tarun11Mavani commented on code in PR #16344: URL: https://github.com/apache/pinot/pull/16344#discussion_r2285154325
########## pinot-segment-local/src/main/java/org/apache/pinot/segment/local/realtime/converter/stats/CompactedDictEncodedColumnStatistics.java: ########## @@ -0,0 +1,171 @@ +/** + * 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.segment.local.realtime.converter.stats; + +import java.lang.reflect.Array; +import java.util.ArrayList; +import java.util.Comparator; +import java.util.HashSet; +import java.util.List; +import java.util.Set; +import org.apache.pinot.segment.spi.datasource.DataSource; +import org.apache.pinot.segment.spi.index.mutable.MutableForwardIndex; +import org.apache.pinot.segment.spi.index.mutable.ThreadSafeMutableRoaringBitmap; +import org.apache.pinot.segment.spi.index.reader.Dictionary; + + +/** + * Column statistics for dictionary columns with dictionary-encoded forward indexes. + * Uses direct getDictId() calls for single-value columns and getDictIdMV() calls for multi-value columns + * to find which dictionary entries are used by valid documents. + * + * This is used when: + * - Column has a dictionary (dataSource.getDictionary() != null) + * - Forward index is dictionary-encoded (forwardIndex.isDictionaryEncoded() == true) + * - Commit-time compaction is enabled + */ +public class CompactedDictEncodedColumnStatistics extends MutableColumnStatistics { + private final Set<Integer> _usedDictIds; + private final int _compactedCardinality; + private final DataSource _dataSource; + private final Object _compactedUniqueValues; + private int _maxNumberOfMultiValues = 1; // Track max multi-values for buffer allocation + private int _totalNumberOfEntries = 0; // Total number of entries in the column + private Object _minValue; // Track min value from valid documents + private Object _maxValue; // Track max value from valid documents + + public CompactedDictEncodedColumnStatistics(DataSource dataSource, int[] sortedDocIds, + ThreadSafeMutableRoaringBitmap validDocIds) { + super(dataSource, sortedDocIds); + _dataSource = dataSource; + + String columnName = dataSource.getDataSourceMetadata().getFieldSpec().getName(); + + // Find which dictionary IDs are actually used by valid documents + _usedDictIds = new HashSet<>(); + MutableForwardIndex forwardIndex = (MutableForwardIndex) dataSource.getForwardIndex(); + Dictionary dictionary = dataSource.getDictionary(); + + // Iterate through valid document IDs + int[] validDocIdsArray = validDocIds.getMutableRoaringBitmap().toArray(); + boolean isSingleValue = forwardIndex.isSingleValue(); + + for (int docId : validDocIdsArray) { + if (isSingleValue) { + // Single-value column: use getDictId() + int dictId = forwardIndex.getDictId(docId); + _usedDictIds.add(dictId); + _totalNumberOfEntries++; // Count each valid document + + // Track min/max values + Object value = dictionary.get(dictId); + updateMinMaxValue(value); + } else { + // Multi-value column: use getDictIdMV() + int[] dictIds = forwardIndex.getDictIdMV(docId); + _totalNumberOfEntries += dictIds.length; // Count all values in this document + _maxNumberOfMultiValues = Math.max(_maxNumberOfMultiValues, dictIds.length); + for (int dictId : dictIds) { + _usedDictIds.add(dictId); + + // Track min/max values + Object value = dictionary.get(dictId); + updateMinMaxValue(value); + } + } + } + + _compactedCardinality = _usedDictIds.size(); + + // Create compacted unique values array with only used dictionary values + Object originalValues = dictionary.getSortedValues(); Review Comment: We cannot simply iterate getSortedValues() and filter by _usedDictIds because that would require calling dictionary.indexOf() for each value, resulting in O(n²) complexity for mutable dictionaries. Instead, we collect the used values directly using the known dictionary IDs and sort them. -- 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. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
