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/*
* 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 scala.collection.mutable.ArrayBuffer
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.expressions.codegen.{CodegenContext, ExprCode}
import org.apache.spark.sql.catalyst.plans._
import org.apache.spark.sql.catalyst.plans.physical._
import org.apache.spark.sql.execution.{BinaryExecNode, CodegenSupport,
ExternalAppendOnlyUnsafeRowArray, RowIterator, SparkPlan}
import org.apache.spark.sql.execution.metric.{SQLMetric, SQLMetrics}
import org.apache.spark.util.collection.BitSet
/**
* Performs a sort merge join of two child relations.
*/
case class SortMergeJoinExec(
leftKeys: Seq[Expression],
rightKeys: Seq[Expression],
joinType: JoinType,
condition: Option[Expression],
left: SparkPlan,
right: SparkPlan) extends BinaryExecNode with CodegenSupport {
override lazy val metrics = Map(
"numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"))
override def output: Seq[Attribute] = {
joinType match {
case _: InnerLike =>
left.output ++ right.output
case LeftOuter =>
left.output ++ right.output.map(_.withNullability(true))
case RightOuter =>
left.output.map(_.withNullability(true)) ++ right.output
case FullOuter =>
(left.output ++ right.output).map(_.withNullability(true))
case j: ExistenceJoin =>
left.output :+ j.exists
case LeftExistence(_) =>
left.output
case x =>
throw new IllegalArgumentException(
s"${getClass.getSimpleName} should not take $x as the JoinType")
}
}
override def outputPartitioning: Partitioning = joinType match {
case _: InnerLike =>
PartitioningCollection(Seq(left.outputPartitioning, right.outputPartitioning))
// For left and right outer joins, the output is partitioned by the streamed input's join keys.
case LeftOuter => left.outputPartitioning
case RightOuter => right.outputPartitioning
case FullOuter => UnknownPartitioning(left.outputPartitioning.numPartitions)
case LeftExistence(_) => left.outputPartitioning
case x =>
throw new IllegalArgumentException(
s"${getClass.getSimpleName} should not take $x as the JoinType")
}
override def requiredChildDistribution: Seq[Distribution] =
HashClusteredDistribution(leftKeys) :: HashClusteredDistribution(rightKeys) :: Nil
override def outputOrdering: Seq[SortOrder] = joinType match {
// For inner join, orders of both sides keys should be kept.
case _: InnerLike =>
val leftKeyOrdering = getKeyOrdering(leftKeys, left.outputOrdering)
val rightKeyOrdering = getKeyOrdering(rightKeys, right.outputOrdering)
leftKeyOrdering.zip(rightKeyOrdering).map { case (lKey, rKey) =>
// Also add the right key and its `sameOrderExpressions`
SortOrder(lKey.child, Ascending, lKey.sameOrderExpressions + rKey.child ++ rKey
.sameOrderExpressions)
}
// For left and right outer joins, the output is ordered by the streamed input's join keys.
case LeftOuter => getKeyOrdering(leftKeys, left.outputOrdering)
case RightOuter => getKeyOrdering(rightKeys, right.outputOrdering)
// There are null rows in both streams, so there is no order.
case FullOuter => Nil
case LeftExistence(_) => getKeyOrdering(leftKeys, left.outputOrdering)
case x =>
throw new IllegalArgumentException(
s"${getClass.getSimpleName} should not take $x as the JoinType")
}
/**
* The utility method to get output ordering for left or right side of the join.
*
* Returns the required ordering for left or right child if childOutputOrdering does not
* satisfy the required ordering; otherwise, which means the child does not need to be sorted
* again, returns the required ordering for this child with extra "sameOrderExpressions" from
* the child's outputOrdering.
*/
private def getKeyOrdering(keys: Seq[Expression], childOutputOrdering: Seq[SortOrder])
: Seq[SortOrder] = {
val requiredOrdering = requiredOrders(keys)
if (SortOrder.orderingSatisfies(childOutputOrdering, requiredOrdering)) {
keys.zip(childOutputOrdering).map { case (key, childOrder) =>
SortOrder(key, Ascending, childOrder.sameOrderExpressions + childOrder.child - key)
}
} else {
requiredOrdering
}
}
override def requiredChildOrdering: Seq[Seq[SortOrder]] =
requiredOrders(leftKeys) :: requiredOrders(rightKeys) :: Nil
private def requiredOrders(keys: Seq[Expression]): Seq[SortOrder] = {
// This must be ascending in order to agree with the `keyOrdering` defined in `doExecute()`.
