RussellSpitzer commented on a change in pull request #2585: URL: https://github.com/apache/iceberg/pull/2585#discussion_r631514299
########## File path: core/src/main/java/org/apache/iceberg/actions/BinPackStrategy.java ########## @@ -0,0 +1,197 @@ +/* + * 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.iceberg.actions; + +import java.util.List; +import java.util.Map; +import java.util.Set; +import java.util.stream.Collectors; +import java.util.stream.StreamSupport; +import org.apache.iceberg.FileScanTask; +import org.apache.iceberg.TableProperties; +import org.apache.iceberg.actions.RewriteDataFiles.Strategy; +import org.apache.iceberg.relocated.com.google.common.collect.FluentIterable; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableSet; +import org.apache.iceberg.util.BinPacking; +import org.apache.iceberg.util.BinPacking.ListPacker; +import org.apache.iceberg.util.PropertyUtil; + +/** + * A rewrite strategy for datafiles which determines which files to rewrite + * based on their size. If files are either smaller than the min-file-size-bytes threshold or + * larger than the max-file-size-bytes threshold, they are considered targets for being rewritten. + * <p> + * Once filtered files are grouped based on a {@link BinPacking} into groups defined + * by max group size. Groups will be considered for rewriting if they contain more files + * than min-input-files and would produce more files than min-output-files. + */ +abstract class BinPackStrategy implements RewriteStrategy { + + /** + * Minimum number of files that need to be in a file group to be considered + * for rewriting. This is considered in conjunction with min-num-output-files, both + * conditions must pass to consider a group of files to be rewritten. + */ + public static final String MIN_INPUT_FILES = "min-input-files"; + public static final int MIN_INPUT_FILES_DEFAULT = 1; + + /** + * Minimum number of files we want to be created by file group when being + * rewritten. This is considered in conjunction with min-num-input-files, both + * conditions must pass to consider a group of files to be rewritten. + */ + public static final String MIN_OUTPUT_FILES = "min-output-files"; + public static final int MIN_OUTPUT_FILES_DEFAULT = 1; + + /** + * Adjusts files which will be considered for rewriting. Files smaller than + * min-file-size-bytes will be considered for rewriting. This functions independently + * of max-file-size-bytes. + * <p> + * Defaults to 75% of the target file size + */ + public static final String MIN_FILE_SIZE_BYTES = "min-file-size-bytes"; + public static final double MIN_FILE_SIZE_DEFAULT_RATIO = 0.75d; + + /** + * Adjusts files which will be considered for rewriting. Files larger than + * max-file-size-bytes will be considered for rewriting. This functions independently + * of min-file-size-bytes. + * <p> + * Defaults to 180% of the target file size + */ + public static final String MAX_FILE_SIZE_BYTES = "max-file-size-bytes"; + public static final double MAX_FILE_SIZE_DEFAULT_RATIO = 1.80d; + + private int minInputFiles; + private int minOutputFiles; + private long minFileSize; + private long maxFileSize; + private long targetFileSize; + private long maxGroupSize; + + @Override + public String name() { + return Strategy.BINPACK.name(); + } + + @Override + public Set<String> validOptions() { + return ImmutableSet.of( + MIN_INPUT_FILES, + MIN_OUTPUT_FILES, + MIN_FILE_SIZE_BYTES, + MAX_FILE_SIZE_BYTES + ); + } + + @Override + public RewriteStrategy options(Map<String, String> options) { + targetFileSize = PropertyUtil.propertyAsLong(options, + RewriteDataFiles.TARGET_FILE_SIZE_BYTES, + PropertyUtil.propertyAsLong( + table().properties(), + TableProperties.WRITE_TARGET_FILE_SIZE_BYTES, + TableProperties.WRITE_TARGET_FILE_SIZE_BYTES_DEFAULT)); + + minFileSize = PropertyUtil.propertyAsLong(options, + MIN_FILE_SIZE_BYTES, + (long) (targetFileSize * MIN_FILE_SIZE_DEFAULT_RATIO)); + + maxFileSize = PropertyUtil.propertyAsLong(options, + MAX_FILE_SIZE_BYTES, + (long) (targetFileSize * MAX_FILE_SIZE_DEFAULT_RATIO)); + + maxGroupSize = PropertyUtil.propertyAsLong(options, + RewriteDataFiles.MAX_FILE_GROUP_SIZE_BYTES, + RewriteDataFiles.MAX_FILE_GROUP_SIZE_BYTES_DEFAULT); + + minOutputFiles = PropertyUtil.propertyAsInt(options, + MIN_OUTPUT_FILES, + MIN_OUTPUT_FILES_DEFAULT); + + minInputFiles = PropertyUtil.propertyAsInt(options, + MIN_INPUT_FILES, + MIN_INPUT_FILES_DEFAULT); + + validateOptions(); + return this; + } + + @Override + public Iterable<FileScanTask> selectFilesToRewrite(Iterable<FileScanTask> dataFiles) { + return FluentIterable.from(dataFiles) + .filter(scanTask -> scanTask.length() < minFileSize || scanTask.length() > maxFileSize); + } + + @Override + public Iterable<List<FileScanTask>> planFileGroups(Iterable<FileScanTask> dataFiles) { + ListPacker<FileScanTask> packer = new BinPacking.ListPacker<>(maxGroupSize, 1, false); + List<List<FileScanTask>> potentialGroups = packer.pack(dataFiles, FileScanTask::length); + return potentialGroups.stream().filter(group -> + numOutputFiles(group) >= minOutputFiles && group.size() >= minInputFiles + ).collect(Collectors.toList()); + } + + private long numOutputFiles(List<FileScanTask> group) { + long groupSize = group.stream().mapToLong(FileScanTask::length).sum(); + return (long) Math.ceil((double) groupSize / targetFileSize); + } + + private void validateOptions() { + if (minFileSize >= maxFileSize) { + throw new IllegalArgumentException( Review comment: I knew I was forgetting something -- This is an automated message from the Apache Git Service. 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