CHAP 09. 스레드 단면 잘라 놓기

자바 트러블슈팅: scouter를 활용한 시스템 장애 진단 및 해결 노하우를 챕터 9을 요약한 내용입니다.

스레드에서 발생하는 모든 문제점들을 쉽게 찾을 수 있는 도구는 많지 않다. 그중에서 데드록이 발생했거나 록이 걸려 여러 스레드가 그 록이 풀리기만을 기다리고 있을 때, 문제를 찾는 가장 좋은 방법이 바로 스레드 단면을 확인하는 것이 간단하다. 게다가 시스템의 CPU가 100%에 도달하면 대부분의 모니터링 도구가 무용지물이 되기 때문에, 스레드 단면을 만들고 이해하는 방법을 알아 두는 것은 매우 중요하다.

스레드 단면은 언제 자를까?

현재 운영 중인 시스템에 문제가 있을 때, APM 같은 도구들이 없다면 반드시 스레드 단면을 잘라 봐야 한다. 그것도 한 번으로는 부족하다. 적어도 두 번, 많으면 10~30초에 한 번씩 적어도 열번 정도는 단명을 생성해서 확인 작업을 수행해야만 한다. 스레드 단면을 분석하면 다음의 경우에 매우 빨리 원인을 찾을 수 있다.

  • 모든 시스템이 응답이 없을 때(전문가들은 시스템 행이 걸렸다고 말한다)

  • 사용자 수가 많지도 않은데, 시스템의 CPU 사용량이 떨어지지 않을 떄

  • 특정 애플리케이션을 수행했는데, 전혀 응답이 없을 때

  • 기타 여러 가지 상황에서 시스템이 내 마음대로 작동하지 않을 때

스레드 단면이 뭐길래

스레드 단면은 보통 스레드 덤프라고 한다. 스레드 덤프를 생성하는 명령어를 수행하면, 수행한 그 시점에 JVM에서 수행되고 있는 모든 스레드가 무슨 일을 하고 있는지 알 수 있다.

다음의 샘플 프로그램을 보자

public class MakeThreads {

    public static void main(String[] args) {
        for(int loop =0; loop < 3; loop++){
            LoopingThread thread  = new LoopingThread();
            thread.start();
        }
        System.out.println("Started looping threads..." + " You must stop this process after test...");
    }
}
class LoopingThread extends Thread {

    @Override
    public void run() {
        int runCount = 100;
        while (true) {
            try {
                String string = new String("AAA");
                List<String> list = new ArrayList<>(runCount);
                for(int loop =0; loop < runCount; loop++){
                    list.add(string);
                }
                Map<String, Integer> hashMap = new HashMap<>(runCount);
                for(int loop = 0; loop < runCount; loop++){
                    hashMap.put(string + loop, loop);
                }
            } catch (Exception e){
                e.printStackTrace();
            }
        }
    }
}

이제 소스를 실행해보자

> javac com/example/practice/threadDump/MakeThreads.java
> java com/example/practice/threadDump/MakeThreads

Started looping threads... You must stop this process after test...

스레드 단면 생성하기

방법은 간단하다.

  1. 클래스 파일의 결과 로그를 특정 파일에 작성한다.

    java com/example/practice/threadDump/MakeThreads > ThreadDump.txt

  2. control + \ 키를 누르면 스레드 단면을 생성 할 수 있다.

    // ThreadDump.txt

2020-09-30 17:44:26
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.201-b09 mixed mode):

"DestroyJavaVM" #13 prio=5 os_prio=31 tid=0x00007fb233800000 nid=0x1903 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Thread-2" #12 prio=5 os_prio=31 tid=0x00007fb2310bc800 nid=0x5803 runnable [0x0000700008a31000]
   java.lang.Thread.State: RUNNABLE
	at com.example.practice.threadDump.LoopingThread.run(MakeThreads.java:34)

"Thread-1" #11 prio=5 os_prio=31 tid=0x00007fb2310bb800 nid=0xa903 runnable [0x000070000892e000]
   java.lang.Thread.State: RUNNABLE
	at com.example.practice.threadDump.LoopingThread.run(MakeThreads.java:34)

"Thread-0" #10 prio=5 os_prio=31 tid=0x00007fb2310bb000 nid=0x5503 runnable [0x000070000882b000]
   java.lang.Thread.State: RUNNABLE
	at com.example.practice.threadDump.LoopingThread.run(MakeThreads.java:34)

