zentol commented on code in PR #3: URL: https://github.com/apache/flink-connector-cassandra/pull/3#discussion_r1104612653
########## flink-connector-cassandra/src/main/java/org/apache/flink/connector/cassandra/source/enumerator/CassandraEnumeratorStateSerializer.java: ########## @@ -0,0 +1,81 @@ +/* + * 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.connector.cassandra.source.enumerator; + +import org.apache.flink.connector.cassandra.source.split.CassandraSplit; +import org.apache.flink.connector.cassandra.source.split.CassandraSplitSerializer; +import org.apache.flink.core.io.SimpleVersionedSerializer; +import org.apache.flink.core.memory.DataInputDeserializer; +import org.apache.flink.core.memory.DataOutputSerializer; + +import java.io.IOException; +import java.util.ArrayDeque; +import java.util.Queue; + +/** Serializer for {@link CassandraEnumeratorState}. */ +public class CassandraEnumeratorStateSerializer + implements SimpleVersionedSerializer<CassandraEnumeratorState> { + + public static final CassandraEnumeratorStateSerializer INSTANCE = + new CassandraEnumeratorStateSerializer(); + private static final ThreadLocal<DataOutputSerializer> SERIALIZER_CACHE = + ThreadLocal.withInitial(() -> new DataOutputSerializer(64)); Review Comment: This is overkill for the enumerator state. In contrast to splits (of which there can be thousands...[hmm](https://github.com/apache/flink-connector-cassandra/pull/3#discussion_r1104624477)) there's only 1 state at all times. Fun fact about thread locals: They can easily leak the user-code classloader. If any thread that out-lives the task (like say, a shared thread pool) ever accesses the ThreadLocal, then the thread retains a reference to the thread local, due to which it can't be GC'd. Just thought I'd throw this out there. -- 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]
