Zakelly commented on code in PR #22590: URL: https://github.com/apache/flink/pull/22590#discussion_r1223784984
########## flink-runtime/src/main/java/org/apache/flink/runtime/checkpoint/filemerging/LogicalFile.java: ########## @@ -0,0 +1,127 @@ +/* + * 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.flink.runtime.checkpoint.filemerging; + +import org.apache.flink.annotation.VisibleForTesting; +import org.apache.flink.core.fs.Path; +import org.apache.flink.util.StringBasedID; + +import javax.annotation.Nonnull; +import javax.annotation.Nullable; + +import java.io.IOException; +import java.util.UUID; + +import static org.apache.flink.runtime.checkpoint.filemerging.FileMergingSnapshotManager.SubtaskKey; + +/** An abstraction of logical files in file-merging checkpoints. */ +public class LogicalFile { + + /** ID for {@link LogicalFile}. It should be unique for each file. */ + public static class LogicalFileId extends StringBasedID { + + public LogicalFileId(String keyString) { + super(keyString); + } + + public Path getFilePath() { + return new Path(getKeyString()); + } + + public static LogicalFileId generateRandomId() { + return new LogicalFileId(UUID.randomUUID().toString()); + } + } + + /** ID for this file. */ + LogicalFileId fileId; + + private long lastCheckpointId = -1L; + + boolean removed = false; + + /** The physical file where this logical file is stored. This should be null. */ + @Nonnull private final PhysicalFile physicalFile; + + @Nonnull private final SubtaskKey subtaskKey; + + public LogicalFile( + LogicalFileId fileId, + @Nonnull PhysicalFile physicalFile, + @Nonnull SubtaskKey subtaskKey) { + this.fileId = fileId; + this.physicalFile = physicalFile; + this.subtaskKey = subtaskKey; + physicalFile.incRefCount(); + } + + public LogicalFileId getFileId() { + return fileId; + } + + public void discardWithCheckpointId(long checkpointId) throws IOException { + if (!removed && checkpointId >= lastCheckpointId) { + physicalFile.decRefCount(); + removed = true; + } + } + + public void advanceLastCheckpointId(long checkpointId) { Review Comment: I added JavaDocs to explain this method. In short, the value `lastUsedCheckpointId` acts pretty much like the `lastUsedCheckpointID` in `SharedStateEntry`. It is a watermark mechanism to record the last checkpoint that uses this logical file, to determine whether to delete a logical file when a cp is subsumed or aborted. For those two questions: 1. No, a logical file is a shared state file before merging, it may shared across checkpoints. 2. When a file is used/reused by a checkpoint, this method is called. -- 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: issues-unsubscr...@flink.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
