英文:
Java thread stopping for a while
问题
我有以下问题。我有一个部署在Tomcat服务器上的Springboot Java应用程序。我正在使用SimpleAsyncTaskExecutor和@Scheduled来每隔10分钟运行一些任务。但有时执行会突然停止，一段时间后才继续，有时是2分钟，有时是10分钟，有时根本不会继续执行。
我尝试过增加Tomcat的最大内存，但没有效果。我确信这不是未捕获的异常，所以我认为可能是线程饥饿，但我该如何解决这个问题？
英文:
I've the following problem. I've a Springboot Java app deployed in a tomcat server. I'm using SimpleAsyncTaskExecutor and @Scheduled to run some tasks every 10 min. But sometimes the execution just stops, and continues after a while, sometimes 2 minutes, sometimes 10, and sometimes it just doesn't continue the execution.
I've tried increasing the tomcat max memory, but this didn't work. Im sure it's not an uncaught exception, so I think it may be thread starvation, but how can I solve this?
答案1
得分: 1
Yes, 我们能在执行冻结时获取线程转储吗？它们显示了什么？为了调试这类问题，我过去会获取一系列间隔5到10秒的5个线程转储，并使用类似https://fastthread.io/的线程转储分析工具进行分析。
英文:
Were you able to take thread dumps when the execution is frozen? What do they show? To debug issues like this, I used to take a sequence of 5 thread dumps 5 to 10 seconds apart and analyze them with some thread dump analyzer tool like https://fastthread.io/
答案2
得分: 0
如果这是线程饥饿的问题，那么你可以在方法声明中使用关键字synchronized，或者在关键代码处创建一个synchronized{}代码块。此外，你可以使用Lock，并使用lock()和unlock()方法提供的Lock。
注意：如果你使用Lock，将关键代码放在try{} finally块中，以确保始终释放内部锁。
lock.lock(); //使用锁
try {
//执行关键代码部分。
} finally {
lock.unlock(); //释放锁，以便其他线程可以使用它。
}
英文:
If it's thread starvation issue then you can use the keyword synchronizedin your method declarations or create a synchronized{} block of code wherever there is critical code . Also you can use a Lock and use .lock() and .unlock() methods provided with Lock.
Note-if you are using Lock put your critical code in a try{} finally block so you always release the intrinsic lock.
lock.lock(); //using lock
try {
//execute critical section of the code.
} finally {
lock.unlock();//release the lock so other thread can use it.
}
答案3
得分: 0
以下是翻译好的部分：
两件事可能正在发生：
- 您的线程正在等待监视器
- 垃圾收集正在执行停止-世界收集。
您可以使用 -xloggc 开关向您的应用程序添加垃圾收集日志。这样，您将对您的堆有更清晰的了解。
您还可以在线程被锁定之前、之后和同时使用 jstack 或 kill -3 来获取堆栈跟踪。您可以将此操作分别运行并将输出保存到文件中。
您还可以连接 jconsole 到您的应用程序并检查您的堆和线程。
英文:
Two things could be happening:
- your threads are waiting for monitor
- GC is doing stop-the-world collection.
You could add GC log to your application using -xloggc switch. That way you will have a better picture of your heap.
You can also take stack trace using jstack or kill -3 before , after and while the threads are locked up. You can run this separately and output to a file.
You could also connect jconsole to your application and examine your heap and threads
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