keys.map(SortOrder(_, Ascending))
}
private def createLeftKeyGenerator(): Projection =
UnsafeProjection.create(leftKeys, left.output)
private def createRightKeyGenerator(): Projection =
UnsafeProjection.create(rightKeys, right.output)
private def getSpillThreshold: Int = {
sqlContext.conf.sortMergeJoinExecBufferSpillThreshold
}
private def getInMemoryThreshold: Int = {
sqlContext.conf.sortMergeJoinExecBufferInMemoryThreshold
}
protected override def doExecute(): RDD[InternalRow] = {
val numOutputRows = longMetric("numOutputRows")
val spillThreshold = getSpillThreshold
val inMemoryThreshold = getInMemoryThreshold
left.execute().zipPartitions(right.execute()) { (leftIter, rightIter) =>
val boundCondition: (InternalRow) => Boolean = {
condition.map { cond =>
newPredicate(cond, left.output ++ right.output).eval _
}.getOrElse {
(r: InternalRow) => true
}
}
// An ordering that can be used to compare keys from both sides.
val keyOrdering = newNaturalAscendingOrdering(leftKeys.map(_.dataType))
val resultProj: InternalRow => InternalRow = UnsafeProjection.create(output, output)
joinType match {
case _: InnerLike =>
new RowIterator {
private[this] var currentLeftRow: InternalRow = _
private[this] var currentRightMatches: ExternalAppendOnlyUnsafeRowArray = _
private[this] var rightMatchesIterator: Iterator[UnsafeRow] = null
private[this] val smjScanner = new SortMergeJoinScanner(
createLeftKeyGenerator(),
createRightKeyGenerator(),
keyOrdering,
RowIterator.fromScala(leftIter),
RowIterator.fromScala(rightIter),
inMemoryThreshold,
spillThreshold
)
private[this] val joinRow = new JoinedRow
if (smjScanner.findNextInnerJoinRows()) {
currentRightMatches = smjScanner.getBufferedMatches
currentLeftRow = smjScanner.getStreamedRow
rightMatchesIterator = currentRightMatches.generateIterator()
}
override def advanceNext(): Boolean = {
while (rightMatchesIterator != null) {
if (!rightMatchesIterator.hasNext) {
if (smjScanner.findNextInnerJoinRows()) {
currentRightMatches = smjScanner.getBufferedMatches
currentLeftRow = smjScanner.getStreamedRow
rightMatchesIterator = currentRightMatches.generateIterator()
} else {
currentRightMatches = null
currentLeftRow = null
rightMatchesIterator = null
return false
}
}
joinRow(currentLeftRow, rightMatchesIterator.next())
if (boundCondition(joinRow)) {
numOutputRows += 1
return true
}
}
false
}
override def getRow: InternalRow = resultProj(joinRow)
}.toScala
case LeftOuter =>
val smjScanner = new SortMergeJoinScanner(
streamedKeyGenerator = createLeftKeyGenerator(),
bufferedKeyGenerator = createRightKeyGenerator(),
keyOrdering,
streamedIter = RowIterator.fromScala(leftIter),
bufferedIter = RowIterator.fromScala(rightIter),
inMemoryThreshold,
spillThreshold
)
val rightNullRow = new GenericInternalRow(right.output.length)
new LeftOuterIterator(
smjScanner, rightNullRow, boundCondition, resultProj, numOutputRows).toScala
case RightOuter =>
val smjScanner = new SortMergeJoinScanner(
streamedKeyGenerator = createRightKeyGenerator(),
bufferedKeyGenerator = createLeftKeyGenerator(),
keyOrdering,
streamedIter = RowIterator.fromScala(rightIter),
bufferedIter = RowIterator.fromScala(leftIter),
inMemoryThreshold,
spillThreshold
)
val leftNullRow = new GenericInternalRow(left.output.length)
new RightOuterIterator(
smjScanner, leftNullRow, boundCondition, resultProj, numOutputRows).toScala
case FullOuter =>
val leftNullRow = new GenericInternalRow(left.output.length)
val rightNullRow = new GenericInternalRow(right.output.length)
val smjScanner = new SortMergeFullOuterJoinScanner(
leftKeyGenerator = createLeftKeyGenerator(),
rightKeyGenerator = createRightKeyGenerator(),
keyOrdering,
leftIter = RowIterator.fromScala(leftIter),
rightIter = RowIterator.fromScala(rightIter),
boundCondition,
leftNullRow,
rightNullRow)
new FullOuterIterator(
smjScanner,
resultProj,
numOutputRows).toScala
case LeftSemi =>
new RowIterator {
private[this] var currentLeftRow: InternalRow = _
private[this] val smjScanner = new SortMergeJoinScanner(
createLeftKeyGenerator(),
createRightKeyGenerator(),
keyOrdering,
RowIterator.fromScala(leftIter),
RowIterator.fromScala(rightIter),
inMemoryThreshold,
spillThreshold
)
private[this] val joinRow = new JoinedRow
override def advanceNext(): Boolean = {
while (smjScanner.findNextInnerJoinRows()) {
val currentRightMatches = smjScanner.getBufferedMatches
currentLeftRow = smjScanner.getStreamedRow
if (currentRightMatches != null && currentRightMatches.length > 0) {
