spark SortMergeJoinExec 源码
spark SortMergeJoinExec 代码
文件路径：/sql/core/src/main/scala/org/apache/spark/sql/execution/joins/SortMergeJoinExec.scala
/*
* 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.TaskContext
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.BindReferences.bindReferences
import org.apache.spark.sql.catalyst.expressions.codegen._
import org.apache.spark.sql.catalyst.expressions.codegen.Block._
import org.apache.spark.sql.catalyst.plans._
import org.apache.spark.sql.execution._
import org.apache.spark.sql.execution.metric.{SQLMetric, SQLMetrics}
import org.apache.spark.sql.internal.SQLConf
import org.apache.spark.sql.types.BooleanType
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,
isSkewJoin: Boolean = false) extends ShuffledJoin {
override lazy val metrics = Map(
"numOutputRows" -> SQLMetrics.createMetric(sparkContext, "number of output rows"),
"spillSize" -> SQLMetrics.createSizeMetric(sparkContext, "spill size"))
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 expressions from right side sort order
val sameOrderExpressions = ExpressionSet(lKey.sameOrderExpressions ++ rKey.children)
SortOrder(lKey.child, Ascending, sameOrderExpressions.toSeq)
}
// 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) =>
val sameOrderExpressionsSet = ExpressionSet(childOrder.children) - key
SortOrder(key, Ascending, sameOrderExpressionsSet.toSeq)
}
} 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 = {
conf.sortMergeJoinExecBufferSpillThreshold
}
// Flag to only buffer first matched row, to avoid buffering unnecessary rows.
private val onlyBufferFirstMatchedRow = (joinType, condition) match {
case (LeftExistence(_), None) => true
case _ => false
}
private def getInMemoryThreshold: Int = {
if (onlyBufferFirstMatchedRow) {
1
} else {
conf.sortMergeJoinExecBufferInMemoryThreshold
}
}
protected override def doExecute(): RDD[InternalRow] = {
val numOutputRows = longMetric("numOutputRows")
val spillSize = longMetric("spillSize")
val spillThreshold = getSpillThreshold
val inMemoryThreshold = getInMemoryThreshold
left.execute().zipPartitions(right.execute()) { (leftIter, rightIter) =>
val boundCondition: (InternalRow) => Boolean = {
condition.map { cond =>
Predicate.create(cond, left.output ++ right.output).eval _
}.getOrElse {
(r: InternalRow) => true
}
}
// An ordering that can be used to compare keys from both sides.
val keyOrdering = RowOrdering.createNaturalAscendingOrdering(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,
spillSize,
cleanupResources
)
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,
spillSize,
cleanupResources
)
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,
spillSize,
cleanupResources
)
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,
spillSize,
cleanupResources,
onlyBufferFirstMatchedRow
)
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,
spillSize,
cleanupResources,
onlyBufferFirstMatchedRow
)
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,
spillSize,
cleanupResources,
onlyBufferFirstMatchedRow
)
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")
}
}
}
private lazy val ((streamedPlan, streamedKeys), (bufferedPlan, bufferedKeys)) = joinType match {
case _: InnerLike | LeftOuter | FullOuter | LeftExistence(_) =>
((left, leftKeys), (right, rightKeys))
case RightOuter => ((right, rightKeys), (left, leftKeys))
case x =>
throw new IllegalArgumentException(
s"SortMergeJoin.streamedPlan/bufferedPlan should not take $x as the JoinType")
}
private lazy val streamedOutput = streamedPlan.output
private lazy val bufferedOutput = bufferedPlan.output
override def supportCodegen: Boolean = joinType match {
case FullOuter => conf.getConf(SQLConf.ENABLE_FULL_OUTER_SORT_MERGE_JOIN_CODEGEN)
case _: ExistenceJoin => conf.getConf(SQLConf.ENABLE_EXISTENCE_SORT_MERGE_JOIN_CODEGEN)
case _ => true
}
override def inputRDDs(): Seq[RDD[InternalRow]] = {
streamedPlan.execute() :: bufferedPlan.execute() :: Nil
}
private def createJoinKey(
ctx: CodegenContext,
row: String,
keys: Seq[Expression],
input: Seq[Attribute]): Seq[ExprCode] = {
ctx.INPUT_ROW = row
ctx.currentVars = null
bindReferences(keys, input).map(_.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 sides to find a match, returns:
* 1. the function name
* 2. the term for matched one row from streamed side
* 3. the term for buffered rows from buffered side
*/
private def genScanner(ctx: CodegenContext): (String, String, String) = {
// Create class member for next row from both sides.
