= rightMatches.size) {
- rightPosition = 0
- fetchLeft()
- if (leftElement == null || keyOrdering.compare(leftKey,
matchKey) != 0) {
- stop = false
- rightMatches = null
+ if (bufferedMatches == null || bufferedMatches.size == 0) {
+ // we just found a row with no join match and we are here to
produce a row
+ // with this row with a standard null row from the other
side.
+ if (continueStreamed) {
+ val joinedRow = smartJoinRow(streamedElement,
bufferedNullRow.copy())
+ fetchStreamed()
+ joinedRow
+ } else {
+ val joinedRow = smartJoinRow(streamedNullRow.copy(),
bufferedElement)
+ fetchBuffered()
+ joinedRow
+ }
+ } else {
+ // we are using the buffered right rows and run down left
iterator
+ val joinedRow = smartJoinRow(streamedElement,
bufferedMatches(bufferedPosition))
+ bufferedPosition += 1
+ if (bufferedPosition >= bufferedMatches.size) {
+ bufferedPosition = 0
+ if (joinType != FullOuter || secondStreamedElement ==
null) {
+ fetchStreamed()
+ if (streamedElement == null ||
keyOrdering.compare(streamedKey, matchKey) != 0) {
+ stop = false
+ bufferedMatches = null
+ }
+ } else {
+ // in FullOuter join and the first time we finish the
match buffer,
+ // we still want to generate all rows with streamed null
row and buffered
+ // rows that match the join key but not the conditions.
+ streamedElement = secondStreamedElement
+ bufferedMatches = secondBufferedMatches
+ secondStreamedElement = null
+ secondBufferedMatches = null
+ }
}
+ joinedRow
}
- joinedRow
} else {
// no more result
throw new NoSuchElementException
}
}
- private def fetchLeft() = {
- if (leftIter.hasNext) {
- leftElement = leftIter.next()
- leftKey = leftKeyGenerator(leftElement)
+ private def smartJoinRow(streamedRow: Row, bufferedRow: Row): Row
= joinType match {
+ case RightOuter => joinRow(bufferedRow, streamedRow)
+ case _ => joinRow(streamedRow, bufferedRow)
+ }
+
+ private def fetchStreamed() = {
+ if (streamedIter.hasNext) {
+ streamedElement = streamedIter.next()
+ streamedKey = streamedKeyGenerator(streamedElement)
} else {
- leftElement = null
+ streamedElement = null
}
}
- private def fetchRight() = {
- if (rightIter.hasNext) {
- rightElement = rightIter.next()
- rightKey = rightKeyGenerator(rightElement)
+ private def fetchBuffered() = {
--- End diff --
Same here: we should add `: Unit = ` if we always ignore the return value.
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