Samrat002 commented on code in PR #27187: URL: https://github.com/apache/flink/pull/27187#discussion_r2808984926
########## flink-filesystems/flink-s3-fs-native/src/main/java/org/apache/flink/fs/s3native/writer/NativeS3RecoverableFsDataOutputStream.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.flink.fs.s3native.writer; + +import org.apache.flink.core.fs.RecoverableFsDataOutputStream; +import org.apache.flink.core.fs.RecoverableWriter; +import org.apache.flink.fs.s3native.writer.NativeS3Recoverable.PartETag; + +import java.io.File; +import java.io.FileOutputStream; +import java.io.IOException; +import java.nio.file.Files; +import java.util.ArrayList; +import java.util.Collections; +import java.util.List; +import java.util.UUID; +import java.util.concurrent.atomic.AtomicInteger; + +public class NativeS3RecoverableFsDataOutputStream extends RecoverableFsDataOutputStream { + + private final NativeS3AccessHelper s3AccessHelper; + private final String key; + private final String uploadId; + private final String localTmpDir; + private final long minPartSize; + + private final List<PartETag> completedParts; + private long numBytesInParts; + + private File currentTempFile; + private FileOutputStream currentOutputStream; + private long currentPartSize; + private final AtomicInteger nextPartNumber; + + private volatile boolean closed; + + public NativeS3RecoverableFsDataOutputStream( + NativeS3AccessHelper s3AccessHelper, + String key, + String uploadId, + String localTmpDir, + long minPartSize) + throws IOException { + this(s3AccessHelper, key, uploadId, localTmpDir, minPartSize, new ArrayList<>(), 0L); + } + + public NativeS3RecoverableFsDataOutputStream( Review Comment: Good catch. You're right that synchronizedList + AtomicInteger gave a misleading impression of thread safety while the remaining mutable state (numBytesInParts, currentPartSize, currentTempFile, currentOutputStream) was unguarded. I've reworked this to align with the existing S3RecoverableFsDataOutputStream in flink-s3-fs-base Added @NotThreadSafe annotation and documented that all write operations are confined to the single Flink operator thread (consistent with RecoverableFsDataOutputStream contract) 1. Replaced Collections.synchronizedList with plain ArrayList and AtomicInteger with plain int — these gave a false sense of thread safety while the class wasn't actually safe for concurrent writes 2. Added a ReentrantLock guarding only close(), closeForCommit(), and persist() — the one legitimate concurrent scenario where the Flink runtime calls close() from a cancellation thread while the operator thread is in persist() or closeForCommit(). The lock is not on the hot write() / flush() path, so there's zero performance impact during normal operation. -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected]
