Github user rxin commented on a diff in the pull request:
https://github.com/apache/spark/pull/7813#discussion_r36057881
--- Diff:
sql/core/src/main/scala/org/apache/spark/sql/execution/aggregate/AggregationIterator.scala
---
@@ -0,0 +1,490 @@
+/*
+ * 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.aggregate
+
+import org.apache.spark.Logging
+import org.apache.spark.sql.catalyst.InternalRow
+import org.apache.spark.sql.catalyst.expressions._
+import org.apache.spark.sql.catalyst.expressions.aggregate._
+import org.apache.spark.unsafe.KVIterator
+
+import scala.collection.mutable.ArrayBuffer
+
+/**
+ * The base class of [[SortBasedAggregationIterator]] and
[[UnsafeHybridAggregationIterator]].
+ * It mainly contains two parts:
+ * 1. It initializes aggregate functions.
+ * 2. It creates two functions, `processRow` and `generateOutput` based on
[[AggregateMode]] of
+ * its aggregate functions. `processRow` is the function to handle an
input. `generateOutput`
+ * is used to generate result.
+ */
+abstract class AggregationIterator(
+ groupingKeyAttributes: Seq[Attribute],
+ valueAttributes: Seq[Attribute],
+ nonCompleteAggregateExpressions: Seq[AggregateExpression2],
+ nonCompleteAggregateAttributes: Seq[Attribute],
+ completeAggregateExpressions: Seq[AggregateExpression2],
+ completeAggregateAttributes: Seq[Attribute],
+ initialInputBufferOffset: Int,
+ resultExpressions: Seq[NamedExpression],
+ newMutableProjection: (Seq[Expression], Seq[Attribute]) => (() =>
MutableProjection),
+ outputsUnsafeRows: Boolean)
+ extends Iterator[InternalRow] with Logging {
+
+
///////////////////////////////////////////////////////////////////////////
+ // Initializing functions.
+
///////////////////////////////////////////////////////////////////////////
+
+ // An Seq of all AggregateExpressions.
+ // It is important that all AggregateExpressions with the mode Partial,
PartialMerge or Final
+ // are at the beginning of the allAggregateExpressions.
+ protected val allAggregateExpressions =
+ nonCompleteAggregateExpressions ++ completeAggregateExpressions
+
+ require(
+ allAggregateExpressions.map(_.mode).distinct.length <= 2,
+ s"$allAggregateExpressions are not supported becuase they have more
than 2 distinct modes.")
+
+ /**
+ * The distinct modes of AggregateExpressions. Right now, we can handle
the following mode:
+ * - Partial-only: all AggregateExpressions have the mode of Partial;
+ * - PartialMerge-only: all AggregateExpressions have the mode of
PartialMerge);
+ * - Final-only: all AggregateExpressions have the mode of Final;
+ * - Final-Complete: some AggregateExpressions have the mode of Final
and
+ * others have the mode of Complete;
+ * - Complete-only: nonCompleteAggregateExpressions is empty and we
have AggregateExpressions
+ * with mode Complete in completeAggregateExpressions; and
+ * - Grouping-only: there is no AggregateExpression.
+ */
+ protected val aggregationMode: (Option[AggregateMode],
Option[AggregateMode]) =
+ nonCompleteAggregateExpressions.map(_.mode).distinct.headOption ->
+ completeAggregateExpressions.map(_.mode).distinct.headOption
+
+ // Initialize all AggregateFunctions by binding references if necessary,
+ // and set inputBufferOffset and mutableBufferOffset.
+ protected val allAggregateFunctions: Array[AggregateFunction2] = {
+ var mutableBufferOffset = 0
+ var inputBufferOffset: Int = initialInputBufferOffset
+ val functions = new
Array[AggregateFunction2](allAggregateExpressions.length)
+ var i = 0
+ while (i < allAggregateExpressions.length) {
+ val func = allAggregateExpressions(i).aggregateFunction
+ val funcWithBoundReferences = allAggregateExpressions(i).mode match {
+ case Partial | Complete if !func.isInstanceOf[AlgebraicAggregate]
=>
+ // We need to create BoundReferences if the function is not an
+ // AlgebraicAggregate (it does not support code-gen) and the
mode of
+ // this function is Partial or Complete because we will call
eval of this
+ // function's children in the update method of this aggregate
function.
+ // Those eval calls require BoundReferences to work.
+ BindReferences.bindReference(func, valueAttributes)
+ case _ =>
+ // We only need to set inputBufferOffset for aggregate functions
with mode
+ // PartialMerge and Final.
+ func.withNewInputBufferOffset(inputBufferOffset)
+ inputBufferOffset += func.bufferSchema.length
+ func
+ }
+ // Set mutableBufferOffset for this function. It is important that
setting
+ // mutableBufferOffset happens after all potential bindReference
operations
+ // because bindReference will create a new instance of the function.
+
funcWithBoundReferences.withNewMutableBufferOffset(mutableBufferOffset)
+ mutableBufferOffset += funcWithBoundReferences.bufferSchema.length
+ functions(i) = funcWithBoundReferences
+ i += 1
+ }
+ functions
+ }
+
+ // Positions of those non-algebraic aggregate functions in
allAggregateFunctions.