// Inline mutable state since not many join operations in a task
val streamedRow = ctx.addMutableState("InternalRow", "streamedRow", forceInline = true)
val bufferedRow = ctx.addMutableState("InternalRow", "bufferedRow", forceInline = true)
// Create variables for join keys from both sides.
val streamedKeyVars = createJoinKey(ctx, streamedRow, streamedKeys, streamedOutput)
val streamedAnyNull = streamedKeyVars.map(_.isNull).mkString(" || ")
val bufferedKeyTmpVars = createJoinKey(ctx, bufferedRow, bufferedKeys, bufferedOutput)
val bufferedAnyNull = bufferedKeyTmpVars.map(_.isNull).mkString(" || ")
// Copy the buffered key as class members so they could be used in next function call.
val bufferedKeyVars = copyKeys(ctx, bufferedKeyTmpVars)
// A list to hold all matched rows from buffered 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, $spillThreshold);", forceInline = true)
// Copy the streamed keys as class members so they could be used in next function call.
val matchedKeyVars = copyKeys(ctx, streamedKeyVars)
// Handle the case when streamed rows has any NULL keys.
val handleStreamedAnyNull = joinType match {
case _: InnerLike | LeftSemi =>
// Skip streamed row.
s"""
|$streamedRow = null;
|continue;
""".stripMargin
case LeftOuter | RightOuter | LeftAnti | ExistenceJoin(_) =>
// Eagerly return streamed row. Only call `matches.clear()` when `matches.isEmpty()` is
// false, to reduce unnecessary computation.
s"""
|if (!$matches.isEmpty()) {
| $matches.clear();
|}
|return false;
""".stripMargin
case x =>
throw new IllegalArgumentException(
s"SortMergeJoin.genScanner should not take $x as the JoinType")
}
// Handle the case when streamed keys has no match with buffered side.
val handleStreamedWithoutMatch = joinType match {
case _: InnerLike | LeftSemi =>
// Skip streamed row.
s"$streamedRow = null;"
case LeftOuter | RightOuter | LeftAnti | ExistenceJoin(_) =>
// Eagerly return with streamed row.
"return false;"
case x =>
throw new IllegalArgumentException(
s"SortMergeJoin.genScanner should not take $x as the JoinType")
}
val addRowToBuffer =
if (onlyBufferFirstMatchedRow) {
s"""
|if ($matches.isEmpty()) {
| $matches.add((UnsafeRow) $bufferedRow);
|}
""".stripMargin
} else {
s"$matches.add((UnsafeRow) $bufferedRow);"
}
// Generate a function to scan both streamed and buffered sides to find a match.
// Return whether a match is found.
//
// `streamedIter`: the iterator for streamed side.
// `bufferedIter`: the iterator for buffered side.
// `streamedRow`: the current row from streamed side.
// When `streamedIter` is empty, `streamedRow` is null.
// `matches`: the rows from buffered side already matched with `streamedRow`.
// `matches` is buffered and reused for all `streamedRow`s having same join keys.
// If there is no match with `streamedRow`, `matches` is empty.
// `bufferedRow`: the current matched row from buffered side.
//
// The function has the following step:
// - Step 1: Find the next `streamedRow` with non-null join keys.
// For `streamedRow` with null join keys (`handleStreamedAnyNull`):
// 1. Inner and Left Semi join: skip the row. `matches` will be cleared later when
// hitting the next `streamedRow` with non-null join
// keys.
// 2. Left/Right Outer, Left Anti and Existence join: clear the previous `matches`
// if needed, keep the row, and
// return false.
//
// - Step 2: Find the `matches` from buffered side having same join keys with `streamedRow`.
// Clear `matches` if we hit a new `streamedRow`, as we need to find new matches.
// Use `bufferedRow` to iterate buffered side to put all matched rows into
// `matches` (`addRowToBuffer`). Return true when getting all matched rows.
// For `streamedRow` without `matches` (`handleStreamedWithoutMatch`):
// 1. Inner and Left Semi join: skip the row.
