poorbarcode commented on code in PR #24596: URL: https://github.com/apache/pulsar/pull/24596#discussion_r2259899284
########## pulsar-common/src/main/java/org/apache/pulsar/common/util/SingleThreadSafeScheduledExecutorService.java: ########## @@ -0,0 +1,382 @@ +/* + * 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.pulsar.common.util; + +import static java.util.concurrent.TimeUnit.NANOSECONDS; +import io.netty.util.concurrent.DefaultThreadFactory; +import java.util.concurrent.Delayed; +import java.util.concurrent.Future; +import java.util.concurrent.FutureTask; +import java.util.concurrent.RejectedExecutionHandler; +import java.util.concurrent.RunnableScheduledFuture; +import java.util.concurrent.ScheduledExecutorService; +import java.util.concurrent.ScheduledFuture; +import java.util.concurrent.ScheduledThreadPoolExecutor; +import java.util.concurrent.TimeUnit; +import java.util.concurrent.atomic.AtomicLong; +import lombok.extern.slf4j.Slf4j; + +@Slf4j +public class SingleThreadSafeScheduledExecutorService extends ScheduledThreadPoolExecutor Review Comment: > I don't think that implementing a complete ScheduledExecutorService is necessary at all. The implementation looks very complex, which isn't needed to address the problem. If you ever read the implementation of `ScheduledThreadPoolExecutor` and the internal class `ScheduledFutureTask`, you will know that the new class is very simple, which just changes the implementation of get next runtime: `setNextRunTime` > I think that we shouldn't implement the ScheduledExecutorService at all and instead make it specialized for the use case where a single task is executed with an ordinary java.lang.Thread (well it makes sense to use Netty's io.netty.util.concurrent.FastThreadLocalThread thread implementation) and with logic which calculates the Thread.sleep between task executions so that it executes at fixed rate, preventing the backlogging of the single task that it can execute. The current implementation does this -- 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]
