rdblue commented on a change in pull request #796: URL: https://github.com/apache/iceberg/pull/796#discussion_r445920758
########## File path: core/src/main/java/org/apache/iceberg/Snapshots.java ########## @@ -0,0 +1,226 @@ +/* + * 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; + +import java.util.List; +import java.util.Map; +import java.util.stream.Collectors; +import org.apache.iceberg.expressions.Expression; +import org.apache.iceberg.expressions.Expressions; +import org.apache.iceberg.io.CloseableIterable; +import org.apache.iceberg.io.FileIO; +import org.apache.iceberg.relocated.com.google.common.collect.ImmutableList; +import org.apache.iceberg.relocated.com.google.common.collect.Iterables; +import org.apache.iceberg.relocated.com.google.common.collect.Lists; +import org.apache.iceberg.util.Pair; + +public class Snapshots { + private Snapshots() { + } + + public static MicroBatchBuilder from(Snapshot snapshot, FileIO io) { + return new MicroBatchBuilder(snapshot, io); + } + + public static class MicroBatch { + private final long snapshotId; + private final int startFileIndex; + private final int endFileIndex; + private final long sizeInBytes; + private final CloseableIterable<FileScanTask> tasks; + private final boolean lastIndexOfSnapshot; + + private MicroBatch(long snapshotId, int startFileIndex, int endFileIndex, long sizeInBytes, + CloseableIterable<FileScanTask> tasks, boolean lastIndexOfSnapshot) { + this.snapshotId = snapshotId; + this.startFileIndex = startFileIndex; + this.endFileIndex = endFileIndex; + this.sizeInBytes = sizeInBytes; + this.tasks = tasks; + this.lastIndexOfSnapshot = lastIndexOfSnapshot; + } + + public long snapshotId() { + return snapshotId; + } + + public int startFileIndex() { + return startFileIndex; + } + + public int endFileIndex() { + return endFileIndex; + } + + public long sizeInBytes() { + return sizeInBytes; + } + + public CloseableIterable<FileScanTask> tasks() { + return tasks; + } + + public boolean lastIndexOfSnapshot() { + return lastIndexOfSnapshot; + } + } + + public static class MicroBatchBuilder { + private final Snapshot snapshot; + private final FileIO io; + private Expression rowFilter; + private boolean caseSensitive; + private Map<Integer, PartitionSpec> specsById; + + private MicroBatchBuilder(Snapshot snapshot, FileIO io) { + this.snapshot = snapshot; + this.io = io; + this.rowFilter = Expressions.alwaysTrue(); + this.caseSensitive = true; + } + + public MicroBatchBuilder caseSensitive(boolean sensitive) { + this.caseSensitive = sensitive; + return this; + } + + public MicroBatchBuilder filter(Expression newRowFilter) { + this.rowFilter = newRowFilter; + return this; + } + + public MicroBatchBuilder specsById(Map<Integer, PartitionSpec> specs) { + this.specsById = specs; + return this; + } + + public MicroBatch generate(int startFileIndex, long targetSizeInBytes, boolean isStarting) { + List<ManifestFile> manifests = isStarting ? snapshot.dataManifests() : + snapshot.dataManifests().stream().filter(m -> m.snapshotId().equals(snapshot.snapshotId())) + .collect(Collectors.toList()); + + List<Pair<ManifestFile, Integer>> manifestIndexes = indexManifests(manifests); + List<Pair<ManifestFile, Integer>> skippedManifestIndexes = skipManifests(manifestIndexes, startFileIndex); + + return generateMicroBatch(skippedManifestIndexes, startFileIndex, targetSizeInBytes, isStarting); + } + + private List<Pair<ManifestFile, Integer>> indexManifests(List<ManifestFile> manifestFiles) { + int currentFileIndex = 0; + List<Pair<ManifestFile, Integer>> manifestIndexes = Lists.newArrayList(); + + for (ManifestFile manifest : manifestFiles) { + int filesCount = manifest.addedFilesCount() + manifest.existingFilesCount(); + manifestIndexes.add(Pair.of(manifest, currentFileIndex)); + currentFileIndex += filesCount; + } + + return manifestIndexes; + } + + private List<Pair<ManifestFile, Integer>> skipManifests(List<Pair<ManifestFile, Integer>> indexedManifests, + int startFileIndex) { + if (startFileIndex == 0) { + return indexedManifests; + } + + int index = 0; + for (Pair<ManifestFile, Integer> manifest : indexedManifests) { + if (manifest.second() > startFileIndex) { + break; + } + + index++; + } + + return indexedManifests.subList(index - 1, indexedManifests.size()); + } + + private MicroBatch generateMicroBatch(List<Pair<ManifestFile, Integer>> indexedManifests, + int startFileIndex, long targetSizeInBytes, boolean isStarting) { + if (indexedManifests.isEmpty()) { + return new MicroBatch(snapshot.snapshotId(), startFileIndex, startFileIndex + 1, 0L, + CloseableIterable.empty(), true); + } + + long currentSizeInBytes = 0L; + int currentFileIndex = 0; + List<CloseableIterable<FileScanTask>> batchTasks = Lists.newArrayList(); + + for (Pair<ManifestFile, Integer> pair : indexedManifests) { + currentFileIndex = pair.second(); Review comment: One more thing to note: it's a little odd at first that this also requires keeping track of the next offset and whether the manifest was exhausted. ---------------------------------------------------------------- This is an automated message from the Apache Git Service. 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