// 2. Left/Right Outer, Left Anti and Existence join: keep the row and return false
// (with `matches` being empty).
val findNextJoinRowsFuncName = ctx.freshName("findNextJoinRows")
ctx.addNewFunction(findNextJoinRowsFuncName,
s"""
|private boolean $findNextJoinRowsFuncName(
| scala.collection.Iterator streamedIter,
| scala.collection.Iterator bufferedIter) {
| $streamedRow = null;
| int comp = 0;
| while ($streamedRow == null) {
| if (!streamedIter.hasNext()) return false;
| $streamedRow = (InternalRow) streamedIter.next();
| ${streamedKeyVars.map(_.code).mkString("\n")}
| if ($streamedAnyNull) {
| $handleStreamedAnyNull
| }
| if (!$matches.isEmpty()) {
| ${genComparison(ctx, streamedKeyVars, matchedKeyVars)}
| if (comp == 0) {
| return true;
| }
| $matches.clear();
| }
|
| do {
| if ($bufferedRow == null) {
| if (!bufferedIter.hasNext()) {
| ${matchedKeyVars.map(_.code).mkString("\n")}
| return !$matches.isEmpty();
| }
| $bufferedRow = (InternalRow) bufferedIter.next();
| ${bufferedKeyTmpVars.map(_.code).mkString("\n")}
| if ($bufferedAnyNull) {
| $bufferedRow = null;
| continue;
| }
| ${bufferedKeyVars.map(_.code).mkString("\n")}
| }
| ${genComparison(ctx, streamedKeyVars, bufferedKeyVars)}
| if (comp > 0) {
| $bufferedRow = null;
| } else if (comp < 0) {
| if (!$matches.isEmpty()) {
| ${matchedKeyVars.map(_.code).mkString("\n")}
| return true;
| } else {
| $handleStreamedWithoutMatch
| }
| } else {
| $addRowToBuffer
| $bufferedRow = null;
| }
| } while ($streamedRow != null);
| }
| return false; // unreachable
|}
""".stripMargin, inlineToOuterClass = true)
(findNextJoinRowsFuncName, streamedRow, matches)
}
/**
* Creates variables and declarations for streamed 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 createStreamedVars(
ctx: CodegenContext,
streamedRow: String): (Seq[ExprCode], Seq[String]) = {
ctx.INPUT_ROW = streamedRow
streamedPlan.output.zipWithIndex.map { case (a, i) =>
val value = ctx.freshName("value")
val valueCode = CodeGenerator.getValue(streamedRow, a.dataType, i.toString)
val javaType = CodeGenerator.javaType(a.dataType)
val defaultValue = CodeGenerator.defaultValue(a.dataType)
if (a.nullable) {
val isNull = ctx.freshName("isNull")
val code =
code"""
|$isNull = $streamedRow.isNullAt($i);
|$value = $isNull ? $defaultValue : ($valueCode);
""".stripMargin
val streamedVarsDecl =
s"""
|boolean $isNull = false;
|$javaType $value = $defaultValue;
""".stripMargin
(ExprCode(code, JavaCode.isNullVariable(isNull), JavaCode.variable(value, a.dataType)),
streamedVarsDecl)
} else {
val code = code"$value = $valueCode;"
val streamedVarsDecl = s"""$javaType $value = $defaultValue;"""
(ExprCode(code, FalseLiteral, JavaCode.variable(value, a.dataType)), streamedVarsDecl)
}
}.unzip
}
/**
* Splits variables based on whether it's used by condition or not, returns the code to create
* these variables before the condition and after the condition.
*
* Only a few columns are used by condition, then we can skip the accessing of those columns
* that are not used by condition also filtered out by condition.
*/
private def splitVarsByCondition(
attributes: Seq[Attribute],
variables: Seq[ExprCode]): (String, String) = {
if (condition.isDefined) {
val condRefs = condition.get.references
val (used, notUsed) = attributes.zip(variables).partition{ case (a, ev) =>
condRefs.contains(a)
}
val beforeCond = evaluateVariables(used.map(_._2))
val afterCond = evaluateVariables(notUsed.map(_._2))
(beforeCond, afterCond)
} else {
(evaluateVariables(variables), "")
}
}
override def needCopyResult: Boolean = true
/**
* This is called by generated Java class, should be public.