"Service Thread" #9 daemon prio=9 os_prio=31 tid=0x00007fb231829000 nid=0x4303 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C1 CompilerThread3" #8 daemon prio=9 os_prio=31 tid=0x00007fb230805000 nid=0x4403 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread2" #7 daemon prio=9 os_prio=31 tid=0x00007fb231827800 nid=0x3d03 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" #6 daemon prio=9 os_prio=31 tid=0x00007fb232016800 nid=0x3b03 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #5 daemon prio=9 os_prio=31 tid=0x00007fb231048800 nid=0x3903 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 tid=0x00007fb231036800 nid=0x3703 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" #3 daemon prio=8 os_prio=31 tid=0x00007fb231825800 nid=0x4903 in Object.wait() [0x0000700008013000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0x00000006c000a470> (a java.lang.ref.ReferenceQueue$Lock)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
	- locked <0x00000006c000a470> (a java.lang.ref.ReferenceQueue$Lock)
	at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:165)
	at java.lang.ref.Finalizer$FinalizerThread.run(Finalizer.java:216)

"Reference Handler" #2 daemon prio=10 os_prio=31 tid=0x00007fb231824800 nid=0x4a03 in Object.wait() [0x0000700007f10000]
   java.lang.Thread.State: WAITING (on object monitor)
	at java.lang.Object.wait(Native Method)
	- waiting on <0x00000006c0004d00> (a java.lang.ref.Reference$Lock)
	at java.lang.Object.wait(Object.java:502)
	at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
	- locked <0x00000006c0004d00> (a java.lang.ref.Reference$Lock)
	at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

"VM Thread" os_prio=31 tid=0x00007fb231030000 nid=0x4c03 runnable 

"GC task thread#0 (ParallelGC)" os_prio=31 tid=0x00007fb231803800 nid=0x1f07 runnable 

"GC task thread#1 (ParallelGC)" os_prio=31 tid=0x00007fb231804000 nid=0x2a03 runnable 

"GC task thread#2 (ParallelGC)" os_prio=31 tid=0x00007fb231804800 nid=0x5403 runnable 

"GC task thread#3 (ParallelGC)" os_prio=31 tid=0x00007fb231805000 nid=0x2c03 runnable 

"GC task thread#4 (ParallelGC)" os_prio=31 tid=0x00007fb231806000 nid=0x5203 runnable 

"GC task thread#5 (ParallelGC)" os_prio=31 tid=0x00007fb231806800 nid=0x5003 runnable 

"GC task thread#6 (ParallelGC)" os_prio=31 tid=0x00007fb231807000 nid=0x4f03 runnable 

"GC task thread#7 (ParallelGC)" os_prio=31 tid=0x00007fb231807800 nid=0x4e03 runnable 

"VM Periodic Task Thread" os_prio=31 tid=0x00007fb23182a000 nid=0x4103 waiting on condition 

JNI global references: 5

Heap
 PSYoungGen      total 573440K, used 91534K [0x000000076ab00000, 0x00000007bc980000, 0x00000007c0000000)
  eden space 572928K, 15% used [0x000000076ab00000,0x000000077043bab8,0x000000078da80000)
  from space 512K, 31% used [0x00000007bc900000,0x00000007bc928000,0x00000007bc980000)
  to   space 512K, 0% used [0x00000007bc880000,0x00000007bc880000,0x00000007bc900000)
 ParOldGen       total 175104K, used 344K [0x00000006c0000000, 0x00000006cab00000, 0x000000076ab00000)
  object space 175104K, 0% used [0x00000006c0000000,0x00000006c0056050,0x00000006cab00000)
 Metaspace       used 2680K, capacity 4486K, committed 4864K, reserved 1056768K
  class space    used 288K, capacity 386K, committed 512K, reserved 1048576K

jstack을 사용하는 방법도 있다

kill 명령어를 사용하는 것이 불안하다면, 자바에서 기본적으로 제공하는 jstack이라는 명령어를 사용하는 방법도 있다. jstack 명령어를 수행하면 특정 프로세스의 단면을 생성하라고 강제로 지시하는 명령어다.

