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在Tomcat8中，java请求在高峰时间占用太多时间

11 月，2 周 Questions & Answers

我已经用以下配置配置了tomcat：

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
           maxThreads="500"
           maxConnections="20000"
           acceptCount="150"
           etc... />

对于AJP连接器，maxThreads=500和acceptCount="150"的编号相同

它在大多数情况下都能正常工作，但在高峰时间，当我收到的请求比平时多得多时，响应时间太长。有时超过15秒，偶尔超时。看起来还可以，因为maxThreads=500我有几千个请求，但是，在服务器状态下，我看到：

Max threads: 500 Current thread count: 17 Current thread busy: 1 Keep alive sockets count: 1

到目前为止，我看到的currentThreadCount的最大数量是27个。如果有这么多连接，tomcat不应该创建更多线程（最多500个）以更快响应吗

那么，我做错了什么？我错过了什么？我有2核CPU（高峰时段的最大使用量~10%）和2GB内存（最大使用量60%）

关于web应用的简短信息：通常，每个用户每个会话至少发出2个请求：静态JSON响应和1个数据库查询。在高峰期，我有15-20k活跃用户，但我不知道每秒能收到多少请求。然而，5k活跃用户的反应很慢

我还增加了应用程序属性上的最大活动连接数，而当前应用程序的性能没有变化。属性：

spring.jpa.hibernate.ddl-auto=update
spring.datasource.driverClassName=com.mysql.jdbc.Driver
spring.datasource.url=jdbc:mysql://localhost:3306/database_name
spring.datasource.username=$username$
spring.datasource.password=$password$
spring.datasource.tomcat.max-active=200
spring.datasource.tomcat.max-wait=10000
spring.datasource.tomcat.max-idle=50
spring.datasource.tomcat.min-idle=10
spring.datasource.tomcat.initial-size=10

更新 我使用以下配置将默认的JDBC连接池更改为Hikari，并启用了jta，但是在高峰时间没有感觉到任何差异：

spring.jta.enabled=true
spring.datasource.hikari.maximum-pool-size=125
spring.datasource.hikari.minimum-idle=5

我在下面添加数据库查询。查询结果后来添加到另一个对象中，并作为ResponseBy返回

@Query("select new ObjectClass(s.id, s.a, s.b, s.c") from TableName s " +
        "where s.x > :param order by id desc")
List<ObjectClass> getObjects(@Param("param") long param);

CPU使用率没有增长，RAM几乎有一半空闲，如果我有太多的请求，我不应该在服务器上超载吗？相反，我的响应时间很慢。因此，我想我有一个配置问题，我想解决

-Xms512M -Xmx1024M

JVM

在高峰时间挂起的应用程序：

Active sessions: 3243 Session count: 475330 Max active sessions: 4685 Rejected session creations: 0 Expired sessions: 472105 Longest session alive time: 7457 s Average session alive time: 9 s Processing time: 3177 ms JSPs loaded: 0 JSPs reloaded: 0