*/
def getTaskContext(): TaskContext = {
TaskContext.get()
}
override def doProduce(ctx: CodegenContext): String = {
// Specialize `doProduce` code for full outer join, because full outer join needs to
// buffer both sides of join.
if (joinType == FullOuter) {
return codegenFullOuter(ctx)
}
// Inline mutable state since not many join operations in a task
val streamedInput = ctx.addMutableState("scala.collection.Iterator", "streamedInput",
v => s"$v = inputs[0];", forceInline = true)
val bufferedInput = ctx.addMutableState("scala.collection.Iterator", "bufferedInput",
v => s"$v = inputs[1];", forceInline = true)
val (findNextJoinRowsFuncName, streamedRow, matches) = genScanner(ctx)
// Create variables for row from both sides.
val (streamedVars, streamedVarDecl) = createStreamedVars(ctx, streamedRow)
val bufferedRow = ctx.freshName("bufferedRow")
val setDefaultValue = joinType == LeftOuter || joinType == RightOuter
val bufferedVars = genOneSideJoinVars(ctx, bufferedRow, bufferedPlan, setDefaultValue)
// Create variable name for Existence join.
val existsVar = joinType match {
case ExistenceJoin(_) => Some(ctx.freshName("exists"))
case _ => None
}
val iterator = ctx.freshName("iterator")
val numOutput = metricTerm(ctx, "numOutputRows")
val resultVars = joinType match {
case _: InnerLike | LeftOuter =>
streamedVars ++ bufferedVars
case RightOuter =>
bufferedVars ++ streamedVars
case LeftSemi | LeftAnti =>
streamedVars
case ExistenceJoin(_) =>
streamedVars ++ Seq(ExprCode.forNonNullValue(
JavaCode.variable(existsVar.get, BooleanType)))
case x =>
throw new IllegalArgumentException(
s"SortMergeJoin.doProduce should not take $x as the JoinType")
}
val (streamedBeforeLoop, condCheck, loadStreamed) = 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 (streamedBefore, streamedAfter) = splitVarsByCondition(streamedOutput, streamedVars)
val (bufferedBefore, bufferedAfter) = splitVarsByCondition(bufferedOutput, bufferedVars)
// Generate code for condition
ctx.currentVars = streamedVars ++ bufferedVars
val cond = BindReferences.bindReference(
condition.get, streamedPlan.output ++ bufferedPlan.output).genCode(ctx)
// Evaluate the columns those used by condition before loop
val before = joinType match {
case LeftAnti =>
// No need to initialize `loaded` variable for Left Anti join.
streamedBefore.trim
case _ =>
s"""
|boolean $loaded = false;
|$streamedBefore
""".stripMargin
}
val loadStreamedAfterCondition = joinType match {
case LeftAnti =>
// No need to evaluate columns not used by condition from streamed side, as for Left Anti
// join, streamed row with match is not outputted.
""
case _ =>
s"""
|if (!$loaded) {
| $loaded = true;
| $streamedAfter
|}
""".stripMargin
}
val loadBufferedAfterCondition = joinType match {
case LeftExistence(_) =>
// No need to evaluate columns not used by condition from buffered side
""
case _ => bufferedAfter
}
val checking =
s"""
|$bufferedBefore
|if ($bufferedRow != null) {
| ${cond.code}
| if (${cond.isNull} || !${cond.value}) {
| continue;
| }
|}
|$loadStreamedAfterCondition
|$loadBufferedAfterCondition
""".stripMargin
(before, checking.trim, streamedAfter.trim)
} else {
(evaluateVariables(streamedVars), "", "")
}
val beforeLoop =
s"""
|${streamedVarDecl.mkString("\n")}
|${streamedBeforeLoop.trim}
|scala.collection.Iterator<UnsafeRow> $iterator = $matches.generateIterator();
""".stripMargin
val outputRow =
s"""
|$numOutput.add(1);
|${consume(ctx, resultVars)}
""".stripMargin
val findNextJoinRows = s"$findNextJoinRowsFuncName($streamedInput, $bufferedInput)"
val thisPlan = ctx.addReferenceObj("plan", this)
val eagerCleanup = s"$thisPlan.cleanupResources();"
val doJoin = joinType match {
case _: InnerLike =>
codegenInner(findNextJoinRows, beforeLoop, iterator, bufferedRow, condCheck, outputRow,
eagerCleanup)
case LeftOuter | RightOuter =>
codegenOuter(streamedInput, findNextJoinRows, beforeLoop, iterator, bufferedRow, condCheck,
