attilapiros commented on code in PR #50230: URL: https://github.com/apache/spark/pull/50230#discussion_r2070942000
########## core/src/main/java/org/apache/spark/shuffle/checksum/RowBasedChecksum.scala: ########## @@ -0,0 +1,114 @@ +/* + * 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.shuffle.checksum + +import java.io.ObjectOutputStream +import java.util.zip.Checksum + +import scala.util.control.NonFatal + +import org.apache.spark.internal.Logging +import org.apache.spark.network.shuffle.checksum.ShuffleChecksumHelper +import org.apache.spark.util.MyByteArrayOutputStream + +/** + * A class for computing checksum for input (key, value) pairs. The checksum is independent of + * the order of the input (key, value) pairs. It is done by computing a checksum for each row + * first, and then computing the XOR for all the row checksums. + */ +abstract class RowBasedChecksum() extends Serializable with Logging { + private var hasError: Boolean = false + private var checksumValue: Long = 0 + /** Returns the checksum value computed. Tt returns the default checksum value (0) if there + * are any errors encountered during the checksum computation. + */ + def getValue: Long = { + if (!hasError) checksumValue else 0 + } + + /** Updates the row-based checksum with the given (key, value) pair */ + def update(key: Any, value: Any): Unit = { + if (!hasError) { + try { + val rowChecksumValue = calculateRowChecksum(key, value) + checksumValue = checksumValue ^ rowChecksumValue + } catch { + case NonFatal(e) => + logError("Checksum computation encountered error: ", e) + hasError = true + } + } + } + + /** Computes and returns the checksum value for the given (key, value) pair */ + protected def calculateRowChecksum(key: Any, value: Any): Long +} + +/** + * A Concrete implementation of RowBasedChecksum. The checksum for each row is + * computed by first converting the (key, value) pair to byte array using OutputStreams, + * and then computing the checksum for the byte array. + * Note that this checksum computation is very expensive, and it is used only in tests + * in the core component. A much cheaper implementation of RowBasedChecksum is in + * UnsafeRowChecksum. + * + * @param checksumAlgorithm the algorithm used for computing checksum. + */ +class OutputStreamRowBasedChecksum(checksumAlgorithm: String) + extends RowBasedChecksum() { + + private val DEFAULT_INITIAL_SER_BUFFER_SIZE = 32 * 1024 + + @transient private lazy val serBuffer = + new MyByteArrayOutputStream(DEFAULT_INITIAL_SER_BUFFER_SIZE) + @transient private lazy val objOut = new ObjectOutputStream(serBuffer) + + @transient + protected lazy val checksum: Checksum = + ShuffleChecksumHelper.getChecksumByAlgorithm(checksumAlgorithm) + + override protected def calculateRowChecksum(key: Any, value: Any): Long = { + assert(checksum != null, "Checksum is null") + + // Converts the (key, value) pair into byte array. + objOut.reset() + serBuffer.reset() + objOut.writeObject((key, value)) + objOut.flush() + serBuffer.flush() + + // Computes and returns the checksum for the byte array. + checksum.reset() + checksum.update(serBuffer.getBuf, 0, serBuffer.size()) + checksum.getValue + } +} + +object RowBasedChecksum { + def createPartitionRowBasedChecksums( Review Comment: oh I see the comment above: ``` Note that this checksum computation is very expensive, and it is used only in tests in the core component. A much cheaper implementation of RowBasedChecksum is in UnsafeRowChecksum. ``` And I can see your comment: > I can't use UnsafeRowChecksum.scala in the test because the test is in core, while the usaferow is in sql. So I added OutputStreamRowBasedChecksum for the tests in core. But you can move this class and object to the test code of the core module, is not it? -- 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: reviews-unsubscr...@spark.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: reviews-unsubscr...@spark.apache.org For additional commands, e-mail: reviews-h...@spark.apache.org