val rightMatchesIterator = currentRightMatches.generateIterator()
while (rightMatchesIterator.hasNext) {
joinRow(currentLeftRow, rightMatchesIterator.next())
if (boundCondition(joinRow)) {
numOutputRows += 1
return true
}
}
}
}
false
}
override def getRow: InternalRow = currentLeftRow
}.toScala
case LeftAnti =>
new RowIterator {
private[this] var currentLeftRow: InternalRow = _
private[this] val smjScanner = new SortMergeJoinScanner(
createLeftKeyGenerator(),
createRightKeyGenerator(),
keyOrdering,
RowIterator.fromScala(leftIter),
RowIterator.fromScala(rightIter),
inMemoryThreshold,
spillThreshold
)
private[this] val joinRow = new JoinedRow
override def advanceNext(): Boolean = {
while (smjScanner.findNextOuterJoinRows()) {
currentLeftRow = smjScanner.getStreamedRow
val currentRightMatches = smjScanner.getBufferedMatches
if (currentRightMatches == null || currentRightMatches.length == 0) {
numOutputRows += 1
return true
}
var found = false
val rightMatchesIterator = currentRightMatches.generateIterator()
while (!found && rightMatchesIterator.hasNext) {
joinRow(currentLeftRow, rightMatchesIterator.next())
if (boundCondition(joinRow)) {
found = true
}
}
if (!found) {
numOutputRows += 1
return true
}
}
false
}
override def getRow: InternalRow = currentLeftRow
}.toScala
case j: ExistenceJoin =>
new RowIterator {
private[this] var currentLeftRow: InternalRow = _
private[this] val result: InternalRow = new GenericInternalRow(Array[Any](null))
private[this] val smjScanner = new SortMergeJoinScanner(
createLeftKeyGenerator(),
createRightKeyGenerator(),
keyOrdering,
RowIterator.fromScala(leftIter),
RowIterator.fromScala(rightIter),
inMemoryThreshold,
spillThreshold
)
private[this] val joinRow = new JoinedRow
override def advanceNext(): Boolean = {
while (smjScanner.findNextOuterJoinRows()) {
currentLeftRow = smjScanner.getStreamedRow
val currentRightMatches = smjScanner.getBufferedMatches
var found = false
if (currentRightMatches != null && currentRightMatches.length > 0) {
val rightMatchesIterator = currentRightMatches.generateIterator()
while (!found && rightMatchesIterator.hasNext) {
joinRow(currentLeftRow, rightMatchesIterator.next())
if (boundCondition(joinRow)) {
found = true
}
}
}
result.setBoolean(0, found)
numOutputRows += 1
return true
}
false
}
override def getRow: InternalRow = resultProj(joinRow(currentLeftRow, result))
}.toScala
case x =>
throw new IllegalArgumentException(
s"SortMergeJoin should not take $x as the JoinType")
}
}
}
override def supportCodegen: Boolean = {
joinType.isInstanceOf[InnerLike]
}
override def inputRDDs(): Seq[RDD[InternalRow]] = {
left.execute() :: right.execute() :: Nil
}
private def createJoinKey(
ctx: CodegenContext,
row: String,
keys: Seq[Expression],
input: Seq[Attribute]): Seq[ExprCode] = {
ctx.INPUT_ROW = row
ctx.currentVars = null
keys.map(BindReferences.bindReference(_, input).genCode(ctx))
}
private def copyKeys(ctx: CodegenContext, vars: Seq[ExprCode]): Seq[ExprCode] = {
vars.zipWithIndex.map { case (ev, i) =>
ctx.addBufferedState(leftKeys(i).dataType, "value", ev.value)
}
}
private def genComparison(ctx: CodegenContext, a: Seq[ExprCode], b: Seq[ExprCode]): String = {
val comparisons = a.zip(b).zipWithIndex.map { case ((l, r), i) =>
s"""
|if (comp == 0) {
| comp = ${ctx.genComp(leftKeys(i).dataType, l.value, r.value)};
|}
""".stripMargin.trim
}
s"""
|comp = 0;
|${comparisons.mkString("\n")}
""".stripMargin
}
/**
* Generate a function to scan both left and right to find a match, returns the term for
* matched one row from left side and buffered rows from right side.
*/
private def genScanner(ctx: CodegenContext): (String, String) = {
// Create class member for next row from both sides.
// Inline mutable state since not many join operations in a task
val leftRow = ctx.addMutableState("InternalRow", "leftRow", forceInline = true)
val rightRow = ctx.addMutableState("InternalRow", "rightRow", forceInline = true)
// Create variables for join keys from both sides.
val leftKeyVars = createJoinKey(ctx, leftRow, leftKeys, left.output)
val leftAnyNull = leftKeyVars.map(_.isNull).mkString(" || ")
val rightKeyTmpVars = createJoinKey(ctx, rightRow, rightKeys, right.output)
val rightAnyNull = rightKeyTmpVars.map(_.isNull).mkString(" || ")
// Copy the right key as class members so they could be used in next function call.
val rightKeyVars = copyKeys(ctx, rightKeyTmpVars)
// A list to hold all matched rows from right side.