ctx.freshName("hasOutputRow"), outputRow, eagerCleanup)
case LeftSemi =>
codegenSemi(findNextJoinRows, beforeLoop, iterator, bufferedRow, condCheck,
ctx.freshName("hasOutputRow"), outputRow, eagerCleanup)
case LeftAnti =>
codegenAnti(streamedInput, findNextJoinRows, beforeLoop, iterator, bufferedRow, condCheck,
loadStreamed, ctx.freshName("hasMatchedRow"), outputRow, eagerCleanup)
case ExistenceJoin(_) =>
codegenExistence(streamedInput, findNextJoinRows, beforeLoop, iterator, bufferedRow,
condCheck, loadStreamed, existsVar.get, outputRow, eagerCleanup)
case x =>
throw new IllegalArgumentException(
s"SortMergeJoin.doProduce should not take $x as the JoinType")
}
val initJoin = ctx.addMutableState(CodeGenerator.JAVA_BOOLEAN, "initJoin")
val addHookToRecordMetrics =
s"""
|$thisPlan.getTaskContext().addTaskCompletionListener(
| new org.apache.spark.util.TaskCompletionListener() {
| @Override
| public void onTaskCompletion(org.apache.spark.TaskContext context) {
| ${metricTerm(ctx, "spillSize")}.add($matches.spillSize());
| }
|});
""".stripMargin
s"""
|if (!$initJoin) {
| $initJoin = true;
| $addHookToRecordMetrics
|}
|$doJoin
""".stripMargin
}
/**
* Generates the code for Inner join.
*/
private def codegenInner(
findNextJoinRows: String,
beforeLoop: String,
matchIterator: String,
bufferedRow: String,
conditionCheck: String,
outputRow: String,
eagerCleanup: String): String = {
s"""
|while ($findNextJoinRows) {
| $beforeLoop
| while ($matchIterator.hasNext()) {
| InternalRow $bufferedRow = (InternalRow) $matchIterator.next();
| $conditionCheck
| $outputRow
| }
| if (shouldStop()) return;
|}
|$eagerCleanup
""".stripMargin
}
/**
* Generates the code for Left or Right Outer join.
*/
private def codegenOuter(
streamedInput: String,
findNextJoinRows: String,
beforeLoop: String,
matchIterator: String,
bufferedRow: String,
conditionCheck: String,
hasOutputRow: String,
outputRow: String,
eagerCleanup: String): String = {
s"""
|while ($streamedInput.hasNext()) {
| $findNextJoinRows;
| $beforeLoop
| boolean $hasOutputRow = false;
|
| // the last iteration of this loop is to emit an empty row if there is no matched rows.
| while ($matchIterator.hasNext() || !$hasOutputRow) {
| InternalRow $bufferedRow = $matchIterator.hasNext() ?
| (InternalRow) $matchIterator.next() : null;
| $conditionCheck
| $hasOutputRow = true;
| $outputRow
| }
| if (shouldStop()) return;
|}
|$eagerCleanup
""".stripMargin
}
/**
* Generates the code for Left Semi join.
*/
private def codegenSemi(
findNextJoinRows: String,
beforeLoop: String,
matchIterator: String,
bufferedRow: String,
conditionCheck: String,
hasOutputRow: String,
outputRow: String,
eagerCleanup: String): String = {
s"""
|while ($findNextJoinRows) {
| $beforeLoop
| boolean $hasOutputRow = false;
|
| while (!$hasOutputRow && $matchIterator.hasNext()) {
| InternalRow $bufferedRow = (InternalRow) $matchIterator.next();
| $conditionCheck
| $hasOutputRow = true;
| $outputRow
| }
| if (shouldStop()) return;
|}
|$eagerCleanup
""".stripMargin
}
/**
* Generates the code for Left Anti join.
*/
private def codegenAnti(
streamedInput: String,
findNextJoinRows: String,
beforeLoop: String,
matchIterator: String,
bufferedRow: String,
conditionCheck: String,
loadStreamed: String,
hasMatchedRow: String,
outputRow: String,
eagerCleanup: String): String = {
s"""
|while ($streamedInput.hasNext()) {
| $findNextJoinRows;
| $beforeLoop
| boolean $hasMatchedRow = false;
|
| while (!$hasMatchedRow && $matchIterator.hasNext()) {
| InternalRow $bufferedRow = (InternalRow) $matchIterator.next();
| $conditionCheck
| $hasMatchedRow = true;
| }
|
| if (!$hasMatchedRow) {
| // load all values of streamed row, because the values not in join condition are not
| // loaded yet.
| $loadStreamed
| $outputRow
| }
| if (shouldStop()) return;
|}
|$eagerCleanup
""".stripMargin
}
/**
* Generates the code for Existence join.