+ // For example, we have func1, func2, func3, func4 in
aggregateFunctions, and
+ // func2 and func3 are non-algebraic aggregate functions.
+ // nonAlgebraicAggregateFunctionPositions will be [1, 2].
+ private[this] val allNonAlgebraicAggregateFunctionPositions: Array[Int]
= {
+ val positions = new ArrayBuffer[Int]()
+ var i = 0
+ while (i < allAggregateFunctions.length) {
+ allAggregateFunctions(i) match {
+ case agg: AlgebraicAggregate =>
+ case _ => positions += i
+ }
+ i += 1
+ }
+ positions.toArray
+ }
+
+ // All AggregateFunctions functions with mode Partial, PartialMerge, or
Final.
+ private[this] val nonCompleteAggregateFunctions:
Array[AggregateFunction2] =
+ allAggregateFunctions.take(nonCompleteAggregateExpressions.length)
+
+ // All non-algebraic aggregate functions with mode Partial,
PartialMerge, or Final.
+ private[this] val nonCompleteNonAlgebraicAggregateFunctions:
Array[AggregateFunction2] =
+ nonCompleteAggregateFunctions.collect {
+ case func: AggregateFunction2 if
!func.isInstanceOf[AlgebraicAggregate] => func
+ }
+
+ // The projection used to initialize buffer values for all
AlgebraicAggregates.
+ private[this] val algebraicInitialProjection = {
+ val initExpressions = allAggregateFunctions.flatMap {
+ case ae: AlgebraicAggregate => ae.initialValues
+ case agg: AggregateFunction2 =>
Seq.fill(agg.bufferAttributes.length)(NoOp)
+ }
+ newMutableProjection(initExpressions, Nil)()
+ }
+
+ // All non-Algebraic AggregateFunctions.
+ private[this] val allNonAlgebraicAggregateFunctions =
+ allNonAlgebraicAggregateFunctionPositions.map(allAggregateFunctions)
+
+
///////////////////////////////////////////////////////////////////////////
+ // Methods and fields used by sub-classes.
+
///////////////////////////////////////////////////////////////////////////
+
+ // Initializing functions used to process a row.
+ protected val processRow: (MutableRow, InternalRow) => Unit = {
+ val rowToBeProcessed = new JoinedRow
+ val aggregationBufferSchema =
allAggregateFunctions.flatMap(_.bufferAttributes)
+ aggregationMode match {
+ // Partial-only
+ case (Some(Partial), None) =>
+ val updateExpressions = nonCompleteAggregateFunctions.flatMap {
+ case ae: AlgebraicAggregate => ae.updateExpressions
+ case agg: AggregateFunction2 =>
Seq.fill(agg.bufferAttributes.length)(NoOp)
+ }
+ val algebraicUpdateProjection =
+ newMutableProjection(updateExpressions, aggregationBufferSchema
++ valueAttributes)()
+
+ (currentBuffer: MutableRow, row: InternalRow) => {
+ algebraicUpdateProjection.target(currentBuffer)
+ // Process all algebraic aggregate functions.
+ algebraicUpdateProjection(rowToBeProcessed(currentBuffer, row))
+ // Process all non-algebraic aggregate functions.
+ var i = 0
+ while (i < nonCompleteNonAlgebraicAggregateFunctions.length) {
+
nonCompleteNonAlgebraicAggregateFunctions(i).update(currentBuffer, row)
+ i += 1
+ }
+ }
+
+ // PartialMerge-only or Final-only
+ case (Some(PartialMerge), None) | (Some(Final), None) =>
+ val inputAggregationBufferSchema = if (initialInputBufferOffset ==
0) {
+ // If initialInputBufferOffset, the input value does not contain
+ // grouping keys.
+ // This part is pretty hacky.
+ allAggregateFunctions.flatMap(_.cloneBufferAttributes).toSeq
+ } else {
+ groupingKeyAttributes ++
allAggregateFunctions.flatMap(_.cloneBufferAttributes)
+ }
+ // val inputAggregationBufferSchema =
+ // groupingKeyAttributes ++
+ // allAggregateFunctions.flatMap(_.cloneBufferAttributes)
+ val mergeExpressions = nonCompleteAggregateFunctions.flatMap {
+ case ae: AlgebraicAggregate => ae.mergeExpressions
+ case agg: AggregateFunction2 =>
Seq.fill(agg.bufferAttributes.length)(NoOp)
+ }
+ // This projection is used to merge buffer values for all
AlgebraicAggregates.
+ val algebraicMergeProjection =
+ newMutableProjection(
+ mergeExpressions,
+ aggregationBufferSchema ++ inputAggregationBufferSchema)()
+
+ (currentBuffer: MutableRow, row: InternalRow) => {
+ // Process all algebraic aggregate functions.
+
algebraicMergeProjection.target(currentBuffer)(rowToBeProcessed(currentBuffer,
row))
+ // Process all non-algebraic aggregate functions.
