liuzqt commented on code in PR #38064: URL: https://github.com/apache/spark/pull/38064#discussion_r993738130
########## core/src/main/scala/org/apache/spark/serializer/SerializerHelper.scala: ########## @@ -0,0 +1,45 @@ +/* + * 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.serializer + +import java.nio.ByteBuffer + +import scala.reflect.ClassTag + +import org.apache.spark.internal.Logging +import org.apache.spark.util.io.{ChunkedByteBuffer, ChunkedByteBufferOutputStream} + +private[spark] object SerializerHelper extends Logging { + def serializeToChunkedBuffer[T: ClassTag]( + serializerInstance: SerializerInstance, + t: T): ChunkedByteBuffer = { + val cbbos = new ChunkedByteBufferOutputStream(1024 * 1024, ByteBuffer.allocate) Review Comment: Actually no specific reason for choosing this value, just search around `new ChunkedByteBufferOutputStream` usage, found some `1024 * 1024` in serialize manager and map output tracker, so thought it might be a reasonable value to use. Smaller size would be good for small task result, while larger chunk size is good at reducing memory fragment in case of large result but a waste for small result. Also see my comment [below](https://github.com/apache/spark/pull/38064/#issuecomment-1276518707)(just added) about some thoughts on performance -- 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]