堆栈跟踪：

"Attach Listener" #502 daemon prio=9 os_prio=0 tid=0x00007fde58007800 nid=0x3ff waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Abandoned connection cleanup thread" #69 daemon prio=5 os_prio=0 tid=0x00007fde6c03e800 nid=0xa44 in Object.wait() [0x00007fde471ba000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
    - locked <0x00000000c259e618> (a java.lang.ref.ReferenceQueue$Lock)
    at com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:64)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-exec-25" #68 daemon prio=5 os_prio=0 tid=0x00007fde40016000 nid=0x741 waiting on condition [0x00007fde35fe0000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000c1cc6758> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:85)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:31)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-exec-11" #54 daemon prio=5 os_prio=0 tid=0x00007fde38041800 nid=0x733 waiting on condition [0x00007fde36fee000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000c1cc6758> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:85)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:31)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-AsyncTimeout" #52 daemon prio=5 os_prio=0 tid=0x00007fde884e8800 nid=0x732 waiting on condition [0x00007fde370ef000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
    at java.lang.Thread.sleep(Native Method)
    at org.apache.coyote.AbstractProtocol$AsyncTimeout.run(AbstractProtocol.java:1211)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-Acceptor-0" #51 daemon prio=5 os_prio=0 tid=0x00007fde884e6800 nid=0x731 runnable [0x00007fde371f0000]
   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
    at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)
    at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)
    - locked <0x00000000c019d7e8> (a java.lang.Object)
    at org.apache.tomcat.util.net.NioEndpoint$Acceptor.run(NioEndpoint.java:455)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-ClientPoller-1" #50 daemon prio=5 os_prio=0 tid=0x00007fde884e4800 nid=0x730 runnable [0x00007fde372f1000]
   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
    at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
    at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)
    at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
    - locked <0x00000000c1da2fa0> (a sun.nio.ch.Util$3)
    - locked <0x00000000c1da2f90> (a java.util.Collections$UnmodifiableSet)
    - locked <0x00000000c1d5b1e0> (a sun.nio.ch.EPollSelectorImpl)
    at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
    at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:787)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-ClientPoller-0" #49 daemon prio=5 os_prio=0 tid=0x00007fde884d6000 nid=0x72f runnable [0x00007fde373f2000]
   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
    at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
    at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)
    at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
    - locked <0x00000000c1d510d8> (a sun.nio.ch.Util$3)
    - locked <0x00000000c1d510c8> (a java.util.Collections$UnmodifiableSet)
    - locked <0x00000000c1ce78c0> (a sun.nio.ch.EPollSelectorImpl)
    at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
    at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:787)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-exec-10" #48 daemon prio=5 os_prio=0 tid=0x00007fde884c7000 nid=0x72e waiting on condition [0x00007fde374f3000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000c1cc6758> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:85)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:31)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-exec-2" #40 daemon prio=5 os_prio=0 tid=0x00007fde884b7000 nid=0x726 waiting on condition [0x00007fde37cfb000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000c1cc6758> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:85)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:31)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

"ajp-nio-8009-exec-1" #39 daemon prio=5 os_prio=0 tid=0x00007fde884b5000 nid=0x725 waiting on condition [0x00007fde37dfc000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000c1cc6758> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.LinkedBlockingQueue.poll(LinkedBlockingQueue.java:467)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:85)
    at org.apache.tomcat.util.threads.TaskQueue.poll(TaskQueue.java:31)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1073)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

"http-nio-127.0.0.1-8080-AsyncTimeout" #38 daemon prio=5 os_prio=0 tid=0x00007fde884b3000 nid=0x724 waiting on condition [0x00007fde37efd000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
    at java.lang.Thread.sleep(Native Method)
    at org.apache.coyote.AbstractProtocol$AsyncTimeout.run(AbstractProtocol.java:1211)
    at java.lang.Thread.run(Thread.java:748)

"http-nio-127.0.0.1-8080-Acceptor-0" #37 daemon prio=5 os_prio=0 tid=0x00007fde884b1800 nid=0x723 runnable [0x00007fde37ffe000]
   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.ServerSocketChannelImpl.accept0(Native Method)
    at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:422)
    at sun.nio.ch.ServerSocketChannelImpl.accept(ServerSocketChannelImpl.java:250)
    - locked <0x00000000c01a03b8> (a java.lang.Object)
    at org.apache.tomcat.util.net.NioEndpoint$Acceptor.run(NioEndpoint.java:455)
    at java.lang.Thread.run(Thread.java:748)

"http-nio-127.0.0.1-8080-exec-1" #25 daemon prio=5 os_prio=0 tid=0x00007fde88324000 nid=0x717 waiting on condition [0x00007fde46db8000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000c1d9c4e0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.park(LockSupport.java:175)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(AbstractQueuedSynchronizer.java:2039)
    at java.util.concurrent.LinkedBlockingQueue.take(LinkedBlockingQueue.java:442)
    at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:103)
    at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:31)
    at java.util.concurrent.ThreadPoolExecutor.getTask(ThreadPoolExecutor.java:1074)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1134)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
    at java.lang.Thread.run(Thread.java:748)

"ContainerBackgroundProcessor[StandardEngine[Catalina]]" #24 daemon prio=5 os_prio=0 tid=0x00007fde88323000 nid=0x716 waiting on condition [0x00007fde476bb000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
    at java.lang.Thread.sleep(Native Method)
    at org.apache.catalina.core.ContainerBase$ContainerBackgroundProcessor.run(ContainerBase.java:1355)
    at java.lang.Thread.run(Thread.java:748)

