siddharthteotia commented on code in PR #10636: URL: https://github.com/apache/pinot/pull/10636#discussion_r1188230046
########## pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/ChildAggregationFunction.java: ########## @@ -0,0 +1,160 @@ +/** + * 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.core.query.aggregation.function; + +import java.util.ArrayList; +import java.util.List; +import java.util.Map; +import java.util.stream.Collectors; +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.query.aggregation.AggregationResultHolder; +import org.apache.pinot.core.query.aggregation.groupby.DummyAggregationResultHolder; +import org.apache.pinot.core.query.aggregation.groupby.DummyGroupByResultHolder; +import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder; +import org.apache.pinot.spi.utils.CommonConstants; + + +/** + * Child aggregation function is used for a result placeholder during the query processing, + * It holds the position of the original aggregation function in the query + * and use its name to denote which parent aggregation function it belongs to. + * The name also serves as the key to retrieve the result from the parent aggregation function + * result holder. + * Please look at getResultColumnName() for the detailed format of the name. + * Please look at ArgMinMaxRewriter as an example of how a child aggregation function is created. + */ +public abstract class ChildAggregationFunction implements AggregationFunction<Long, Long> { + + private static final int CHILD_AGGREGATION_FUNCTION_ID_OFFSET = 0; + private static final int CHILD_AGGREGATION_FUNCTION_COLUMN_KEY_OFFSET = 1; + private final ExpressionContext _childFunctionKeyInParent; + private final List<ExpressionContext> _resultNameOperands; + private final ExpressionContext _childFunctionID; + + ChildAggregationFunction(List<ExpressionContext> operands) { + _childFunctionID = operands.get(CHILD_AGGREGATION_FUNCTION_ID_OFFSET); + _childFunctionKeyInParent = operands.get(CHILD_AGGREGATION_FUNCTION_COLUMN_KEY_OFFSET); + _resultNameOperands = operands.subList(CHILD_AGGREGATION_FUNCTION_COLUMN_KEY_OFFSET + 1, operands.size()); + } + + @Override + public List<ExpressionContext> getInputExpressions() { + ArrayList<ExpressionContext> expressionContexts = new ArrayList<>(); + expressionContexts.add(_childFunctionID); + expressionContexts.add(_childFunctionKeyInParent); + expressionContexts.addAll(_resultNameOperands); + return expressionContexts; + } + + @Override + public final AggregationResultHolder createAggregationResultHolder() { + return new DummyAggregationResultHolder(); + } + + @Override + public final GroupByResultHolder createGroupByResultHolder(int initialCapacity, int maxCapacity) { + return new DummyGroupByResultHolder(); + } + + @Override + public final void aggregate(int length, AggregationResultHolder aggregationResultHolder, + Map<ExpressionContext, BlockValSet> blockValSetMap) { + } + + @Override + public final void aggregateGroupBySV(int length, int[] groupKeyArray, GroupByResultHolder groupByResultHolder, + Map<ExpressionContext, BlockValSet> blockValSetMap) { + } + + @Override + public final void aggregateGroupByMV(int length, int[][] groupKeysArray, GroupByResultHolder groupByResultHolder, + Map<ExpressionContext, BlockValSet> blockValSetMap) { + } + + @Override + public final Long extractAggregationResult(AggregationResultHolder aggregationResultHolder) { + return 0L; + } + + @Override + public final Long extractGroupByResult(GroupByResultHolder groupByResultHolder, int groupKey) { + return 0L; + } + + @Override + public final Long merge(Long intermediateResult1, Long intermediateResult2) { + return 0L; + } + + @Override + public final DataSchema.ColumnDataType getIntermediateResultColumnType() { + return DataSchema.ColumnDataType.LONG; + } + + @Override + public final DataSchema.ColumnDataType getFinalResultColumnType() { + return DataSchema.ColumnDataType.UNKNOWN; + } + + @Override + public final Long extractFinalResult(Long longValue) { + return 0L; + } + + /** + * The name of the column as follows: + * CHILD_AGGREGATION_NAME_PREFIX + actual function type + operands + CHILD_AGGREGATION_SEPERATOR + * + actual function type + parent aggregation function id + CHILD_KEY_SEPERATOR + column key in parent function + * e.g. if the child aggregation function is "argmax(0,a,b,x)", the name of the column is + * "pinotchildaggregationargmax(a,b,x)@argmax0_x" + */ + @Override + public final String getResultColumnName() { + String type = getType().getName().toLowerCase(); + return CommonConstants.RewriterConstants.CHILD_AGGREGATION_NAME_PREFIX Review Comment: May be better to use StringBuilder in general but since this function will be called once per query, it should be fine for now -- This is an automated message from the Apache Git Service. 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