> lsof -i TCP:8080
COMMAND   PID        USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME
java    30011 incheoljung   62u  IPv6 0x399eb3c263471ea7      0t0  TCP *:http-alt (LISTEN)

> jstack 30011
2020-09-30 18:05:37
Full thread dump OpenJDK 64-Bit Server VM (13.0.2+8 mixed mode, sharing):

Threads class SMR info:
_java_thread_list=0x00007fb64eece5d0, length=35, elements={
0x00007fb64c813800, 0x00007fb64c804000, 0x00007fb64d0c7800, 0x00007fb64f808800,
0x00007fb64d803800, 0x00007fb64f81b000, 0x00007fb64e0ad800, 0x00007fb64f017000,
0x00007fb64f81c000, 0x00007fb650081000, 0x00007fb64f016000, 0x00007fb64f99c800,
0x00007fb64fa24000, 0x00007fb64fa25800, 0x00007fb6500b9800, 0x00007fb64c92d800,
0x00007fb650119800, 0x00007fb6500b5000, 0x00007fb64fa23000, 0x00007fb65011a000,
0x00007fb65011b000, 0x00007fb65011e800, 0x00007fb64d8b7000, 0x00007fb64d8c2800,
0x00007fb650845000, 0x00007fb64f9cc800, 0x00007fb64f9cd800, 0x00007fb64f9ce000,
0x00007fb64f9cf000, 0x00007fb64f9d0000, 0x00007fb64f9d1000, 0x00007fb650002800,
0x00007fb650057000, 0x00007fb65011c000, 0x00007fb64c816000
}

"Reference Handler" #2 daemon prio=10 os_prio=31 cpu=1.30ms elapsed=112.17s tid=0x00007fb64c813800 nid=0x4603 waiting on condition  [0x00007000025de000]
   java.lang.Thread.State: RUNNABLE
        at java.lang.ref.Reference.waitForReferencePendingList(java.base@13.0.2/Native Method)
        at java.lang.ref.Reference.processPendingReferences(java.base@13.0.2/Reference.java:241)
        at java.lang.ref.Reference$ReferenceHandler.run(java.base@13.0.2/Reference.java:213)

"Finalizer" #3 daemon prio=8 os_prio=31 cpu=0.25ms elapsed=112.17s tid=0x00007fb64c804000 nid=0x3d03 in Object.wait()  [0x00007000026e1000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(java.base@13.0.2/Native Method)
        - waiting on <0x00000007001bcc78> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(java.base@13.0.2/ReferenceQueue.java:155)
        - locked <0x00000007001bcc78> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(java.base@13.0.2/ReferenceQueue.java:176)
        at java.lang.ref.Finalizer$FinalizerThread.run(java.base@13.0.2/Finalizer.java:170)

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 cpu=0.24ms elapsed=112.16s tid=0x00007fb64d0c7800 nid=0x5603 runnable  [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C1 CompilerThread0" #5 daemon prio=9 os_prio=31 cpu=1383.76ms elapsed=112.16s tid=0x00007fb64f808800 nid=0x5803 waiting on condition  [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE
   No compile task

"Sweeper thread" #9 daemon prio=9 os_prio=31 cpu=16.41ms elapsed=112.16s tid=0x00007fb64d803800 nid=0xa603 runnable  [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Common-Cleaner" #10 daemon prio=8 os_prio=31 cpu=1.72ms elapsed=112.13s tid=0x00007fb64f81b000 nid=0xa403 in Object.wait()  [0x0000700002aed000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
        at java.lang.Object.wait(java.base@13.0.2/Native Method)
        - waiting on <0x00000007001c3bd8> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(java.base@13.0.2/ReferenceQueue.java:155)
        - locked <0x00000007001c3bd8> (a java.lang.ref.ReferenceQueue$Lock)
        at jdk.internal.ref.CleanerImpl.run(java.base@13.0.2/CleanerImpl.java:148)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)
        at jdk.internal.misc.InnocuousThread.run(java.base@13.0.2/InnocuousThread.java:134)

