java - Java线程阻塞

Question

我的 java 环境有问题。一年多以来，我一直在运行 Solr 1.3（搜索引擎），突然间我遇到了很多麻烦。我所有的线程池（250）每天都会被随机阻塞一次或两次。我没有对我的 solr 应用程序或我的 tomcat 服务器进行任何更改。

我正在运行 tomcat 5.5.25 和 Solr 1.3。当系统完全过载时，我得到了一个线程转储：

igot 像这样的 240 线程：

"http-8080-Processor1" daemon prio=10 tid=0x0000000000b2e000 nid=0x193 waiting for monitor entry [0x000000004066c000..0x000000004066cb20]
   java.lang.Thread.State: BLOCKED (on object monitor)
    at java.util.logging.StreamHandler.publish(StreamHandler.java:174)
    - waiting to lock <0x00007fe37e72b340> (a java.util.logging.ConsoleHandler)
    at java.util.logging.ConsoleHandler.publish(ConsoleHandler.java:88)
    at java.util.logging.Logger.log(Logger.java:472)
    at java.util.logging.Logger.doLog(Logger.java:494)
    at java.util.logging.Logger.log(Logger.java:517)
    at java.util.logging.Logger.info(Logger.java:1036)
    at org.apache.solr.core.SolrCore.execute(SolrCore.java:1212)
    at org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:303)
    at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:232)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
    at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
    at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
    at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
    at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
    at java.lang.Thread.run(Thread.java:619)

我们可以看到这个线程被阻塞并等待：<0x00007fe37e72b340>

真正拥有 <0x00007fe37e72b340> 的线程是这个：

"http-8080-Processor156" daemon prio=10 tid=0x0000000000df2000 nid=0x1e52 runnable [0x0000000044521000..0x0000000044521c20]
   java.lang.Thread.State: RUNNABLE
    at java.io.FileOutputStream.writeBytes(Native Method)
    at java.io.FileOutputStream.write(FileOutputStream.java:260)
    at java.io.BufferedOutputStream.write(BufferedOutputStream.java:105)
    - locked <0x00007fe37e3abcd8> (a java.io.BufferedOutputStream)
    at java.io.PrintStream.write(PrintStream.java:430)
    - locked <0x00007fe37e3abca0> (a java.io.PrintStream)
    at sun.nio.cs.StreamEncoder.writeBytes(StreamEncoder.java:202)
    at sun.nio.cs.StreamEncoder.implFlushBuffer(StreamEncoder.java:272)
    at sun.nio.cs.StreamEncoder.implFlush(StreamEncoder.java:276)
    at sun.nio.cs.StreamEncoder.flush(StreamEncoder.java:122)
    - locked <0x00007fe37e72cd90> (a java.io.OutputStreamWriter)
    at java.io.OutputStreamWriter.flush(OutputStreamWriter.java:212)
    at java.util.logging.StreamHandler.flush(StreamHandler.java:225)
    - locked <0x00007fe37e72b340> (a java.util.logging.ConsoleHandler)
    at java.util.logging.ConsoleHandler.publish(ConsoleHandler.java:89)
    at java.util.logging.Logger.log(Logger.java:472)
    at java.util.logging.Logger.doLog(Logger.java:494)
    at java.util.logging.Logger.log(Logger.java:517)
    at java.util.logging.Logger.info(Logger.java:1036)
    at org.apache.solr.core.SolrCore.execute(SolrCore.java:1212)
    at org.apache.solr.servlet.SolrDispatchFilter.execute(SolrDispatchFilter.java:303)
    at org.apache.solr.servlet.SolrDispatchFilter.doFilter(SolrDispatchFilter.java:232)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:215)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:188)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:172)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:127)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:117)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:108)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:151)
    at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:874)
    at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:665)
    at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:528)
    at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:81)
    at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:689)
    at java.lang.Thread.run(Thread.java:619)

这是我的线程转储的最后一部分：

"ContainerBackgroundProcessor[StandardEngine[Catalina]]" daemon prio=10 tid=0x00007f6510349800 nid=0xbff waiting on condition [0x0000000041d8d000..0x0000000041d8dd20]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
    at java.lang.Thread.sleep(Native Method)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1548)
    at java.lang.Thread.run(Thread.java:619)

"pool-1-thread-1" prio=10 tid=0x0000000000c26400 nid=0xbfe waiting on condition [0x000000004200e000..0x000000004200eca0]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00007f651b275510> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:158)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:1925)
    at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:358)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:946)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:906)
    at java.lang.Thread.run(Thread.java:619)

"Low Memory Detector" daemon prio=10 tid=0x00007f6510004400 nid=0xbfa runnable [0x0000000000000000..0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"CompilerThread1" daemon prio=10 tid=0x00007f6510001000 nid=0xbf9 waiting on condition [0x0000000000000000..0x0000000040d5e340]
   java.lang.Thread.State: RUNNABLE

