siddharthteotia commented on code in PR #9810: URL: https://github.com/apache/pinot/pull/9810#discussion_r1035601212
########## pinot-segment-local/src/main/java/org/apache/pinot/segment/local/segment/index/loader/InvertedIndexAndDictionaryBasedForwardIndexCreator.java: ########## @@ -0,0 +1,619 @@ +/** + * 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.segment.index.loader; + +import com.google.common.base.Preconditions; +import java.io.File; +import java.io.IOException; +import java.util.HashMap; +import java.util.Map; +import org.apache.commons.io.FileUtils; +import org.apache.pinot.segment.local.segment.index.readers.BitmapInvertedIndexReader; +import org.apache.pinot.segment.spi.ColumnMetadata; +import org.apache.pinot.segment.spi.SegmentMetadata; +import org.apache.pinot.segment.spi.V1Constants; +import org.apache.pinot.segment.spi.compression.ChunkCompressionType; +import org.apache.pinot.segment.spi.creator.IndexCreationContext; +import org.apache.pinot.segment.spi.creator.IndexCreatorProvider; +import org.apache.pinot.segment.spi.index.creator.ForwardIndexCreator; +import org.apache.pinot.segment.spi.index.reader.Dictionary; +import org.apache.pinot.segment.spi.memory.PinotDataBuffer; +import org.apache.pinot.segment.spi.store.ColumnIndexType; +import org.apache.pinot.segment.spi.store.SegmentDirectory; +import org.apache.pinot.spi.data.FieldSpec; +import org.apache.pinot.spi.utils.BigDecimalUtils; +import org.apache.pinot.spi.utils.ByteArray; +import org.roaringbitmap.buffer.ImmutableRoaringBitmap; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import static org.apache.pinot.segment.spi.V1Constants.MetadataKeys.Column.DICTIONARY_ELEMENT_SIZE; +import static org.apache.pinot.segment.spi.V1Constants.MetadataKeys.Column.HAS_DICTIONARY; +import static org.apache.pinot.segment.spi.V1Constants.MetadataKeys.Column.MAX_MULTI_VALUE_ELEMENTS; +import static org.apache.pinot.segment.spi.V1Constants.MetadataKeys.Column.TOTAL_NUMBER_OF_ENTRIES; +import static org.apache.pinot.segment.spi.V1Constants.MetadataKeys.Column.getKeyFor; + + +/** + * Helper classed used by the {@link SegmentPreProcessor} to generate the forward index from inverted index and + * dictionary when the forward index is enabled for columns where it was previously disabled. This is also invoked by + * the {@link IndexHandler} code in scenarios where the forward index needs to be temporarily created to generate other + * indexes for the given column. In such cases the forward index will be cleaned up after the {@link IndexHandler} code + * completes. + * + * For multi-value columns the following invariants cannot be maintained: + * - Ordering of elements within a given multi-value row. This will always be a limitation. + * - Data loss is possible if there repeats for elements within a given multi-value row. This limitation will be Review Comment: (nit) suggest removing this from here since it is already called out as a TODO in the next line -- 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: commits-unsubscr...@pinot.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: commits-unsubscr...@pinot.apache.org For additional commands, e-mail: commits-h...@pinot.apache.org
