chaoqin-li1123 commented on code in PR #41099: URL: https://github.com/apache/spark/pull/41099#discussion_r1206244555
########## sql/core/src/main/scala/org/apache/spark/sql/execution/streaming/state/StateStoreChangelog.scala: ########## @@ -0,0 +1,178 @@ +/* + * 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.spark.sql.execution.streaming.state + +import java.io.{DataInputStream, DataOutputStream, FileNotFoundException, IOException} + +import scala.util.control.NonFatal + +import com.google.common.io.ByteStreams +import org.apache.commons.io.IOUtils +import org.apache.hadoop.fs.{FSError, Path} + +import org.apache.spark.internal.Logging +import org.apache.spark.io.CompressionCodec +import org.apache.spark.sql.execution.streaming.CheckpointFileManager +import org.apache.spark.sql.execution.streaming.CheckpointFileManager.CancellableFSDataOutputStream + +/** + * Write changes to the key value state store instance to a changelog file. + * There are 2 types of records, put and delete. + * A put record is written as: | key length | key content | value length | value content | + * A delete record is written as: | key length | key content | -1 | + * Write an Int -1 to signal the end of file. + * The overall changelog format is: | put record | delete record | ... | put record | -1 | + */ +class StateStoreChangelogWriter(fm: CheckpointFileManager, file: Path, + compressionCodec: CompressionCodec) extends Logging { + + private def compressStream(outputStream: DataOutputStream): DataOutputStream = { + val compressed = compressionCodec.compressedOutputStream(outputStream) + new DataOutputStream(compressed) + } + + private var backingFileStream: CancellableFSDataOutputStream = + fm.createAtomic(file, overwriteIfPossible = true) + private var compressedStream: DataOutputStream = compressStream(backingFileStream) + var size = 0 + + def put(key: Array[Byte], value: Array[Byte]): Unit = { + assert(compressedStream != null) + compressedStream.writeInt(key.size) + compressedStream.write(key) + compressedStream.writeInt(value.size) + compressedStream.write(value) + size += 1 + } + + def delete(key: Array[Byte]): Unit = { + assert(compressedStream != null) + compressedStream.writeInt(key.size) + compressedStream.write(key) + // -1 in the value field means record deletion. + compressedStream.writeInt(-1) + size += 1 + } + + def abort(): Unit = { + try { + if (backingFileStream != null) backingFileStream.cancel() + if (compressedStream != null) IOUtils.closeQuietly(compressedStream) + } catch { + // Closing the compressedStream causes the stream to write/flush flush data into the + // rawStream. Since the rawStream is already closed, there may be errors. + // Usually its an IOException. However, Hadoop's RawLocalFileSystem wraps + // IOException into FSError. + case e: FSError if e.getCause.isInstanceOf[IOException] => + case NonFatal(ex) => + logInfo(s"Failed to cancel changelog file $file for state store provider " + + s"with exception=$ex") + } finally { + backingFileStream = null + compressedStream = null + } + } + + def commit(): Unit = { + try { + // -1 in the key length field mean EOF. + compressedStream.writeInt(-1) + compressedStream.close() + } catch { + case e: Throwable => + abort() + logError(s"Fail to commit changelog file $file because of exception $e") + throw e + } finally { + backingFileStream = null + compressedStream = null + } + } +} + + +/** + * Read an iterator of change record from the changelog file. + * A record is represented by ByteArrayPair(key: Array[Byte], value: Array[Byte]) + * A put record is returned as a ByteArrayPair(key, value) + * A delete record is return as a ByteArrayPair(key, null) + */ +class StateStoreChangelogReader(fm: CheckpointFileManager, fileToRead: Path, + compressionCodec: CompressionCodec) + extends Iterator[ByteArrayPair] with Logging { Review Comment: Thanks for reminding! I simplify the logic with NextIterator, PTAL. -- 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] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
