使用 Reactive Mongo 驱动程序时 Scala 控制台应用程序不退出

Question

我正在使用 ReactiveMongo 0.16.1 和 MongoDB 4.0。

主要 class 我运行以下内容：

  DataManager.processFeedbacks
  val future1 = DataManager.processNewEvaluations
  val future2 = DataManager.processPurchases
  val future3 = DataManager.processExpiredEvaluations
  val future4 = DataManager.processExpiredCommerialLicenses
  val futures = List(future1, future2, future3, future4).map(_.map(Try(_)))
  val complete = Future.sequence(futures).onComplete _
  complete(_ => {
    DatabaseConfigService.closeDriver
  })

一切正常，除了我无法关闭驱动程序并且主线程继续挂起，不允许应用程序退出。

在 closeDriver() 中，我尝试了 driver.close、conn.askClose()(Duration.create(10, TimeUnit.SECONDS) 和

futureConnection.map(conn => {
     conn.askClose()(Duration.create(10, TimeUnit.SECONDS))
       .onComplete(y => driver.close())
   })

如您所料，一切都没有结果。

这是转储线程：

2019-02-05 14:33:18
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.191-b12 mixed mode):

"Analytics" #68 prio=1 os_prio=31 tid=0x00007fc9fd92c800 nid=0x9f07 waiting on condition [0x000070000dc97000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x000000076b960148> (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 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 com.segment.analytics.Platform.run(Platform.java:45)
    at java.lang.Thread.run(Thread.java:748)

"DestroyJavaVM" #40 prio=5 os_prio=31 tid=0x00007fc9fc0ff000 nid=0x1903 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Analytics" #32 prio=1 os_prio=31 tid=0x00007fc9fe0b4800 nid=0x6203 waiting on condition [0x000070000eecd000]
   java.lang.Thread.State: TIMED_WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x000000076ba51808> (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.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:1093)
    at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(ScheduledThreadPoolExecutor.java:809)
    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 com.segment.analytics.Platform.run(Platform.java:45)
    at java.lang.Thread.run(Thread.java:748)

"Analytics" #31 prio=1 os_prio=31 tid=0x00007fc9fe0b2800 nid=0x6103 waiting on condition [0x000070000edca000]
   java.lang.Thread.State: WAITING (parking)
    at sun.misc.Unsafe.park(Native Method)
    - parking to wait for  <0x000000076ba3a870> (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 com.segment.analytics.internal.AnalyticsClient$Looper.run(AnalyticsClient.java:106)
    at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
    at java.util.concurrent.FutureTask.run(FutureTask.java:266)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
    at com.segment.analytics.Platform.run(Platform.java:45)
    at java.lang.Thread.run(Thread.java:748)

"Service Thread" #10 daemon prio=9 os_prio=31 tid=0x00007fc9fe0dd000 nid=0x3e03 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C1 CompilerThread3" #9 daemon prio=9 os_prio=31 tid=0x00007fc9ff00b800 nid=0x4003 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread2" #8 daemon prio=9 os_prio=31 tid=0x00007fc9fc801000 nid=0x3c03 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread1" #7 daemon prio=9 os_prio=31 tid=0x00007fc9fc1b1800 nid=0x3b03 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"C2 CompilerThread0" #6 daemon prio=9 os_prio=31 tid=0x00007fc9fe0dc800 nid=0x3903 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Monitor Ctrl-Break" #5 daemon prio=5 os_prio=31 tid=0x00007fc9fe0db000 nid=0x3703 runnable [0x000070000d582000]
   java.lang.Thread.State: RUNNABLE
    at java.net.SocketInputStream.socketRead0(Native Method)
    at java.net.SocketInputStream.socketRead(SocketInputStream.java:116)
    at java.net.SocketInputStream.read(SocketInputStream.java:171)
    at java.net.SocketInputStream.read(SocketInputStream.java:141)
    at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:284)
    at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:326)
    at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:178)
    - locked <0x00000006c0015800> (a java.io.InputStreamReader)
    at java.io.InputStreamReader.read(InputStreamReader.java:184)
    at java.io.BufferedReader.fill(BufferedReader.java:161)
    at java.io.BufferedReader.readLine(BufferedReader.java:324)
    - locked <0x00000006c0015800> (a java.io.InputStreamReader)
    at java.io.BufferedReader.readLine(BufferedReader.java:389)
    at com.intellij.rt.execution.application.AppMainV2.run(AppMainV2.java:64)