"Abandoned connection cleanup thread" #22 daemon prio=5 os_prio=0 tid=0x00007fde4ca72800 nid=0x6f5 in Object.wait() [0x00007fde45c22000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
    - locked <0x00000000c102c4b0> (a java.lang.ref.ReferenceQueue$Lock)
    at com.mysql.jdbc.AbandonedConnectionCleanupThread.run(AbandonedConnectionCleanupThread.java:64)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)

"Tomcat JDBC Pool Cleaner[1595428806:1507838479700]" #21 daemon prio=5 os_prio=0 tid=0x00007fde4ca5b800 nid=0x6f4 in Object.wait() [0x00007fde470b9000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    at java.util.TimerThread.mainLoop(Timer.java:552)
    - locked <0x00000000c0f6fe80> (a java.util.TaskQueue)
    at java.util.TimerThread.run(Timer.java:505)

"NioBlockingSelector.BlockPoller-2" #13 daemon prio=5 os_prio=0 tid=0x00007fde8847e000 nid=0x66f runnable [0x00007fde478bd000]
   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
    at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
    at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)
    at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
    - locked <0x00000000c019bd40> (a sun.nio.ch.Util$3)
    - locked <0x00000000c019bd30> (a java.util.Collections$UnmodifiableSet)
    - locked <0x00000000c019bbf8> (a sun.nio.ch.EPollSelectorImpl)
    at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
    at org.apache.tomcat.util.net.NioBlockingSelector$BlockPoller.run(NioBlockingSelector.java:339)

"NioBlockingSelector.BlockPoller-1" #12 daemon prio=5 os_prio=0 tid=0x00007fde8846f800 nid=0x66e runnable [0x00007fde479be000]
   java.lang.Thread.State: RUNNABLE
    at sun.nio.ch.EPollArrayWrapper.epollWait(Native Method)
    at sun.nio.ch.EPollArrayWrapper.poll(EPollArrayWrapper.java:269)
    at sun.nio.ch.EPollSelectorImpl.doSelect(EPollSelectorImpl.java:93)
    at sun.nio.ch.SelectorImpl.lockAndDoSelect(SelectorImpl.java:86)
    - locked <0x00000000c019ec10> (a sun.nio.ch.Util$3)
    - locked <0x00000000c019ec00> (a java.util.Collections$UnmodifiableSet)
    - locked <0x00000000c019ead8> (a sun.nio.ch.EPollSelectorImpl)
    at sun.nio.ch.SelectorImpl.select(SelectorImpl.java:97)
    at org.apache.tomcat.util.net.NioBlockingSelector$BlockPoller.run(NioBlockingSelector.java:339)

"GC Daemon" #11 daemon prio=2 os_prio=0 tid=0x00007fde883f9000 nid=0x66b in Object.wait() [0x00007fde741c6000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000000c02f16d8> (a sun.misc.GC$LatencyLock)
    at sun.misc.GC$Daemon.run(GC.java:117)
    - locked <0x00000000c02f16d8> (a sun.misc.GC$LatencyLock)

"AsyncFileHandlerWriter-1510467688" #10 daemon prio=5 os_prio=0 tid=0x00007fde88168800 nid=0x63e waiting on condition [0x00007fde7475c000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x00000000c02f16e8> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
    at java.util.concurrent.locks.LockSupport.parkNanos(LockSupport.java:215)
    at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(AbstractQueuedSynchronizer.java:2078)
    at java.util.concurrent.LinkedBlockingDeque.pollFirst(LinkedBlockingDeque.java:522)
    at java.util.concurrent.LinkedBlockingDeque.poll(LinkedBlockingDeque.java:684)
    at org.apache.juli.AsyncFileHandler$LoggerThread.run(AsyncFileHandler.java:160)

"Service Thread" #7 daemon prio=9 os_prio=0 tid=0x00007fde880af000 nid=0x62e runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C1 CompilerThread1" #6 daemon prio=9 os_prio=0 tid=0x00007fde880ac000 nid=0x62d waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #5 daemon prio=9 os_prio=0 tid=0x00007fde880a9000 nid=0x62c waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" #4 daemon prio=9 os_prio=0 tid=0x00007fde880a7000 nid=0x62b runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" #3 daemon prio=8 os_prio=0 tid=0x00007fde88080000 nid=0x625 in Object.wait() [0x00007fde74f33000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:143)
    - locked <0x00000000c02f7408> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:164)
    at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:209)