"CompilerThread0" daemon prio=10 tid=0x00000000006bc400 nid=0xbf8 waiting on condition [0x0000000000000000..0x0000000040c5d2d0]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" daemon prio=10 tid=0x00000000006bb000 nid=0xbf7 runnable [0x0000000000000000..0x0000000040b5da30]
   java.lang.Thread.State: RUNNABLE

"Finalizer" daemon prio=10 tid=0x0000000000690c00 nid=0xbf6 in Object.wait() [0x000000004065e000..0x000000004065ed20]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00007f651aa10258> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:116)
    - locked <0x00007f651aa10258> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:132)
    at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:159)

"Reference Handler" daemon prio=10 tid=0x000000000068f400 nid=0xbf5 in Object.wait() [0x000000004055d000..0x000000004055dca0]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00007f651aa10338> (a java.lang.ref.Reference$Lock)
    at java.lang.Object.wait(Object.java:485)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:116)
    - locked <0x00007f651aa10338> (a java.lang.ref.Reference$Lock)

"main" prio=10 tid=0x0000000000622400 nid=0xbeb runnable [0x0000000000000000..0x00007fff69fcbba0]
   java.lang.Thread.State: RUNNABLE

"VM Thread" prio=10 tid=0x000000000068a000 nid=0xbf4 runnable 

"GC task thread#0 (ParallelGC)" prio=10 tid=0x000000000062cc00 nid=0xbec runnable 

"GC task thread#1 (ParallelGC)" prio=10 tid=0x000000000062e000 nid=0xbed runnable 

"GC task thread#2 (ParallelGC)" prio=10 tid=0x000000000062f400 nid=0xbee runnable 

"GC task thread#3 (ParallelGC)" prio=10 tid=0x0000000000630400 nid=0xbef runnable 

"GC task thread#4 (ParallelGC)" prio=10 tid=0x0000000000631800 nid=0xbf0 runnable 

"GC task thread#5 (ParallelGC)" prio=10 tid=0x0000000000632c00 nid=0xbf1 runnable 

"GC task thread#6 (ParallelGC)" prio=10 tid=0x0000000000634000 nid=0xbf2 runnable 

"GC task thread#7 (ParallelGC)" prio=10 tid=0x0000000000635400 nid=0xbf3 runnable 

"VM Periodic Task Thread" prio=10 tid=0x00007f6510006800 nid=0xbfb waiting on condition 

JNI global references: 1201

我知道这不是线程死锁问题，因为一个线程实际上正在运行所有其他线程想要的所有资源。

任何人都知道什么会导致这个问题？

score 5 · Accepted Answer

你所有的线程都在记录东西。他们都需要时不时地写在磁盘上。每次您的 240 个线程中的一个到达日志记录行时，都会出现磁盘访问问题。

令我感到困惑的是，拥有锁的线程处于 RUNNABLE 状态。

我认为它可能正在等待一些外部资源被释放（例如磁盘访问）

您的磁盘空间不足吗？您最近是否更改了存储系统中的某些内容？

score 5 · Accepted Answer

如果您在 Windows 下运行并且 java 应用程序启动控制台，请注意不要单击 DOS 框。窗口的蹩脚标记和复制“功能”块输出到 ConsoleHandler。所以任何试图写入屏幕的记录器都会被阻塞。写入控制台是在本机调用中完成的，因此当 java 线程实际上被阻塞时，它似乎处于 RUNNING 状态，只是没有办法将该阻塞状态反馈给应用程序（因为你在本地空间）。

如果应用程序被阻止（您在 DOS 框中单击），请按退出键继续。

score 0 · Accepted Answer

如果您有非常冗长的日志，那么在每条日志记录后刷新会很昂贵。

一个质量修复是清理日志，可能基于审计。

作为快速修复，覆盖StreamHandler.flush或OutputStream.flush不立即这样做。每隔一段时间只冲洗一次。但是请注意，如果您这样做，您可能会在崩溃之前立即丢失日志数据。

score 0 · Accepted Answer

我从来没有使用过java.util.logging，所以我不知道我的建议是否有用，但无论如何：
尝试使用不同的实例java.util.logging.Logger，所以并非所有 240 个线程都会在同一个监视器上被阻塞
（如果不同的实例Logger使用不同的实例，这将有所帮助java.util.logging.ConsoleHandler) .

score 0 · Accepted Answer

似乎拥有“0x00007fe37e72b340”的线程在 IO 级别被阻塞。也许是磁盘（RAID？）问题？

你能在 5 分钟后做一个线程转储，看看同一个线程是否仍然被阻塞？

score 0 · Accepted Answer

根据您的日志，问题涉及 java.util.logging.ConsoleHandler 的使用。

首先尝试通过从“${TOMCAT_HOME}/conf/logging.properties”中的“handlers”和“.handlers”列表中删除控制台处理程序来禁用它。查看问题是否仍然存在。

如果这有帮助，那么肯定是 ConsoleHandler 的输出存在问题。尝试检查“catalina.out”文件是否存在问题。这是 tomcat 将其控制台输出重定向到的文件。

java - Java线程阻塞

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