val clsName = classOf[ExternalAppendOnlyUnsafeRowArray].getName
val spillThreshold = getSpillThreshold
val inMemoryThreshold = getInMemoryThreshold
// Inline mutable state since not many join operations in a task
val matches = ctx.addMutableState(clsName, "matches",
v => s"$v = new $clsName($inMemoryThreshold, $spillThreshold);", forceInline = true)
// Copy the left keys as class members so they could be used in next function call.
val matchedKeyVars = copyKeys(ctx, leftKeyVars)
ctx.addNewFunction("findNextInnerJoinRows",
s"""
|private boolean findNextInnerJoinRows(
| scala.collection.Iterator leftIter,
| scala.collection.Iterator rightIter) {
| $leftRow = null;
| int comp = 0;
| while ($leftRow == null) {
| if (!leftIter.hasNext()) return false;
| $leftRow = (InternalRow) leftIter.next();
| ${leftKeyVars.map(_.code).mkString("\n")}
| if ($leftAnyNull) {
| $leftRow = null;
| continue;
| }
| if (!$matches.isEmpty()) {
| ${genComparison(ctx, leftKeyVars, matchedKeyVars)}
| if (comp == 0) {
| return true;
| }
| $matches.clear();
| }
|
| do {
| if ($rightRow == null) {
| if (!rightIter.hasNext()) {
| ${matchedKeyVars.map(_.code).mkString("\n")}
| return !$matches.isEmpty();
| }
| $rightRow = (InternalRow) rightIter.next();
| ${rightKeyTmpVars.map(_.code).mkString("\n")}
| if ($rightAnyNull) {
| $rightRow = null;
| continue;
| }
| ${rightKeyVars.map(_.code).mkString("\n")}
| }
| ${genComparison(ctx, leftKeyVars, rightKeyVars)}
| if (comp > 0) {
| $rightRow = null;
| } else if (comp < 0) {
| if (!$matches.isEmpty()) {
| ${matchedKeyVars.map(_.code).mkString("\n")}
| return true;
| }
| $leftRow = null;
| } else {
| $matches.add((UnsafeRow) $rightRow);
| $rightRow = null;;
| }
| } while ($leftRow != null);
| }
| return false; // unreachable
|}
""".stripMargin, inlineToOuterClass = true)
(leftRow, matches)
}
/**
* Creates variables and declarations for left part of result row.
*
* In order to defer the access after condition and also only access once in the loop,
* the variables should be declared separately from accessing the columns, we can't use the
* codegen of BoundReference here.
*/
private def createLeftVars(ctx: CodegenContext, leftRow: String): (Seq[ExprCode], Seq[String]) = {
ctx.INPUT_ROW = leftRow
left.output.zipWithIndex.map { case (a, i) =>
val value = ctx.freshName("value")
val valueCode = ctx.getValue(leftRow, a.dataType, i.toString)
val javaType = ctx.javaType(a.dataType)
val defaultValue = ctx.defaultValue(a.dataType)
if (a.nullable) {
val isNull = ctx.freshName("isNull")
val code =
s"""
|$isNull = $leftRow.isNullAt($i);
|$value = $isNull ? $defaultValue : ($valueCode);
""".stripMargin
val leftVarsDecl =
s"""
|boolean $isNull = false;
|$javaType $value = $defaultValue;
""".stripMargin
(ExprCode(code, isNull, value), leftVarsDecl)
} else {
val code = s"$value = $valueCode;"
val leftVarsDecl = s"""$javaType $value = $defaultValue;"""
(ExprCode(code, "false", value), leftVarsDecl)
}
}.unzip
}
/**
* Creates the variables for right part of result row, using BoundReference, since the right
* part are accessed inside the loop.
*/
private def createRightVar(ctx: CodegenContext, rightRow: String): Seq[ExprCode] = {
ctx.INPUT_ROW = rightRow
right.output.zipWithIndex.map { case (a, i) =>
BoundReference(i, a.dataType, a.nullable).genCode(ctx)
}
}
/**
* Splits variables based on whether it's used by condition or not, returns the code to create
* these variables before the condition and after the condition.
*
* Only a few columns are used by condition, then we can skip the accessing of those columns
* that are not used by condition also filtered out by condition.
*/
private def splitVarsByCondition(
attributes: Seq[Attribute],
variables: Seq[ExprCode]): (String, String) = {
if (condition.isDefined) {
val condRefs = condition.get.references
val (used, notUsed) = attributes.zip(variables).partition{ case (a, ev) =>
condRefs.contains(a)
}
val beforeCond = evaluateVariables(used.map(_._2))
val afterCond = evaluateVariables(notUsed.map(_._2))
(beforeCond, afterCond)
} else {
(evaluateVariables(variables), "")
}
}
override def needCopyResult: Boolean = true
override def doProduce(ctx: CodegenContext): String = {
// Inline mutable state since not many join operations in a task
val leftInput = ctx.addMutableState("scala.collection.Iterator", "leftInput",
v => s"$v = inputs[0];", forceInline = true)
val rightInput = ctx.addMutableState("scala.collection.Iterator", "rightInput",
v => s"$v = inputs[1];", forceInline = true)
val (leftRow, matches) = genScanner(ctx)
// Create variables for row from both sides.