"Reference Handler" #2 daemon prio=10 os_prio=0 tid=0x00007fde8807b800 nid=0x622 in Object.wait() [0x00007fde75034000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    at java.lang.Object.wait(Object.java:502)
    at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
    - locked <0x00000000c02f7490> (a java.lang.ref.Reference$Lock)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

"main" #1 prio=5 os_prio=0 tid=0x00007fde8800a800 nid=0x589 runnable [0x00007fde8f6af000]
   java.lang.Thread.State: RUNNABLE
    at java.net.PlainSocketImpl.socketAccept(Native Method)
    at java.net.AbstractPlainSocketImpl.accept(AbstractPlainSocketImpl.java:409)
    at java.net.ServerSocket.implAccept(ServerSocket.java:545)
    at java.net.ServerSocket.accept(ServerSocket.java:513)
    at org.apache.catalina.core.StandardServer.await(StandardServer.java:466)
    at org.apache.catalina.startup.Catalina.await(Catalina.java:744)
    at org.apache.catalina.startup.Catalina.start(Catalina.java:690)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:498)
    at org.apache.catalina.startup.Bootstrap.start(Bootstrap.java:355)
    at org.apache.catalina.startup.Bootstrap.main(Bootstrap.java:495)

"VM Thread" os_prio=0 tid=0x00007fde88073800 nid=0x5fd runnable 

"GC task thread#0 (ParallelGC)" os_prio=0 tid=0x00007fde8801f800 nid=0x597 runnable 

"GC task thread#1 (ParallelGC)" os_prio=0 tid=0x00007fde88021000 nid=0x598 runnable 

"VM Periodic Task Thread" os_prio=0 tid=0x00007fde880bd800 nid=0x62f waiting on condition 

JNI global references: 317

更新： 虽然我还没有解决我的问题，@Per Huss的回答把我推向了正确的方向，分别分析每一条线索并找出问题所在。我现在必须奖励我的赏金，因此，我将把它奖励给他。然而，我感谢所有在这里发表评论的人，因为所有的评论都帮助我学到了新的东西

更新2: 问题似乎出在apache内部。在高峰时间，即使是静态页面，响应时间也很慢，即使是来自其他应用程序的页面。包括tomcat manager。因此，我将prefork改为mpm_worker，目前正在测试不同的配置。我会很快用结果更新这个帖子


共 (6) 个答案

  1. # 1 楼答案

    您可以允许任意多个线程，但如果查询数量增加，RDBMS的响应时间就会缩短，这可能是您的根本原因

    你需要确定他在哪里。创建一个虚拟页面，像疯子一样从多台计算机向其发出请求。如果虚拟页面及时响应，那么您的问题与连接号无关，与数据库的关系更大。这种情况极有可能发生

    看看你的数据库，确保你的模式是正常的。此外，如果经常按某些列搜索，请确保创建了正确的索引。看看你的问题，看看它们是否太慢了。如果是这样，优化它们。缓存一些不太频繁更改的数据，并重用它们

  2. # 2 楼答案

    在这些bug中，首先我们应该确定问题所在。下面给出了调试此类问题的行动计划：

    比如你的情况

    请求来自用户对tomcat的请求，然后它会将其提供给您的应用程序

    首先，检查哪里有问题，即以下地方可能有问题：

    1. 任何应用程序api或所有api都需要时间，但tomcat线程是免费的
    2. tomcat线程不是空闲的，每个线程的处理都需要时间，因此会出现延迟
    3. 你开始花时间了
    4. 在查询数据库时，可能会有更多数据被加载到应用程序中，并出现一些java gc问题

