cmccabe commented on a change in pull request #9998: URL: https://github.com/apache/kafka/pull/9998#discussion_r569633608
########## File path: metadata/src/main/java/org/apache/kafka/metadata/MetadataRecordSerde.java ########## @@ -0,0 +1,62 @@ +/* + * 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.kafka.metadata; + +import org.apache.kafka.common.metadata.MetadataRecordType; +import org.apache.kafka.common.protocol.ApiMessage; +import org.apache.kafka.common.protocol.ObjectSerializationCache; +import org.apache.kafka.common.protocol.Readable; +import org.apache.kafka.common.protocol.Writable; +import org.apache.kafka.common.utils.ByteUtils; +import org.apache.kafka.raft.RecordSerde; + +public class MetadataRecordSerde implements RecordSerde<ApiMessageAndVersion> { + + @Override + public ObjectSerializationCache newWriteContext() { + return new ObjectSerializationCache(); + } + + @Override + public int recordSize(ApiMessageAndVersion data, Object context) { + ObjectSerializationCache serializationCache = (ObjectSerializationCache) context; + int size = 0; + size += ByteUtils.sizeOfUnsignedVarint(data.message().apiKey()); + size += ByteUtils.sizeOfUnsignedVarint(data.version()); + size += data.message().size(serializationCache, data.version()); + return size; + } + + @Override + public void write(ApiMessageAndVersion data, Object context, Writable out) { + ObjectSerializationCache serializationCache = (ObjectSerializationCache) context; + out.writeUnsignedVarint(data.message().apiKey()); + out.writeUnsignedVarint(data.version()); + data.message().write(out, serializationCache, data.version()); + } + + @Override + public ApiMessageAndVersion read(Readable input, int size) { + short apiKey = (short) input.readUnsignedVarint(); + short version = (short) input.readUnsignedVarint(); Review comment: It is a big savings overall, right? 2 bytes per record, for every record. We use varints in the record format for the same reasons. Actually the question that @hachikuji raised earlier was whether we should have a third varint which comes first for message frame version, which is not unreasonable. ---------------------------------------------------------------- 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. For queries about this service, please contact Infrastructure at: us...@infra.apache.org