"Monitor Ctrl-Break" #11 daemon prio=5 os_prio=31 cpu=39.65ms elapsed=112.03s tid=0x00007fb64e0ad800 nid=0x5b03 runnable  [0x0000700002bf0000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.SocketDispatcher.read0(java.base@13.0.2/Native Method)
        at sun.nio.ch.SocketDispatcher.read(java.base@13.0.2/SocketDispatcher.java:47)
        at sun.nio.ch.NioSocketImpl.tryRead(java.base@13.0.2/NioSocketImpl.java:262)
        at sun.nio.ch.NioSocketImpl.implRead(java.base@13.0.2/NioSocketImpl.java:313)
        at sun.nio.ch.NioSocketImpl.read(java.base@13.0.2/NioSocketImpl.java:351)
        at sun.nio.ch.NioSocketImpl$1.read(java.base@13.0.2/NioSocketImpl.java:802)
        at java.net.Socket$SocketInputStream.read(java.base@13.0.2/Socket.java:937)
        at sun.nio.cs.StreamDecoder.readBytes(java.base@13.0.2/StreamDecoder.java:297)
        at sun.nio.cs.StreamDecoder.implRead(java.base@13.0.2/StreamDecoder.java:339)
        at sun.nio.cs.StreamDecoder.read(java.base@13.0.2/StreamDecoder.java:188)
        - locked <0x00000007001bc560> (a java.io.InputStreamReader)
        at java.io.InputStreamReader.read(java.base@13.0.2/InputStreamReader.java:185)
        at java.io.BufferedReader.fill(java.base@13.0.2/BufferedReader.java:161)
        at java.io.BufferedReader.readLine(java.base@13.0.2/BufferedReader.java:326)
        - locked <0x00000007001bc560> (a java.io.InputStreamReader)
        at java.io.BufferedReader.readLine(java.base@13.0.2/BufferedReader.java:392)
        at com.intellij.rt.execution.application.AppMainV2$1.run(AppMainV2.java:61)

"Service Thread" #12 daemon prio=9 os_prio=31 cpu=0.29ms elapsed=112.03s tid=0x00007fb64f017000 nid=0xa203 runnable  [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"RMI TCP Accept-0" #14 daemon prio=5 os_prio=31 cpu=9.52ms elapsed=111.57s tid=0x00007fb64f81c000 nid=0x6003 runnable  [0x0000700002df6000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.Net.accept(java.base@13.0.2/Native Method)
        at sun.nio.ch.NioSocketImpl.accept(java.base@13.0.2/NioSocketImpl.java:755)
        at java.net.ServerSocket.implAccept(java.base@13.0.2/ServerSocket.java:662)
        at java.net.ServerSocket.platformImplAccept(java.base@13.0.2/ServerSocket.java:628)
        at java.net.ServerSocket.implAccept(java.base@13.0.2/ServerSocket.java:604)
        at java.net.ServerSocket.implAccept(java.base@13.0.2/ServerSocket.java:561)
        at java.net.ServerSocket.accept(java.base@13.0.2/ServerSocket.java:518)
        at sun.management.jmxremote.LocalRMIServerSocketFactory$1.accept(jdk.management.agent@13.0.2/LocalRMIServerSocketFactory.java:52)
        at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.executeAcceptLoop(java.rmi@13.0.2/TCPTransport.java:394)
        at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.run(java.rmi@13.0.2/TCPTransport.java:366)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"logback-2" #19 daemon prio=5 os_prio=31 cpu=1.12ms elapsed=110.92s tid=0x00007fb650081000 nid=0x6407 waiting on condition  [0x0000700002ffc000]
   java.lang.Thread.State: TIMED_WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007005050a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.parkNanos(java.base@13.0.2/LockSupport.java:235)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(java.base@13.0.2/AbstractQueuedSynchronizer.java:2123)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1182)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"Attach Listener" #21 daemon prio=9 os_prio=31 cpu=10.55ms elapsed=110.60s tid=0x00007fb64f016000 nid=0x9a07 waiting on condition  [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"RMI Scheduler(0)" #24 daemon prio=5 os_prio=31 cpu=0.19ms elapsed=110.47s tid=0x00007fb64f99c800 nid=0x7603 waiting on condition  [0x0000700003c20000]
   java.lang.Thread.State: TIMED_WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007001113d0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.parkNanos(java.base@13.0.2/LockSupport.java:235)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(java.base@13.0.2/AbstractQueuedSynchronizer.java:2123)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1182)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"HikariPool-1 housekeeper" #28 daemon prio=5 os_prio=31 cpu=2.21ms elapsed=109.22s tid=0x00007fb64fa24000 nid=0x940f waiting on condition  [0x0000700003e26000]
   java.lang.Thread.State: TIMED_WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x000000070e292a68> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.parkNanos(java.base@13.0.2/LockSupport.java:235)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(java.base@13.0.2/AbstractQueuedSynchronizer.java:2123)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1182)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"Catalina-utility-1" #29 prio=1 os_prio=31 cpu=20.96ms elapsed=109.17s tid=0x00007fb64fa25800 nid=0x9003 waiting on condition  [0x0000700003f29000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x0000000701672220> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1177)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"Catalina-utility-2" #30 prio=1 os_prio=31 cpu=19.94ms elapsed=109.17s tid=0x00007fb6500b9800 nid=0x8e03 waiting on condition  [0x000070000402c000]
   java.lang.Thread.State: TIMED_WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x0000000701672220> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.parkNanos(java.base@13.0.2/LockSupport.java:235)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(java.base@13.0.2/AbstractQueuedSynchronizer.java:2123)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1182)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"container-0" #31 prio=5 os_prio=31 cpu=0.67ms elapsed=109.17s tid=0x00007fb64c92d800 nid=0x7b03 waiting on condition  [0x000070000412f000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
        at java.lang.Thread.sleep(java.base@13.0.2/Native Method)
        at org.apache.catalina.core.StandardServer.await(StandardServer.java:570)
        at org.springframework.boot.web.embedded.tomcat.TomcatWebServer$1.run(TomcatWebServer.java:197)

