vvivekiyer commented on code in PR #9454: URL: https://github.com/apache/pinot/pull/9454#discussion_r980642014
########## pinot-segment-local/src/main/java/org/apache/pinot/segment/local/segment/index/loader/ForwardIndexHandler.java: ########## @@ -0,0 +1,269 @@ +/** + * 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.annotations.VisibleForTesting; +import com.google.common.base.Preconditions; +import java.io.File; +import java.math.BigDecimal; +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.Set; +import org.apache.commons.io.FileUtils; +import org.apache.pinot.segment.local.segment.readers.PinotSegmentColumnReader; +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.creator.SegmentVersion; +import org.apache.pinot.segment.spi.index.creator.ForwardIndexCreator; +import org.apache.pinot.segment.spi.index.reader.ForwardIndexReader; +import org.apache.pinot.segment.spi.store.ColumnIndexType; +import org.apache.pinot.segment.spi.store.SegmentDirectory; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Helper class used by {@link SegmentPreProcessor} to make changes to forward index and dictionary configs. Note + * that this handler only works if segment versions >= 3.0. The currently supported operations are: + * 1. Change compression on raw SV columns. + * + * TODO: Add support for the following: + * 1. Change compression for raw MV columns + * 2. Enable dictionary + * 3. Disable dictionary + */ +public class ForwardIndexHandler implements IndexHandler { + private static final Logger LOGGER = LoggerFactory.getLogger(ForwardIndexHandler.class); + + private final SegmentMetadata _segmentMetadata; + IndexLoadingConfig _indexLoadingConfig; + + protected enum Operation { + CHANGE_RAW_COMPRESSION_TYPE, + + // TODO: Add other operations like ENABLE_DICTIONARY, DISABLE_DICTIONARY. + } + + public ForwardIndexHandler(SegmentMetadata segmentMetadata, IndexLoadingConfig indexLoadingConfig) { + _segmentMetadata = segmentMetadata; + _indexLoadingConfig = indexLoadingConfig; + } + + @Override + public boolean needUpdateIndices(SegmentDirectory.Reader segmentReader) { + Map<String, Operation> columnOperationMap = computeOperation(segmentReader); + return !columnOperationMap.isEmpty(); + } + + @Override + public void updateIndices(SegmentDirectory.Writer segmentWriter, IndexCreatorProvider indexCreatorProvider) + throws Exception { + Map<String, Operation> columnOperationMap = computeOperation(segmentWriter); + if (columnOperationMap.isEmpty()) { + return; + } + + for (Map.Entry<String, Operation> entry : columnOperationMap.entrySet()) { + String column = entry.getKey(); + Operation operation = entry.getValue(); + + switch (operation) { + case CHANGE_RAW_COMPRESSION_TYPE: + rewriteRawForwardIndex(column, segmentWriter, indexCreatorProvider); + break; + // TODO: Add other operations here. + default: + break; + } + } + } + + @VisibleForTesting + Map<String, Operation> computeOperation(SegmentDirectory.Reader segmentReader) { + Map<String, Operation> columnOperationMap = new HashMap<>(); + + // Works only if the existing segment is V3. + if (_segmentMetadata.getVersion() != SegmentVersion.v3) { + return columnOperationMap; + } + + // From existing column config. + Set<String> existingAllColumns = _segmentMetadata.getAllColumns(); + Set<String> existingDictColumns = + segmentReader.toSegmentDirectory().getColumnsWithIndex(ColumnIndexType.DICTIONARY); + Set<String> existingNoDictColumns = new HashSet<>(); + for (String column : existingAllColumns) { + if (!existingDictColumns.contains(column)) { + existingNoDictColumns.add(column); + } + } + + // From new column config. + Set<String> newNoDictColumns = _indexLoadingConfig.getNoDictionaryColumns(); + + for (String column : existingAllColumns) { + if (existingNoDictColumns.contains(column) && newNoDictColumns.contains(column)) { + // Both existing and new column is RAW forward index encoded. Check if compression needs to be changed. + if (shouldChangeCompressionType(column, segmentReader)) { + columnOperationMap.put(column, Operation.CHANGE_RAW_COMPRESSION_TYPE); + } + } else if (existingNoDictColumns.contains(column) && !newNoDictColumns.contains(column)) { + // TODO: Enable dictionary + } else if (!existingNoDictColumns.contains(column) && newNoDictColumns.contains(column)) { + // TODO: Disable dictionary. + } else { Review Comment: Removed all unused conditions to avoid confusion. I'll add them when I make the actual change to enable/disable dictionary ########## pinot-segment-local/src/main/java/org/apache/pinot/segment/local/segment/index/loader/ForwardIndexHandler.java: ########## @@ -0,0 +1,269 @@ +/** + * 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.annotations.VisibleForTesting; +import com.google.common.base.Preconditions; +import java.io.File; +import java.math.BigDecimal; +import java.util.HashMap; +import java.util.HashSet; +import java.util.Map; +import java.util.Set; +import org.apache.commons.io.FileUtils; +import org.apache.pinot.segment.local.segment.readers.PinotSegmentColumnReader; +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.creator.SegmentVersion; +import org.apache.pinot.segment.spi.index.creator.ForwardIndexCreator; +import org.apache.pinot.segment.spi.index.reader.ForwardIndexReader; +import org.apache.pinot.segment.spi.store.ColumnIndexType; +import org.apache.pinot.segment.spi.store.SegmentDirectory; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + + +/** + * Helper class used by {@link SegmentPreProcessor} to make changes to forward index and dictionary configs. Note + * that this handler only works if segment versions >= 3.0. The currently supported operations are: Review Comment: A few reasons for not adding this support for versions < 3.0: 1. Most (if not all) of the usecases are in versions >= 3.0 2. Adding support will make the code less clean as the rewrite index logic will be different for v1 vs v3. 3. Adding support will lead to tech debt Given these reasons, it was decided to add this new feature support only for v3 segments. I've also added a comment clarifying this. I'm open to discuss this however and get feedback. Please let me know your thoughts. -- 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. 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