val (leftVars, leftVarDecl) = createLeftVars(ctx, leftRow)
val rightRow = ctx.freshName("rightRow")
val rightVars = createRightVar(ctx, rightRow)
val iterator = ctx.freshName("iterator")
val numOutput = metricTerm(ctx, "numOutputRows")
val (beforeLoop, condCheck) = if (condition.isDefined) {
// Split the code of creating variables based on whether it's used by condition or not.
val loaded = ctx.freshName("loaded")
val (leftBefore, leftAfter) = splitVarsByCondition(left.output, leftVars)
val (rightBefore, rightAfter) = splitVarsByCondition(right.output, rightVars)
// Generate code for condition
ctx.currentVars = leftVars ++ rightVars
val cond = BindReferences.bindReference(condition.get, output).genCode(ctx)
// evaluate the columns those used by condition before loop
val before = s"""
|boolean $loaded = false;
|$leftBefore
""".stripMargin
val checking = s"""
|$rightBefore
|${cond.code}
|if (${cond.isNull} || !${cond.value}) continue;
|if (!$loaded) {
| $loaded = true;
| $leftAfter
|}
|$rightAfter
""".stripMargin
(before, checking)
} else {
(evaluateVariables(leftVars), "")
}
s"""
|while (findNextInnerJoinRows($leftInput, $rightInput)) {
| ${leftVarDecl.mkString("\n")}
| ${beforeLoop.trim}
| scala.collection.Iterator $iterator = $matches.generateIterator();
| while ($iterator.hasNext()) {
| InternalRow $rightRow = (InternalRow) $iterator.next();
| ${condCheck.trim}
| $numOutput.add(1);
| ${consume(ctx, leftVars ++ rightVars)}
| }
| if (shouldStop()) return;
|}
""".stripMargin
}
}
/**
* Helper class that is used to implement [[SortMergeJoinExec]].
*
* To perform an inner (outer) join, users of this class call [[findNextInnerJoinRows()]]
* ([[findNextOuterJoinRows()]]), which returns `true` if a result has been produced and `false`
* otherwise. If a result has been produced, then the caller may call [[getStreamedRow]] to return
* the matching row from the streamed input and may call [[getBufferedMatches]] to return the
* sequence of matching rows from the buffered input (in the case of an outer join, this will return
* an empty sequence if there are no matches from the buffered input). For efficiency, both of these
* methods return mutable objects which are re-used across calls to the `findNext*JoinRows()`
* methods.
*
* @param streamedKeyGenerator a projection that produces join keys from the streamed input.
* @param bufferedKeyGenerator a projection that produces join keys from the buffered input.
* @param keyOrdering an ordering which can be used to compare join keys.
* @param streamedIter an input whose rows will be streamed.
* @param bufferedIter an input whose rows will be buffered to construct sequences of rows that
* have the same join key.
* @param inMemoryThreshold Threshold for number of rows guaranteed to be held in memory by
* internal buffer
* @param spillThreshold Threshold for number of rows to be spilled by internal buffer
*/
private[joins] class SortMergeJoinScanner(
streamedKeyGenerator: Projection,
bufferedKeyGenerator: Projection,
keyOrdering: Ordering[InternalRow],
streamedIter: RowIterator,
bufferedIter: RowIterator,
inMemoryThreshold: Int,
spillThreshold: Int) {
private[this] var streamedRow: InternalRow = _
private[this] var streamedRowKey: InternalRow = _
private[this] var bufferedRow: InternalRow = _
// Note: this is guaranteed to never have any null columns:
private[this] var bufferedRowKey: InternalRow = _
/**
* The join key for the rows buffered in `bufferedMatches`, or null if `bufferedMatches` is empty
*/
private[this] var matchJoinKey: InternalRow = _
/** Buffered rows from the buffered side of the join. This is empty if there are no matches. */
private[this] val bufferedMatches =
new ExternalAppendOnlyUnsafeRowArray(inMemoryThreshold, spillThreshold)
// Initialization (note: do _not_ want to advance streamed here).
advancedBufferedToRowWithNullFreeJoinKey()
// --- Public methods ---------------------------------------------------------------------------
def getStreamedRow: InternalRow = streamedRow
def getBufferedMatches: ExternalAppendOnlyUnsafeRowArray = bufferedMatches
/**
* Advances both input iterators, stopping when we have found rows with matching join keys.
* @return true if matching rows have been found and false otherwise. If this returns true, then
* [[getStreamedRow]] and [[getBufferedMatches]] can be called to construct the join
* results.
*/
final def findNextInnerJoinRows(): Boolean = {
while (advancedStreamed() && streamedRowKey.anyNull) {
// Advance the streamed side of the join until we find the next row whose join key contains
// no nulls or we hit the end of the streamed iterator.
