siddharthteotia commented on a change in pull request #4535: Implement DISTINCT clause URL: https://github.com/apache/incubator-pinot/pull/4535#discussion_r320621489
########## File path: pinot-core/src/main/java/org/apache/pinot/core/query/aggregation/function/DistinctAggregationFunction.java ########## @@ -0,0 +1,165 @@ +/** + * 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 com.google.common.base.Preconditions; +import java.util.Arrays; +import java.util.Iterator; +import javax.annotation.Nonnull; +import org.apache.pinot.common.data.FieldSpec; +import org.apache.pinot.common.function.AggregationFunctionType; +import org.apache.pinot.common.utils.DataSchema; +import org.apache.pinot.core.common.BlockValSet; +import org.apache.pinot.core.data.table.Key; +import org.apache.pinot.core.operator.transform.TransformBlockDataFetcher; +import org.apache.pinot.core.operator.transform.TransformResultMetadata; +import org.apache.pinot.core.query.aggregation.AggregationResultHolder; +import org.apache.pinot.core.query.aggregation.DistinctTable; +import org.apache.pinot.core.query.aggregation.ObjectAggregationResultHolder; +import org.apache.pinot.core.query.aggregation.groupby.GroupByResultHolder; +import org.apache.pinot.core.segment.index.readers.Dictionary; +import org.apache.pinot.pql.parsers.pql2.ast.FunctionCallAstNode; + + +/** + * DISTINCT clause in SQL is implemented as function in the + * execution engine of Pinot. + */ +public class DistinctAggregationFunction implements AggregationFunction<DistinctTable, Comparable> { + + private final DistinctTable _distinctTable; + private final String[] columnNames; + private FieldSpec.DataType[] _dataTypes; + private boolean init = false; + + DistinctAggregationFunction(String multiColumnExpression, int limit) { + _distinctTable = new DistinctTable(limit); + columnNames = multiColumnExpression.split(FunctionCallAstNode.DISTINCT_MULTI_COLUMN_SEPARATOR); + _dataTypes = new FieldSpec.DataType[columnNames.length]; + } + + @Nonnull + @Override + public AggregationFunctionType getType() { + return AggregationFunctionType.DISTINCT; + } + + @Nonnull + @Override + public String getColumnName(@Nonnull String column) { + return AggregationFunctionType.DISTINCT.getName() + "_" + column; + } + + @Nonnull + @Override + public DataSchema.ColumnDataType getIntermediateResultColumnType() { + return DataSchema.ColumnDataType.OBJECT; + } + + @Override + public void accept(@Nonnull AggregationFunctionVisitorBase visitor) { + visitor.visit(this); + } + + @Nonnull + @Override + public AggregationResultHolder createAggregationResultHolder() { + return new ObjectAggregationResultHolder(); + } + + @Override + public void aggregate(int records, AggregationResultHolder aggregationResultHolder, Review comment: Done ---------------------------------------------------------------- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. For queries about this service, please contact Infrastructure at: us...@infra.apache.org With regards, Apache Git Services --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