    因此，在第一种情况下，请检查您的应用程序日志，如果没有日志，请放置日志并检查您的应用程序是否需要时间（日志从不说谎）

    在第二种情况下，检查tomcat日志，了解情况

    在第三种情况下，请检查您的数据库日志，查询是否需要更多时间

    在第四种情况下，您可以监控java运行状况监控，市场上有很多工具，比如jfr、jcisualvm等

    另外，你的问题没有足够的解释，请回答以下问题

    1. 您的应用程序的示例结构是什么
    2. 如何使应用程序恢复非正常状态，例如，重新启动是否解决了问题？ 我这样问是因为如果你需要重新启动它，那么可能会出现死锁，所以你可能需要使用jstack并对其进行分析
    3. 应用程序得到了多少XMX
    4. 数据库服务器和应用服务器在同一台机器上吗？ 因为在某些机器的高峰时间可能会出现一些io问题，所以我们需要同时检查这两个问题

    请首先确定问题在哪里，然后我们可以继续，我们如何确定和解决问题

    谢谢

  3. # 3 楼答案

    使用spring时，默认值是Tomcat。如何使用Netty、Undertow或Jetty以获得更好的性能。还请记住，尽管有一个双核CPU，但实际上并没有500个线程

    上面的答案实际上是模拟应用程序对流量的反应，这可能是最好的方法。如果使用关系数据库，请记住，写操作的速度可能比读操作慢十倍（您可以在Cassandra文档中看到一些有趣的统计数据）。如果使用hibernate，您可能还需要查找n+1问题。最好的方法是：编写一个集成测试，记录发送到数据库的sql。如果你的测试发送51而不是一个查询，那么你就有了它

  4. # 4 楼答案

    恐怕这个问题目前除了猜测之外没有足够的信息。CPU使用率低表明java进程正在等待某些东西，可能是从获取到数据库的连接、等待查询结果或其他任何东西。我会先看看是什么导致了等待，然后再尝试修复它。一种方法是跑步

    jstack <pid>

    （其中<pid>将是流程的pid）在峰值期间。它将列出每个线程的堆栈跟踪。你可以从中找出问题所在，也可以将其粘贴到问题中，或许社区可以帮助你解决问题。祝你调音好运

  5. # 5 楼答案

    我终于解决了我的问题。事实上，是apache不允许足够的连接。首先，我把prefork改为mpm worker。后来，我增加了MaxRequestWorkers的数量

    <IfModule mpm_worker_module>
    StartServers             2
    MinSpareThreads          50
    MaxSpareThreads          125
    ThreadLimit              64
    ThreadsPerChild          25
    ServerLimit              5000
    MaxRequestWorkers        5000
    MaxConnectionsPerChild   4500

    早些时候，我已经有3000个活跃用户，响应速度很慢。在新的配置下，即使17000名活跃用户也没有增加响应时间，它的工作方式与平时一样。正如预期的那样，CPU使用率和RAM在峰值时间增加，然后恢复正常

  6. # 6 楼答案

    If there are so many connections, shouldn't tomcat create more threads (up to 500) to respond faster?

    =>；根据Tomcat8文档，如果同时收到的请求超过了当前可用的请求处理线程所能处理的数量，那么将创建额外的线程，直到配置的最大值（maxThreads属性的值）。如果接收到更多的同时请求，则这些请求将堆积在连接器创建的服务器套接字中，直到配置的最大值（acceptCount属性的值）

    因此，tomcat必须根据需要创建线程。此外，Tomcat 8默认在NIO模式下工作，这意味着一个线程可以服务多个请求。您可以通过在负载测试期间启动“jvisualvm”之类的监控工具来确认该行为

    enter image description here 实时线程：这显示了当前的实时/活动线程数量，包括守护进程线程和非守护进程线程（当前正在运行）

    Live Peak：这给出了自Java虚拟机启动或峰值重置以来的Live线程峰值计数

    守护进程线程：这给出了当前活动守护进程线程的数量

    线程总数：这给出了自Java虚拟机启动以来创建和启动的线程总数

    So, what am I doing wrong? What am I missing? I have 2 core CPU (max usage during peak hours ~10%) and 2GB of RAM (max usage 60%).CPU usage doesn't grow, RAM is almost half-free if I am having too many requests, shouldn't I have overloaded on the server? Instead, I just get slow response time.

    =>；在我看来，线程在从数据库获取数据时阻塞。这可能是因为在加载期间查询的性能较差。我建议启用“hibernate.show_sql”捕获sql。检查SQL的执行计划，确保应用了索引。通过在SQL客户机上执行查询，还可以在加载期间检查查询的性能