}
if (streamedRow == null) {
// We have consumed the entire streamed iterator, so there can be no more matches.
matchJoinKey = null
bufferedMatches.clear()
false
} else if (matchJoinKey != null && keyOrdering.compare(streamedRowKey, matchJoinKey) == 0) {
// The new streamed row has the same join key as the previous row, so return the same matches.
true
} else if (bufferedRow == null) {
// The streamed row's join key does not match the current batch of buffered rows and there are
// no more rows to read from the buffered iterator, so there can be no more matches.
matchJoinKey = null
bufferedMatches.clear()
false
} else {
// Advance both the streamed and buffered iterators to find the next pair of matching rows.
var comp = keyOrdering.compare(streamedRowKey, bufferedRowKey)
do {
if (streamedRowKey.anyNull) {
advancedStreamed()
} else {
assert(!bufferedRowKey.anyNull)
comp = keyOrdering.compare(streamedRowKey, bufferedRowKey)
if (comp > 0) advancedBufferedToRowWithNullFreeJoinKey()
else if (comp < 0) advancedStreamed()
}
} while (streamedRow != null && bufferedRow != null && comp != 0)
if (streamedRow == null || bufferedRow == null) {
// We have either hit the end of one of the iterators, so there can be no more matches.
matchJoinKey = null
bufferedMatches.clear()
false
} else {
// The streamed row's join key matches the current buffered row's join, so walk through the
// buffered iterator to buffer the rest of the matching rows.
assert(comp == 0)
bufferMatchingRows()
true
}
}
}
/**
* Advances the streamed input iterator and buffers all rows from the buffered input that
* have matching keys.
* @return true if the streamed iterator returned a row, false otherwise. If this returns true,
* then [[getStreamedRow]] and [[getBufferedMatches]] can be called to produce the outer
* join results.
*/
final def findNextOuterJoinRows(): Boolean = {
if (!advancedStreamed()) {
// We have consumed the entire streamed iterator, so there can be no more matches.
matchJoinKey = null
bufferedMatches.clear()
false
} else {
if (matchJoinKey != null && keyOrdering.compare(streamedRowKey, matchJoinKey) == 0) {
// Matches the current group, so do nothing.
} else {
// The streamed row does not match the current group.
matchJoinKey = null
bufferedMatches.clear()
if (bufferedRow != null && !streamedRowKey.anyNull) {
// The buffered iterator could still contain matching rows, so we'll need to walk through
// it until we either find matches or pass where they would be found.
var comp = 1
do {
comp = keyOrdering.compare(streamedRowKey, bufferedRowKey)
} while (comp > 0 && advancedBufferedToRowWithNullFreeJoinKey())
if (comp == 0) {
// We have found matches, so buffer them (this updates matchJoinKey)
bufferMatchingRows()
} else {
// We have overshot the position where the row would be found, hence no matches.
}
}
}
// If there is a streamed input then we always return true
true
}
}
// --- Private methods --------------------------------------------------------------------------
/**
* Advance the streamed iterator and compute the new row's join key.
* @return true if the streamed iterator returned a row and false otherwise.
*/
private def advancedStreamed(): Boolean = {
if (streamedIter.advanceNext()) {
streamedRow = streamedIter.getRow
streamedRowKey = streamedKeyGenerator(streamedRow)
true
} else {
streamedRow = null
streamedRowKey = null
false
}
}
/**
* Advance the buffered iterator until we find a row with join key that does not contain nulls.
* @return true if the buffered iterator returned a row and false otherwise.
*/
private def advancedBufferedToRowWithNullFreeJoinKey(): Boolean = {
var foundRow: Boolean = false
while (!foundRow && bufferedIter.advanceNext()) {
bufferedRow = bufferedIter.getRow
bufferedRowKey = bufferedKeyGenerator(bufferedRow)
foundRow = !bufferedRowKey.anyNull
}
if (!foundRow) {
bufferedRow = null
bufferedRowKey = null
false
} else {
true
}
}
/**
* Called when the streamed and buffered join keys match in order to buffer the matching rows.
*/
private def bufferMatchingRows(): Unit = {
assert(streamedRowKey != null)
assert(!streamedRowKey.anyNull)
assert(bufferedRowKey != null)
assert(!bufferedRowKey.anyNull)
assert(keyOrdering.compare(streamedRowKey, bufferedRowKey) == 0)
// This join key may have been produced by a mutable projection, so we need to make a copy:
matchJoinKey = streamedRowKey.copy()
bufferedMatches.clear()
do {
bufferedMatches.add(bufferedRow.asInstanceOf[UnsafeRow])
advancedBufferedToRowWithNullFreeJoinKey()
} while (bufferedRow != null && keyOrdering.compare(streamedRowKey, bufferedRowKey) == 0)
}
}
/**
* An iterator for outputting rows in left outer join.
