tomcat中有100个线程TIMED_WAITING,导致它在线程总数超过200时停止

Question

最近我们的一个生产tomcat服务器没有响应,因为tomcat的繁忙线程高达200.当我们在重新启动之前进行线程转储时,我们在TIMED_WAITING状态下获得了100个线程,就像这3个线程一样:

""http-bio-7007"-exec-241" daemon prio=10 tid=0x00002aaab107b000 nid=0x59df waiting on condition [0x0000000051239000]
java.lang.Thread.State: TIMED_WAITING (parking)
   at sun.misc.Unsafe.park(Native Method)
   - parking to wait for  <0x0000000580d877d0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
   at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2025)
   at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:424)
   at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:86)
   at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:32)
   at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:945)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
   at java.lang.Thread.run(Thread.java:662)

""http-bio-7007"-exec-237" daemon prio=10 tid=0x00002aaab186e000 nid=0x596d waiting on condition [0x000000004d1f9000]
java.lang.Thread.State: TIMED_WAITING (parking)
   at sun.misc.Unsafe.park(Native Method)
   - parking to wait for  <0x0000000580d877d0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
   at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2025)
   at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:424)
   at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:86)
   at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:32)
   at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:945)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
   at java.lang.Thread.run(Thread.java:662)

""http-bio-7007"-exec-236" daemon prio=10 tid=0x00002aaab1118000 nid=0x596c waiting on condition [0x000000004e50c000]
java.lang.Thread.State: TIMED_WAITING (parking)
   at sun.misc.Unsafe.park(Native Method)
   - parking to wait for  <0x0000000580d877d0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
   at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:198)
   at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2025)
   at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:424)
   at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:86)
   at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:32)
   at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:945)
   at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:907)
   at java.lang.Thread.run(Thread.java:662)

我们有4个应用程序的线程池(例如pool-4-thread-20等),每个线程池有20个线程,所以我不确定这100个线程在等待哪个阻塞队列？我们正在使用c3P0连接池和hibernate,这似乎不是原因.

知道java.util.concurrent.locks.AbstractQueuedSynchronizer $ ConditionObject是什么？

Answer 1

当我们修复了由c3p0管理的数据库连接泄漏时修复了这个问题.有在我们的代码少流,我们并没有在finally块关闭实体管理器之前调用回退()特别是在catch块,所以在异常连接的情况下没有回来汇集,如果异常的频率高(比大小更在超时间隔内的池)然后所有其他进程线程将堆积起来以获得连接.

Answer 2

知道java.util.concurrent.locks.AbstractQueuedSynchronizer $ ConditionObject是什么吗？

ConditionObject用于队列内部，以同步不同线程对队列的访问。

当executerpool的线程空闲并等待新任务时，它是标准的stacktrace。