vvivekiyer commented on code in PR #10845: URL: https://github.com/apache/pinot/pull/10845#discussion_r1248152940
########## pinot-query-runtime/src/main/java/org/apache/pinot/query/runtime/operator/MultistageAggregationExecutor.java: ########## @@ -0,0 +1,192 @@ +/** + * 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.pinot.query.runtime.operator; + +import com.google.common.base.Preconditions; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.Map; +import org.apache.pinot.common.datablock.DataBlock; +import org.apache.pinot.common.request.context.ExpressionContext; +import org.apache.pinot.common.utils.DataSchema; +import org.apache.pinot.core.common.BlockValSet; +import org.apache.pinot.core.common.IntermediateStageBlockValSet; +import org.apache.pinot.core.query.aggregation.AggregationResultHolder; +import org.apache.pinot.core.query.aggregation.function.AggregationFunction; +import org.apache.pinot.query.runtime.blocks.TransferableBlock; + +/** + * Class that executes all aggregation functions (without group-bys) for the multistage AggregateOperator. + */ +public class MultistageAggregationExecutor { + private final NewAggregateOperator.Mode _mode; + // The identifier operands for the aggregation function only store the column name. This map contains mapping + // from column name to their index. + private final Map<String, Integer> _colNameToIndexMap; + + private final AggregationFunction[] _aggFunctions; + + // Result holders for each mode. + private final AggregationResultHolder[] _aggregateResultHolder; + private final Object[] _mergeResultHolder; + private final Object[] _finalResultHolder; + + public MultistageAggregationExecutor(AggregationFunction[] aggFunctions, NewAggregateOperator.Mode mode, + Map<String, Integer> colNameToIndexMap) { + _aggFunctions = aggFunctions; + _mode = mode; + _colNameToIndexMap = colNameToIndexMap; + + _aggregateResultHolder = new AggregationResultHolder[aggFunctions.length]; + _mergeResultHolder = new Object[aggFunctions.length]; + _finalResultHolder = new Object[aggFunctions.length]; + + for (int i = 0; i < _aggFunctions.length; i++) { + _aggregateResultHolder[i] = _aggFunctions[i].createAggregationResultHolder(); + } + } + + /** + * Performs aggregation for the data in the block. + */ + public void processBlock(TransferableBlock block, DataSchema inputDataSchema) { + if (_mode.equals(NewAggregateOperator.Mode.AGGREGATE)) { + processAggregate(block, inputDataSchema); + } else if (_mode.equals(NewAggregateOperator.Mode.MERGE)) { + processMerge(block); + } else if (_mode.equals(NewAggregateOperator.Mode.EXTRACT_RESULT)) { + collectResult(block); + } + } + + /** + * Fetches the result. + */ + public List<Object[]> getResult() { + List<Object[]> rows = new ArrayList<>(); + Object[] row = new Object[_aggFunctions.length]; + + for (int i = 0; i < _aggFunctions.length; i++) { + AggregationFunction aggFunction = _aggFunctions[i]; + if (_mode.equals(NewAggregateOperator.Mode.MERGE)) { + row[i] = _mergeResultHolder[i]; + } else if (_mode.equals(NewAggregateOperator.Mode.AGGREGATE)) { + row[i] = aggFunction.extractAggregationResult(_aggregateResultHolder[i]); + } else { + assert _mode.equals(NewAggregateOperator.Mode.EXTRACT_RESULT); + Comparable result = aggFunction.extractFinalResult(_finalResultHolder[i]); + row[i] = result == null ? null : aggFunction.getFinalResultColumnType().convert(result); + } + } + rows.add(row); + return rows; + } + + /** + * @return an empty agg result block for non-group-by aggregation. + */ + public Object[] constructEmptyAggResultRow() { + Object[] row = new Object[_aggFunctions.length]; + for (int i = 0; i < _aggFunctions.length; i++) { + AggregationFunction aggFunction = _aggFunctions[i]; + row[i] = aggFunction.extractAggregationResult(aggFunction.createAggregationResultHolder()); + } + return row; + } + + private void processAggregate(TransferableBlock block, DataSchema inputDataSchema) { + for (int i = 0; i < _aggFunctions.length; i++) { + AggregationFunction aggregationFunction = _aggFunctions[i]; + Map<ExpressionContext, BlockValSet> blockValSetMap = + getBlockValSetMap(aggregationFunction, block, inputDataSchema); + aggregationFunction.aggregate(block.getNumRows(), _aggregateResultHolder[i], blockValSetMap); + } + } + + private void processMerge(TransferableBlock block) { + List<Object[]> container = block.getContainer(); + + for (int i = 0; i < _aggFunctions.length; i++) { + List<ExpressionContext> expressions = _aggFunctions[i].getInputExpressions(); + for (Object[] row : container) { + Object intermediateResultToMerge = extractValueFromRow(row, expressions); + Object mergedIntermediateResult = _mergeResultHolder[i]; + + // Not all V1 aggregation functions have null-handling logic. Handle null values before calling merge. + if (intermediateResultToMerge == null) { + continue; + } + if (mergedIntermediateResult == null) { + _mergeResultHolder[i] = intermediateResultToMerge; + continue; + } + + _mergeResultHolder[i] = _aggFunctions[i].merge(intermediateResultToMerge, mergedIntermediateResult); + } + } + } + + private void collectResult(TransferableBlock block) { + List<Object[]> container = block.getContainer(); + assert container.size() == 1; + Object[] row = container.get(0); + for (int i = 0; i < _aggFunctions.length; i++) { + List<ExpressionContext> expressions = _aggFunctions[i].getInputExpressions(); + _finalResultHolder[i] = extractValueFromRow(row, expressions); + } + } + + private Map<ExpressionContext, BlockValSet> getBlockValSetMap(AggregationFunction aggFunction, + TransferableBlock block, DataSchema inputDataSchema) { + List<ExpressionContext> expressions = aggFunction.getInputExpressions(); + int numExpressions = expressions.size(); + if (numExpressions == 0) { + return Collections.emptyMap(); + } + + Preconditions.checkState(numExpressions == 1, "Cannot handle more than one identifier in aggregation function."); + ExpressionContext expression = expressions.get(0); + Preconditions.checkState(expression.getType().equals(ExpressionContext.Type.IDENTIFIER)); + int index = _colNameToIndexMap.get(expression.getIdentifier()); + + DataSchema.ColumnDataType dataType = inputDataSchema.getColumnDataType(index); + Preconditions.checkState(block.getType().equals(DataBlock.Type.ROW), "Datablock type is not ROW"); + return Collections.singletonMap(expression, + new IntermediateStageBlockValSet(dataType, block.getDataBlock(), index)); Review Comment: Added a TODO as discussed offline. -- This is an automated message from the Apache Git Service. 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