"File Watcher" #35 daemon prio=5 os_prio=31 cpu=577.12ms elapsed=108.77s tid=0x00007fb650119800 nid=0x8707 waiting on condition  [0x0000700004438000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
        at java.lang.Thread.sleep(java.base@13.0.2/Native Method)
        at org.springframework.boot.devtools.filewatch.FileSystemWatcher$Watcher.scan(FileSystemWatcher.java:250)
        at org.springframework.boot.devtools.filewatch.FileSystemWatcher$Watcher.run(FileSystemWatcher.java:234)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"Live Reload Server" #37 daemon prio=5 os_prio=31 cpu=0.19ms elapsed=108.76s tid=0x00007fb6500b5000 nid=0x8507 runnable  [0x000070000453b000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.Net.accept(java.base@13.0.2/Native Method)
        at sun.nio.ch.NioSocketImpl.accept(java.base@13.0.2/NioSocketImpl.java:755)
        at java.net.ServerSocket.implAccept(java.base@13.0.2/ServerSocket.java:662)
        at java.net.ServerSocket.platformImplAccept(java.base@13.0.2/ServerSocket.java:628)
        at java.net.ServerSocket.implAccept(java.base@13.0.2/ServerSocket.java:604)
        at java.net.ServerSocket.implAccept(java.base@13.0.2/ServerSocket.java:561)
        at java.net.ServerSocket.accept(java.base@13.0.2/ServerSocket.java:518)
        at org.springframework.boot.devtools.livereload.LiveReloadServer.acceptConnections(LiveReloadServer.java:145)
        at org.springframework.boot.devtools.livereload.LiveReloadServer$$Lambda$616/0x0000000800f23c40.run(Unknown Source)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-BlockPoller" #38 daemon prio=5 os_prio=31 cpu=11.30ms elapsed=108.72s tid=0x00007fb64fa23000 nid=0x8303 runnable  [0x000070000463e000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.KQueue.poll(java.base@13.0.2/Native Method)
        at sun.nio.ch.KQueueSelectorImpl.doSelect(java.base@13.0.2/KQueueSelectorImpl.java:122)
        at sun.nio.ch.SelectorImpl.lockAndDoSelect(java.base@13.0.2/SelectorImpl.java:124)
        - locked <0x0000000706487430> (a sun.nio.ch.Util$2)
        - locked <0x0000000706487258> (a sun.nio.ch.KQueueSelectorImpl)
        at sun.nio.ch.SelectorImpl.select(java.base@13.0.2/SelectorImpl.java:136)
        at org.apache.tomcat.util.net.NioBlockingSelector$BlockPoller.run(NioBlockingSelector.java:313)