"Signal Dispatcher" #4 daemon prio=9 os_prio=31 tid=0x00007fc9fb85d000 nid=0x4303 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

"Finalizer" #3 daemon prio=8 os_prio=31 tid=0x00007fc9fd800000 nid=0x4703 in Object.wait() [0x000070000d37c000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000006c00170e0> (a java.lang.ref.ReferenceQueue$Lock)
    at java.lang.ref.ReferenceQueue.remove(ReferenceQueue.java:144)
    - locked <0x00000006c00170e0> (a java.lang.ref.ReferenceQueue$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=0x00007fc9fb83f800 nid=0x4903 in Object.wait() [0x000070000d279000]
   java.lang.Thread.State: WAITING (on object monitor)
    at java.lang.Object.wait(Native Method)
    - waiting on <0x00000006c001e220> (a java.lang.ref.Reference$Lock)
    at java.lang.Object.wait(Object.java:502)
    at java.lang.ref.Reference.tryHandlePending(Reference.java:191)
    - locked <0x00000006c001e220> (a java.lang.ref.Reference$Lock)
    at java.lang.ref.Reference$ReferenceHandler.run(Reference.java:153)

"VM Thread" os_prio=31 tid=0x00007fc9fb839000 nid=0x4b03 runnable 

"GC task thread#0 (ParallelGC)" os_prio=31 tid=0x00007fc9fe801800 nid=0x2507 runnable 

"GC task thread#1 (ParallelGC)" os_prio=31 tid=0x00007fc9fe802800 nid=0x2a03 runnable 

"GC task thread#2 (ParallelGC)" os_prio=31 tid=0x00007fc9fe803000 nid=0x2b03 runnable 

"GC task thread#3 (ParallelGC)" os_prio=31 tid=0x00007fc9ff000000 nid=0x5203 runnable 

"GC task thread#4 (ParallelGC)" os_prio=31 tid=0x00007fc9ff001000 nid=0x5003 runnable 

"GC task thread#5 (ParallelGC)" os_prio=31 tid=0x00007fc9ff800000 nid=0x4f03 runnable 

"GC task thread#6 (ParallelGC)" os_prio=31 tid=0x00007fc9fe00a000 nid=0x2d03 runnable 

"GC task thread#7 (ParallelGC)" os_prio=31 tid=0x00007fc9ff801000 nid=0x2e03 runnable 

"VM Periodic Task Thread" os_prio=31 tid=0x00007fc9fe800000 nid=0x5503 waiting on condition 

JNI global references: 2012

Heap
 PSYoungGen      total 116736K, used 58485K [0x000000076ab00000, 0x0000000772a80000, 0x00000007c0000000)
  eden space 105984K, 55% used [0x000000076ab00000,0x000000076e41d548,0x0000000771280000)
  from space 10752K, 0% used [0x0000000771d00000,0x0000000771d00000,0x0000000772780000)
  to   space 10752K, 0% used [0x0000000771280000,0x0000000771280000,0x0000000771d00000)
 ParOldGen       total 141312K, used 10517K [0x00000006c0000000, 0x00000006c8a00000, 0x000000076ab00000)
  object space 141312K, 7% used [0x00000006c0000000,0x00000006c0a45578,0x00000006c8a00000)
 Metaspace       used 38906K, capacity 42786K, committed 42968K, reserved 1087488K
  class space    used 5527K, capacity 5819K, committed 5888K, reserved 1048576K

P.S。看来我有。但是，那个post是2015年的，早就应该部署修复了。。。不过，我还是无法关闭驱动。

Answer 1

经常发生，问题出在电脑和椅子之间...我post在这里回答，希望有一天它能对某人有所帮助。

我错过了代码中的第一行 DataManager.processFeedbacks 也创建了一个未来。我没有等待它完成，而是过早地关闭了驱动程序。

我通过再次检查转储线程并查找我的代码正在使用的类来解决这个问题。类之一被 processFeedbacks() 函数

使用

使用 Reactive Mongo 驱动程序时 Scala 控制台应用程序不退出

Scala Console App Does Not Exit When Using Reactive Mongo Driver

concurrency

scala

mongodb

reactivemongo