*/
private def codegenExistence(
streamedInput: String,
findNextJoinRows: String,
beforeLoop: String,
matchIterator: String,
bufferedRow: String,
conditionCheck: String,
loadStreamed: String,
exists: String,
outputRow: String,
eagerCleanup: String): String = {
s"""
|while ($streamedInput.hasNext()) {
| $findNextJoinRows;
| $beforeLoop
| boolean $exists = false;
|
| while (!$exists && $matchIterator.hasNext()) {
| InternalRow $bufferedRow = (InternalRow) $matchIterator.next();
| $conditionCheck
| $exists = true;
| }
|
| if (!$exists) {
| // load all values of streamed row, because the values not in join condition are not
| // loaded yet.
| $loadStreamed
| }
| $outputRow
|
| if (shouldStop()) return;
|}
|$eagerCleanup
""".stripMargin
}
/**
* Generates the code for Full Outer join.
*/
private def codegenFullOuter(ctx: CodegenContext): String = {
// Inline mutable state since not many join operations in a task.
// Create class member for input iterator from both sides.
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)
// Create class member for next input row from both sides.
val leftInputRow = ctx.addMutableState("InternalRow", "leftInputRow", forceInline = true)
val rightInputRow = ctx.addMutableState("InternalRow", "rightInputRow", forceInline = true)
// Create variables for join keys from both sides.
val leftKeyVars = createJoinKey(ctx, leftInputRow, leftKeys, left.output)
val leftAnyNull = leftKeyVars.map(_.isNull).mkString(" || ")
val rightKeyVars = createJoinKey(ctx, rightInputRow, rightKeys, right.output)
val rightAnyNull = rightKeyVars.map(_.isNull).mkString(" || ")
val matchedKeyVars = copyKeys(ctx, leftKeyVars)
val leftMatchedKeyVars = createJoinKey(ctx, leftInputRow, leftKeys, left.output)
val rightMatchedKeyVars = createJoinKey(ctx, rightInputRow, rightKeys, right.output)
// Create class member for next output row from both sides.
val leftOutputRow = ctx.addMutableState("InternalRow", "leftOutputRow", forceInline = true)
val rightOutputRow = ctx.addMutableState("InternalRow", "rightOutputRow", forceInline = true)
// Create class member for buffers of rows with same join keys from both sides.
val bufferClsName = "java.util.ArrayList<InternalRow>"
val leftBuffer = ctx.addMutableState(bufferClsName, "leftBuffer",
v => s"$v = new $bufferClsName();", forceInline = true)
val rightBuffer = ctx.addMutableState(bufferClsName, "rightBuffer",
v => s"$v = new $bufferClsName();", forceInline = true)
val matchedClsName = classOf[BitSet].getName
val leftMatched = ctx.addMutableState(matchedClsName, "leftMatched",
v => s"$v = new $matchedClsName(1);", forceInline = true)
val rightMatched = ctx.addMutableState(matchedClsName, "rightMatched",
v => s"$v = new $matchedClsName(1);", forceInline = true)
val leftIndex = ctx.freshName("leftIndex")
val rightIndex = ctx.freshName("rightIndex")
// Generate code for join condition
val leftResultVars = genOneSideJoinVars(
ctx, leftOutputRow, left, setDefaultValue = true)
val rightResultVars = genOneSideJoinVars(
ctx, rightOutputRow, right, setDefaultValue = true)
val resultVars = leftResultVars ++ rightResultVars
val (_, conditionCheck, _) =
getJoinCondition(ctx, leftResultVars, left, right, Some(rightOutputRow))
// Generate code for result output in separate function, as we need to output result from
// multiple places in join code.
val consumeFullOuterJoinRow = ctx.freshName("consumeFullOuterJoinRow")
ctx.addNewFunction(consumeFullOuterJoinRow,
s"""
|private void $consumeFullOuterJoinRow() throws java.io.IOException {
| ${metricTerm(ctx, "numOutputRows")}.add(1);
| ${consume(ctx, resultVars)}
|}
""".stripMargin)
// Handle the case when input row has no match.