"http-nio-8080-exec-1" #39 daemon prio=5 os_prio=31 cpu=0.17ms elapsed=108.72s tid=0x00007fb65011a000 nid=0xaa03 waiting on condition  [0x0000700004741000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-2" #40 daemon prio=5 os_prio=31 cpu=0.15ms elapsed=108.72s tid=0x00007fb65011b000 nid=0xac03 waiting on condition  [0x0000700004844000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-3" #41 daemon prio=5 os_prio=31 cpu=0.17ms elapsed=108.72s tid=0x00007fb65011e800 nid=0x15203 waiting on condition  [0x0000700004947000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-4" #42 daemon prio=5 os_prio=31 cpu=0.16ms elapsed=108.72s tid=0x00007fb64d8b7000 nid=0x14f03 waiting on condition  [0x0000700004a4a000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-5" #43 daemon prio=5 os_prio=31 cpu=0.17ms elapsed=108.72s tid=0x00007fb64d8c2800 nid=0xaf03 waiting on condition  [0x0000700004b4d000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-6" #44 daemon prio=5 os_prio=31 cpu=0.13ms elapsed=108.72s tid=0x00007fb650845000 nid=0x14c03 waiting on condition  [0x0000700004c50000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-7" #45 daemon prio=5 os_prio=31 cpu=0.11ms elapsed=108.72s tid=0x00007fb64f9cc800 nid=0x14903 waiting on condition  [0x0000700004d53000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-8" #46 daemon prio=5 os_prio=31 cpu=0.12ms elapsed=108.72s tid=0x00007fb64f9cd800 nid=0xb203 waiting on condition  [0x0000700004e56000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-9" #47 daemon prio=5 os_prio=31 cpu=0.14ms elapsed=108.72s tid=0x00007fb64f9ce000 nid=0x14603 waiting on condition  [0x0000700004f59000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-exec-10" #48 daemon prio=5 os_prio=31 cpu=0.14ms elapsed=108.72s tid=0x00007fb64f9cf000 nid=0xb503 waiting on condition  [0x000070000505c000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007064ce048> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.LinkedBlockingQueue.take(java.base@13.0.2/LinkedBlockingQueue.java:433)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:107)
        at org.apache.tomcat.util.threads.TaskQueue.take(TaskQueue.java:33)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at org.apache.tomcat.util.threads.TaskThread$WrappingRunnable.run(TaskThread.java:61)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-ClientPoller" #49 daemon prio=5 os_prio=31 cpu=12.09ms elapsed=108.72s tid=0x00007fb64f9d0000 nid=0xb603 runnable  [0x000070000515f000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.KQueue.poll(java.base@13.0.2/Native Method)
        at sun.nio.ch.KQueueSelectorImpl.doSelect(java.base@13.0.2/KQueueSelectorImpl.java:122)
        at sun.nio.ch.SelectorImpl.lockAndDoSelect(java.base@13.0.2/SelectorImpl.java:124)
        - locked <0x00000007064e7778> (a sun.nio.ch.Util$2)
        - locked <0x00000007064e7620> (a sun.nio.ch.KQueueSelectorImpl)
        at sun.nio.ch.SelectorImpl.select(java.base@13.0.2/SelectorImpl.java:136)
        at org.apache.tomcat.util.net.NioEndpoint$Poller.run(NioEndpoint.java:708)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"http-nio-8080-Acceptor" #50 daemon prio=5 os_prio=31 cpu=0.34ms elapsed=108.72s tid=0x00007fb64f9d1000 nid=0x14003 runnable  [0x0000700005262000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.Net.accept(java.base@13.0.2/Native Method)
        at sun.nio.ch.ServerSocketChannelImpl.accept(java.base@13.0.2/ServerSocketChannelImpl.java:276)
        at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:468)
        at org.apache.tomcat.util.net.NioEndpoint.serverSocketAccept(NioEndpoint.java:71)
        at org.apache.tomcat.util.net.Acceptor.run(Acceptor.java:95)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"DestroyJavaVM" #52 prio=5 os_prio=31 cpu=700.14ms elapsed=108.66s tid=0x00007fb650002800 nid=0x2203 waiting on condition  [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"logback-3" #58 daemon prio=5 os_prio=31 cpu=0.75ms elapsed=80.92s tid=0x00007fb650057000 nid=0x7d07 waiting on condition  [0x0000700003711000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007005050a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1177)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"logback-4" #59 daemon prio=5 os_prio=31 cpu=0.20ms elapsed=50.92s tid=0x00007fb65011c000 nid=0x6f0b waiting on condition  [0x0000700004232000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007005050a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1177)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"logback-5" #60 daemon prio=5 os_prio=31 cpu=0.23ms elapsed=20.93s tid=0x00007fb64c816000 nid=0x980b waiting on condition  [0x0000700003b1d000]
   java.lang.Thread.State: WAITING (parking)
        at jdk.internal.misc.Unsafe.park(java.base@13.0.2/Native Method)
        - parking to wait for  <0x00000007005050a0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(java.base@13.0.2/LockSupport.java:194)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(java.base@13.0.2/AbstractQueuedSynchronizer.java:2081)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:1177)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(java.base@13.0.2/ScheduledThreadPoolExecutor.java:899)
        at java.util.concurrent.ThreadPoolExecutor.getTask(java.base@13.0.2/ThreadPoolExecutor.java:1054)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(java.base@13.0.2/ThreadPoolExecutor.java:1114)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(java.base@13.0.2/ThreadPoolExecutor.java:628)
        at java.lang.Thread.run(java.base@13.0.2/Thread.java:830)