*/
private class LeftOuterIterator(
smjScanner: SortMergeJoinScanner,
rightNullRow: InternalRow,
boundCondition: InternalRow => Boolean,
resultProj: InternalRow => InternalRow,
numOutputRows: SQLMetric)
extends OneSideOuterIterator(
smjScanner, rightNullRow, boundCondition, resultProj, numOutputRows) {
protected override def setStreamSideOutput(row: InternalRow): Unit = joinedRow.withLeft(row)
protected override def setBufferedSideOutput(row: InternalRow): Unit = joinedRow.withRight(row)
}
/**
* An iterator for outputting rows in right outer join.
*/
private class RightOuterIterator(
smjScanner: SortMergeJoinScanner,
leftNullRow: InternalRow,
boundCondition: InternalRow => Boolean,
resultProj: InternalRow => InternalRow,
numOutputRows: SQLMetric)
extends OneSideOuterIterator(smjScanner, leftNullRow, boundCondition, resultProj, numOutputRows) {
protected override def setStreamSideOutput(row: InternalRow): Unit = joinedRow.withRight(row)
protected override def setBufferedSideOutput(row: InternalRow): Unit = joinedRow.withLeft(row)
}
/**
* An abstract iterator for sharing code between [[LeftOuterIterator]] and [[RightOuterIterator]].
*
* Each [[OneSideOuterIterator]] has a streamed side and a buffered side. Each row on the
* streamed side will output 0 or many rows, one for each matching row on the buffered side.
* If there are no matches, then the buffered side of the joined output will be a null row.
*
* In left outer join, the left is the streamed side and the right is the buffered side.
* In right outer join, the right is the streamed side and the left is the buffered side.
*
* @param smjScanner a scanner that streams rows and buffers any matching rows
* @param bufferedSideNullRow the default row to return when a streamed row has no matches
* @param boundCondition an additional filter condition for buffered rows
* @param resultProj how the output should be projected
* @param numOutputRows an accumulator metric for the number of rows output
*/
private abstract class OneSideOuterIterator(
smjScanner: SortMergeJoinScanner,
bufferedSideNullRow: InternalRow,
boundCondition: InternalRow => Boolean,
resultProj: InternalRow => InternalRow,
numOutputRows: SQLMetric) extends RowIterator {
// A row to store the joined result, reused many times
protected[this] val joinedRow: JoinedRow = new JoinedRow()
// Index of the buffered rows, reset to 0 whenever we advance to a new streamed row
private[this] var rightMatchesIterator: Iterator[UnsafeRow] = null
// This iterator is initialized lazily so there should be no matches initially
assert(smjScanner.getBufferedMatches.length == 0)
// Set output methods to be overridden by subclasses
protected def setStreamSideOutput(row: InternalRow): Unit
protected def setBufferedSideOutput(row: InternalRow): Unit
/**
* Advance to the next row on the stream side and populate the buffer with matches.
* @return whether there are more rows in the stream to consume.
*/
private def advanceStream(): Boolean = {
rightMatchesIterator = null
if (smjScanner.findNextOuterJoinRows()) {
setStreamSideOutput(smjScanner.getStreamedRow)
if (smjScanner.getBufferedMatches.isEmpty) {
// There are no matching rows in the buffer, so return the null row
setBufferedSideOutput(bufferedSideNullRow)
} else {
// Find the next row in the buffer that satisfied the bound condition
if (!advanceBufferUntilBoundConditionSatisfied()) {
setBufferedSideOutput(bufferedSideNullRow)
}
}
true
} else {
// Stream has been exhausted
false
}
}
/**
* Advance to the next row in the buffer that satisfies the bound condition.
* @return whether there is such a row in the current buffer.
*/
private def advanceBufferUntilBoundConditionSatisfied(): Boolean = {
var foundMatch: Boolean = false
if (rightMatchesIterator == null) {
rightMatchesIterator = smjScanner.getBufferedMatches.generateIterator()
}
while (!foundMatch && rightMatchesIterator.hasNext) {
setBufferedSideOutput(rightMatchesIterator.next())
foundMatch = boundCondition(joinedRow)
}
foundMatch
}
override def advanceNext(): Boolean = {
val r = advanceBufferUntilBoundConditionSatisfied() || advanceStream()
if (r) numOutputRows += 1
r
}
override def getRow: InternalRow = resultProj(joinedRow)
}
private class SortMergeFullOuterJoinScanner(
leftKeyGenerator: Projection,
rightKeyGenerator: Projection,
keyOrdering: Ordering[InternalRow],
leftIter: RowIterator,
rightIter: RowIterator,
boundCondition: InternalRow => Boolean,
leftNullRow: InternalRow,
rightNullRow: InternalRow) {
private[this] val joinedRow: JoinedRow = new JoinedRow()
private[this] var leftRow: InternalRow = _
private[this] var leftRowKey: InternalRow = _
private[this] var rightRow: InternalRow = _
private[this] var rightRowKey: InternalRow = _
private[this] var leftIndex: Int = 0
private[this] var rightIndex: Int = 0
private[this] val leftMatches: ArrayBuffer[InternalRow] = new ArrayBuffer[InternalRow]
private[this] val rightMatches: ArrayBuffer[InternalRow] = new ArrayBuffer[InternalRow]
private[this] var leftMatched: BitSet = new BitSet(1)
private[this] var rightMatched: BitSet = new BitSet(1)
advancedLeft()
advancedRight()
// --- Private methods --------------------------------------------------------------------------
/**
* Advance the left iterator and compute the new row's join key.