val outputLeftNoMatch =
s"""
|$leftOutputRow = $leftInputRow;
|$rightOutputRow = null;
|$leftInputRow = null;
|$consumeFullOuterJoinRow();
""".stripMargin
val outputRightNoMatch =
s"""
|$rightOutputRow = $rightInputRow;
|$leftOutputRow = null;
|$rightInputRow = null;
|$consumeFullOuterJoinRow();
""".stripMargin
// Generate a function to scan both sides to find rows with matched join keys.
// The matched rows from both sides are copied in buffers separately. This function assumes
// either non-empty `leftIter` and `rightIter`, or non-null `leftInputRow` and `rightInputRow`.
//
// The function has the following steps:
// - Step 1: Find the next `leftInputRow` and `rightInputRow` with non-null join keys.
// Output row with null join keys (`outputLeftNoMatch` and `outputRightNoMatch`).
//
// - Step 2: Compare and find next same join keys from between `leftInputRow` and
// `rightInputRow`.
// Output row with smaller join keys (`outputLeftNoMatch` and `outputRightNoMatch`).
//
// - Step 3: Buffer rows with same join keys from both sides into `leftBuffer` and
// `rightBuffer`. Reset bit sets for both buffers accordingly (`leftMatched` and
// `rightMatched`).
val findNextJoinRowsFuncName = ctx.freshName("findNextJoinRows")
ctx.addNewFunction(findNextJoinRowsFuncName,
s"""
|private void $findNextJoinRowsFuncName(
| scala.collection.Iterator leftIter,
| scala.collection.Iterator rightIter) throws java.io.IOException {
| int comp = 0;
| $leftBuffer.clear();
| $rightBuffer.clear();
|
| if ($leftInputRow == null) {
| $leftInputRow = (InternalRow) leftIter.next();
| }
| if ($rightInputRow == null) {
| $rightInputRow = (InternalRow) rightIter.next();
| }
|
| ${leftKeyVars.map(_.code).mkString("\n")}
| if ($leftAnyNull) {
| // The left row join key is null, join it with null row
| $outputLeftNoMatch
| return;
| }
|
| ${rightKeyVars.map(_.code).mkString("\n")}
| if ($rightAnyNull) {
| // The right row join key is null, join it with null row
| $outputRightNoMatch
| return;
| }
|
| ${genComparison(ctx, leftKeyVars, rightKeyVars)}
| if (comp < 0) {
| // The left row join key is smaller, join it with null row
| $outputLeftNoMatch
| return;
| } else if (comp > 0) {
| // The right row join key is smaller, join it with null row
| $outputRightNoMatch
| return;
| }
|
| ${matchedKeyVars.map(_.code).mkString("\n")}
| $leftBuffer.add($leftInputRow.copy());
| $rightBuffer.add($rightInputRow.copy());
| $leftInputRow = null;
| $rightInputRow = null;
|
| // Buffer rows from both sides with same join key
| while (leftIter.hasNext()) {
| $leftInputRow = (InternalRow) leftIter.next();
| ${leftMatchedKeyVars.map(_.code).mkString("\n")}
| ${genComparison(ctx, leftMatchedKeyVars, matchedKeyVars)}
| if (comp == 0) {
|
| $leftBuffer.add($leftInputRow.copy());
| $leftInputRow = null;
| } else {
| break;
| }
| }
| while (rightIter.hasNext()) {
| $rightInputRow = (InternalRow) rightIter.next();
| ${rightMatchedKeyVars.map(_.code).mkString("\n")}
| ${genComparison(ctx, rightMatchedKeyVars, matchedKeyVars)}
| if (comp == 0) {
| $rightBuffer.add($rightInputRow.copy());
| $rightInputRow = null;
| } else {
| break;
| }
| }
|
| // Reset bit sets of buffers accordingly
| if ($leftBuffer.size() <= $leftMatched.capacity()) {
| $leftMatched.clearUntil($leftBuffer.size());
| } else {
| $leftMatched = new $matchedClsName($leftBuffer.size());
| }
| if ($rightBuffer.size() <= $rightMatched.capacity()) {
| $rightMatched.clearUntil($rightBuffer.size());
| } else {
| $rightMatched = new $matchedClsName($rightBuffer.size());
| }
|}
""".stripMargin)
// Scan the left and right buffers to find all matched rows.