"VM Thread" os_prio=31 cpu=35.91ms elapsed=112.18s tid=0x00007fb64d0c6800 nid=0x3803 runnable  

"GC Thread#0" os_prio=31 cpu=32.18ms elapsed=112.19s tid=0x00007fb650036800 nid=0x5203 runnable  

"GC Thread#1" os_prio=31 cpu=27.48ms elapsed=111.20s tid=0x00007fb64d0eb800 nid=0x9f03 runnable  

"GC Thread#2" os_prio=31 cpu=30.13ms elapsed=111.20s tid=0x00007fb64d0de000 nid=0x6503 runnable  

"GC Thread#3" os_prio=31 cpu=34.69ms elapsed=111.20s tid=0x00007fb64d014800 nid=0x6703 runnable  

"GC Thread#4" os_prio=31 cpu=27.67ms elapsed=111.20s tid=0x00007fb64d1b0000 nid=0x6903 runnable  

"GC Thread#5" os_prio=31 cpu=31.77ms elapsed=111.20s tid=0x00007fb64d1b0800 nid=0x6a03 runnable  

"GC Thread#6" os_prio=31 cpu=24.80ms elapsed=110.91s tid=0x00007fb64f81f800 nid=0x7203 runnable  

"GC Thread#7" os_prio=31 cpu=14.32ms elapsed=110.91s tid=0x00007fb64f820000 nid=0x7403 runnable  

"G1 Main Marker" os_prio=31 cpu=0.29ms elapsed=112.19s tid=0x00007fb64f81a000 nid=0x5003 runnable  

"G1 Conc#0" os_prio=31 cpu=8.70ms elapsed=112.19s tid=0x00007fb64d009800 nid=0x4d03 runnable  

"G1 Conc#1" os_prio=31 cpu=8.51ms elapsed=109.95s tid=0x00007fb6500a8000 nid=0x9307 runnable  

"G1 Refine#0" os_prio=31 cpu=4.43ms elapsed=112.18s tid=0x00007fb64d0b7800 nid=0x3403 runnable  

"G1 Young RemSet Sampling" os_prio=31 cpu=35.89ms elapsed=112.18s tid=0x00007fb64d0b8000 nid=0x3503 runnable  
"VM Periodic Task Thread" os_prio=31 cpu=91.02ms elapsed=111.56s tid=0x00007fb64f023000 nid=0xa103 waiting on condition  

JNI global refs: 19, weak refs: 0

스레드 단면 해부하기

본격적으로 스레드 단면이 어떻게 되어 있는지 순서를 살펴보자

  1. 스레드 단면 생성 시간 정보

  2. JVM에 대한 정보

  3. 각 스레드의 스택을 포함한 다양한 정보

    • 스레드 이름

    • 식별자: 데몬 스레드일 경우에만 표시

    • 스레드 우선순위: 가장 낮은 것이 1, 높은 것이 10이다.

    • 스레드 ID(tid): 다른 스레드와 구분되는 스레드의 ID를 나타낸다. 정확하게 말하면, 해당 스레드가 점유하는 메모리의 주소를 표시한다.

    • 네이티브 스레드 ID(nid): OS에서 관리하는 스레드의 ID를 나타낸다.

    • 스레드의 상태: 스레드 단면을 생성할 때 해당 스레드가 하고 있던 작업에 대한 설명

    • 주소 범위: 스레드의 스택 영역의 예상된 주소 범위

  4. 데드록에 대한 정보

  5. 힙 영역의 사용 현황

참고

PreviousCHAP 08. 스레드 때문에(스레드에서) 발생하는 문제들NextCHAP 10. 잘라 놓은 스레드 단면 분석하기

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