* @return true if the left iterator returned a row and false otherwise.
*/
private def advancedLeft(): Boolean = {
if (leftIter.advanceNext()) {
leftRow = leftIter.getRow
leftRowKey = leftKeyGenerator(leftRow)
true
} else {
leftRow = null
leftRowKey = null
false
}
}
/**
* Advance the right iterator and compute the new row's join key.
* @return true if the right iterator returned a row and false otherwise.
*/
private def advancedRight(): Boolean = {
if (rightIter.advanceNext()) {
rightRow = rightIter.getRow
rightRowKey = rightKeyGenerator(rightRow)
true
} else {
rightRow = null
rightRowKey = null
false
}
}
/**
* Populate the left and right buffers with rows matching the provided key.
* This consumes rows from both iterators until their keys are different from the matching key.
*/
private def findMatchingRows(matchingKey: InternalRow): Unit = {
leftMatches.clear()
rightMatches.clear()
leftIndex = 0
rightIndex = 0
while (leftRowKey != null && keyOrdering.compare(leftRowKey, matchingKey) == 0) {
leftMatches += leftRow.copy()
advancedLeft()
}
while (rightRowKey != null && keyOrdering.compare(rightRowKey, matchingKey) == 0) {
rightMatches += rightRow.copy()
advancedRight()
}
if (leftMatches.size <= leftMatched.capacity) {
leftMatched.clearUntil(leftMatches.size)
} else {
leftMatched = new BitSet(leftMatches.size)
}
if (rightMatches.size <= rightMatched.capacity) {
rightMatched.clearUntil(rightMatches.size)
} else {
rightMatched = new BitSet(rightMatches.size)
}
}
/**
* Scan the left and right buffers for the next valid match.
*
* Note: this method mutates `joinedRow` to point to the latest matching rows in the buffers.
* If a left row has no valid matches on the right, or a right row has no valid matches on the
* left, then the row is joined with the null row and the result is considered a valid match.
*
* @return true if a valid match is found, false otherwise.
*/
private def scanNextInBuffered(): Boolean = {
while (leftIndex < leftMatches.size) {
while (rightIndex < rightMatches.size) {
joinedRow(leftMatches(leftIndex), rightMatches(rightIndex))
if (boundCondition(joinedRow)) {
leftMatched.set(leftIndex)
rightMatched.set(rightIndex)
rightIndex += 1
return true
}
rightIndex += 1
}
rightIndex = 0
if (!leftMatched.get(leftIndex)) {
// the left row has never matched any right row, join it with null row
joinedRow(leftMatches(leftIndex), rightNullRow)
leftIndex += 1
return true
}
leftIndex += 1
}
while (rightIndex < rightMatches.size) {
if (!rightMatched.get(rightIndex)) {
// the right row has never matched any left row, join it with null row
joinedRow(leftNullRow, rightMatches(rightIndex))
rightIndex += 1
return true
}
rightIndex += 1
}
// There are no more valid matches in the left and right buffers
false
}
// --- Public methods --------------------------------------------------------------------------
def getJoinedRow(): JoinedRow = joinedRow
def advanceNext(): Boolean = {
// If we already buffered some matching rows, use them directly
if (leftIndex <= leftMatches.size || rightIndex <= rightMatches.size) {
if (scanNextInBuffered()) {
return true
}
}
if (leftRow != null && (leftRowKey.anyNull || rightRow == null)) {
joinedRow(leftRow.copy(), rightNullRow)
advancedLeft()
true
} else if (rightRow != null && (rightRowKey.anyNull || leftRow == null)) {
joinedRow(leftNullRow, rightRow.copy())
advancedRight()
true
} else if (leftRow != null && rightRow != null) {
// Both rows are present and neither have null values,
// so we populate the buffers with rows matching the next key
val comp = keyOrdering.compare(leftRowKey, rightRowKey)
if (comp <= 0) {
findMatchingRows(leftRowKey.copy())
} else {
findMatchingRows(rightRowKey.copy())
}
scanNextInBuffered()
true
} else {
// Both iterators have been consumed
false
}
}
}
private class FullOuterIterator(
smjScanner: SortMergeFullOuterJoinScanner,
resultProj: InternalRow => InternalRow,
numRows: SQLMetric) extends RowIterator {
private[this] val joinedRow: JoinedRow = smjScanner.getJoinedRow()
override def advanceNext(): Boolean = {
val r = smjScanner.advanceNext()
if (r) numRows += 1
r
}
override def getRow: InternalRow = resultProj(joinedRow)
}