+ var i = 0
+ while (i < nonCompleteNonAlgebraicAggregateFunctions.length) {
+
nonCompleteNonAlgebraicAggregateFunctions(i).merge(currentBuffer, row)
+ i += 1
+ }
+ }
+
+ // Final-Complete
+ case (Some(Final), Some(Complete)) =>
+ val completeAggregateFunctions: Array[AggregateFunction2] =
+
allAggregateFunctions.takeRight(completeAggregateExpressions.length)
+ // All non-algebraic aggregate functions with mode Complete.
+ val completeNonAlgebraicAggregateFunctions:
Array[AggregateFunction2] =
+ completeAggregateFunctions.collect {
+ case func: AggregateFunction2 if
!func.isInstanceOf[AlgebraicAggregate] => func
+ }
+
+ // The first initialInputBufferOffset values of the input
aggregation buffer is
+ // for grouping expressions and distinct columns.
+ val groupingAttributesAndDistinctColumns =
valueAttributes.take(initialInputBufferOffset)
+
+ val completeOffsetExpressions =
+
Seq.fill(completeAggregateFunctions.map(_.bufferAttributes.length).sum)(NoOp)
+ // We do not touch buffer values of aggregate functions with the
Final mode.
+ val finalOffsetExpressions =
+
Seq.fill(nonCompleteAggregateFunctions.map(_.bufferAttributes.length).sum)(NoOp)
+
+ val mergeInputSchema =
+ aggregationBufferSchema ++
+ groupingAttributesAndDistinctColumns ++
+ nonCompleteAggregateFunctions.flatMap(_.cloneBufferAttributes)
+ val mergeExpressions =
+ nonCompleteAggregateFunctions.flatMap {
+ case ae: AlgebraicAggregate => ae.mergeExpressions
+ case agg: AggregateFunction2 =>
Seq.fill(agg.bufferAttributes.length)(NoOp)
+ } ++ completeOffsetExpressions
+ val finalAlgebraicMergeProjection =
+ newMutableProjection(mergeExpressions, mergeInputSchema)()
+
+ val updateExpressions =
+ finalOffsetExpressions ++ completeAggregateFunctions.flatMap {
+ case ae: AlgebraicAggregate => ae.updateExpressions
+ case agg: AggregateFunction2 =>
Seq.fill(agg.bufferAttributes.length)(NoOp)
+ }
+ val completeAlgebraicUpdateProjection =
+ newMutableProjection(updateExpressions, aggregationBufferSchema
++ valueAttributes)()
+
+ (currentBuffer: MutableRow, row: InternalRow) => {
+ val input = rowToBeProcessed(currentBuffer, row)
+ // For all aggregate functions with mode Complete, update
buffers.
+ completeAlgebraicUpdateProjection.target(currentBuffer)(input)
+ var i = 0
+ while (i < completeNonAlgebraicAggregateFunctions.length) {
+
completeNonAlgebraicAggregateFunctions(i).update(currentBuffer, row)
+ i += 1
+ }
+
+ // For all aggregate functions with mode Final, merge buffers.
+ finalAlgebraicMergeProjection.target(currentBuffer)(input)
+ i = 0
+ while (i < nonCompleteNonAlgebraicAggregateFunctions.length) {
+
nonCompleteNonAlgebraicAggregateFunctions(i).merge(currentBuffer, row)
+ i += 1
+ }
+ }
+
+ // Complete-only
+ case (None, Some(Complete)) =>
+ val completeAggregateFunctions: Array[AggregateFunction2] =
+
allAggregateFunctions.takeRight(completeAggregateExpressions.length)
+ // All non-algebraic aggregate functions with mode Complete.
+ val completeNonAlgebraicAggregateFunctions:
Array[AggregateFunction2] =
+ completeAggregateFunctions.collect {
+ case func: AggregateFunction2 if
!func.isInstanceOf[AlgebraicAggregate] => func
+ }
+
+ val updateExpressions =
+ completeAggregateFunctions.flatMap {
+ case ae: AlgebraicAggregate => ae.updateExpressions
+ case agg: AggregateFunction2 =>
Seq.fill(agg.bufferAttributes.length)(NoOp)
+ }
+ val completeAlgebraicUpdateProjection =
+ newMutableProjection(updateExpressions, aggregationBufferSchema
++ valueAttributes)()
+
+ (currentBuffer: MutableRow, row: InternalRow) => {
+ val input = rowToBeProcessed(currentBuffer, row)
+ // For all aggregate functions with mode Complete, update
buffers.
+ completeAlgebraicUpdateProjection.target(currentBuffer)(input)
+ var i = 0
+ while (i < completeNonAlgebraicAggregateFunctions.length) {
+
completeNonAlgebraicAggregateFunctions(i).update(currentBuffer, row)
+ i += 1
+ }
+ }
+
+ // Grouping only.
+ case (None, None) => (currentBuffer: MutableRow, row: InternalRow)
=> {}
+
+ case other =>
+ sys.error(
--- End diff --
this is an error case -- we should throw IllegalStateException, and make it
clear that if we hit this path, it's a bug.
Right now it sounds as if this operator just cannot handle a legitimate
case.
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