val matchRowsInBuffer =
s"""
|int $leftIndex;
|int $rightIndex;
|
|for ($leftIndex = 0; $leftIndex < $leftBuffer.size(); $leftIndex++) {
| $leftOutputRow = (InternalRow) $leftBuffer.get($leftIndex);
| for ($rightIndex = 0; $rightIndex < $rightBuffer.size(); $rightIndex++) {
| $rightOutputRow = (InternalRow) $rightBuffer.get($rightIndex);
| $conditionCheck {
| $consumeFullOuterJoinRow();
| $leftMatched.set($leftIndex);
| $rightMatched.set($rightIndex);
| }
| }
|
| if (!$leftMatched.get($leftIndex)) {
|
| $rightOutputRow = null;
| $consumeFullOuterJoinRow();
| }
|}
|
|$leftOutputRow = null;
|for ($rightIndex = 0; $rightIndex < $rightBuffer.size(); $rightIndex++) {
| if (!$rightMatched.get($rightIndex)) {
| // The right row has never matched any left row, join it with null row
| $rightOutputRow = (InternalRow) $rightBuffer.get($rightIndex);
| $consumeFullOuterJoinRow();
| }
|}
""".stripMargin
s"""
|while (($leftInputRow != null || $leftInput.hasNext()) &&
| ($rightInputRow != null || $rightInput.hasNext())) {
| $findNextJoinRowsFuncName($leftInput, $rightInput);
| $matchRowsInBuffer
| if (shouldStop()) return;
|}
|
|// The right iterator has no more rows, join left row with null
|while ($leftInputRow != null || $leftInput.hasNext()) {
| if ($leftInputRow == null) {
| $leftInputRow = (InternalRow) $leftInput.next();
| }
| $outputLeftNoMatch
| if (shouldStop()) return;
|}
|
|// The left iterator has no more rows, join right row with null
|while ($rightInputRow != null || $rightInput.hasNext()) {
| if ($rightInputRow == null) {
| $rightInputRow = (InternalRow) $rightInput.next();
| }
| $outputRightNoMatch
| if (shouldStop()) return;
|}
""".stripMargin
}
override protected def withNewChildrenInternal(
newLeft: SparkPlan, newRight: SparkPlan): SortMergeJoinExec =
copy(left = newLeft, right = newRight)
}
/**
* 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
* @param eagerCleanupResources the eager cleanup function to be invoked when no join row found
* @param onlyBufferFirstMatch [[bufferMatchingRows]] should buffer only the first matching row
*/
private[joins] class SortMergeJoinScanner(
streamedKeyGenerator: Projection,
bufferedKeyGenerator: Projection,
keyOrdering: Ordering[InternalRow],
streamedIter: RowIterator,
bufferedIter: RowIterator,
inMemoryThreshold: Int,
spillThreshold: Int,
spillSize: SQLMetric,
eagerCleanupResources: () => Unit,
onlyBufferFirstMatch: Boolean = false) {
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: ExternalAppendOnlyUnsafeRowArray =
new ExternalAppendOnlyUnsafeRowArray(inMemoryThreshold, spillThreshold)
// At the end of the task, update the task's spill size for buffered side.
TaskContext.get().addTaskCompletionListener[Unit](_ => {
spillSize += bufferedMatches.spillSize
})
// 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. If no
* join rows found, try to do the eager resources cleanup.
* @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.
}
val found = 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
}
}
if (!found) eagerCleanupResources()
found
}
/**
* Advances the streamed input iterator and buffers all rows from the buffered input that
* have matching keys. If no join rows found, try to do the eager resources cleanup.
* @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 = {
val found = 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
}
if (!found) eagerCleanupResources()
found
}
// --- 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 {
if (!onlyBufferFirstMatch || bufferedMatches.isEmpty) {
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.
val comp = keyOrdering.compare(leftRowKey, rightRowKey)
if (comp < 0) {
joinedRow(leftRow.copy(), rightNullRow)
advancedLeft()
} else if (comp > 0) {
joinedRow(leftNullRow, rightRow.copy())
advancedRight()
} else {
// Populate the buffers with rows matching the next key.
findMatchingRows(leftRowKey.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)
}
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