Question

对于cassandra驱动程序4.0.0（com.datastax.oss / java-driver-core / 4.0.0），即使应用程序处于空闲状态，PreparedStatement（仅存在）也会使用一个CPU节点的100％：< / p>

import com.datastax.oss.driver.api.core.CqlSession;

import java.net.InetSocketAddress;

public class Demo_4_0_0 {
    public static void main(String[] args) throws Exception {
        CqlSession session = CqlSession.builder().addContactPoint(new InetSocketAddress("localhost", 9042)).withLocalDatacenter("datacenter1").build();
        System.out.println("before preparing select");
        Thread.sleep(15000);
        session.prepare("SELECT value FROM demo.demo WHERE partition = 0;");
        System.out.println("after preparing select");
        Thread.sleep(15000);
        session.close();
    }
}

与cassandra驱动程序3.7.1（com.datastax.cassandra / cassandra-driver-core / 3.7.1）相同的PreparedStatement表现良好-应用程序空闲时无CPU负载：

import com.datastax.driver.core.Cluster;
import com.datastax.driver.core.Session;

public class Demo_3_7_1 {
    public static void main(String[] args) throws Exception {
        Session session = Cluster.builder().addContactPoints("127.0.0.1").build().connect();
        System.out.println("before preparing select");
        Thread.sleep(15000);
        session.prepare("SELECT value FROM demo.demo WHERE partition = 0;");
        System.out.println("after preparing select");
        Thread.sleep(15000);
        session.close();
    }
}

为使示例起作用，请在cassandra中首先执行：

CREATE KEYSPACE demo WITH REPLICATION = {'class':'SimpleStrategy', 'replication_factor':1};
CREATE TABLE demo.demo (partition INT PRIMARY KEY, value INT);

我的环境：Cassandra 3.11.2（作为docker容器），jdk1.8.0_111 x64，Windows 10、8个CPU。

有什么想法吗？

其他信息：在准备该语句之前和之后的线程转储看起来都一样，唯一的例外是出现了“ s0-timer-0”线程：

"s0-timer-0" #12 prio=5 os_prio=0 tid=0x0000000021392000 nid=0xcd0 runnable [0x0000000024f1e000]
   java.lang.Thread.State: RUNNABLE
        at java.lang.Thread.sleep(Native Method)
        at io.netty.util.HashedWheelTimer$Worker.waitForNextTick(HashedWheelTimer.java:579)
        at io.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:478)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

这是准备语句后的完整线程转储：

2019-04-06 10:50:54
Full thread dump Java HotSpot(TM) 64-Bit Server VM (25.202-b08 mixed mode):

"s0-timer-0" #12 prio=5 os_prio=0 tid=0x0000000021392000 nid=0xcd0 runnable [0x0000000024f1e000]
   java.lang.Thread.State: RUNNABLE
        at java.lang.Thread.sleep(Native Method)
        at io.netty.util.HashedWheelTimer$Worker.waitForNextTick(HashedWheelTimer.java:579)
        at io.netty.util.HashedWheelTimer$Worker.run(HashedWheelTimer.java:478)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"JMX server connection timeout 20" #20 daemon prio=5 os_prio=0 tid=0x000000001ff32000 nid=0xb90 in Object.wait() [0x0000000024a1f000]
   java.lang.Thread.State: TIMED_WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x000000076b779218> (a [I)
        at com.sun.jmx.remote.internal.ServerCommunicatorAdmin$Timeout.run(Unknown Source)
        - locked <0x000000076b779218> (a [I)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"RMI Scheduler(0)" #19 daemon prio=5 os_prio=0 tid=0x000000001ff31000 nid=0x13ac waiting on condition [0x000000002491f000]
   java.lang.Thread.State: TIMED_WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x000000076f8c4ca0> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(Unknown Source)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(Unknown Source)
        at java.util.concurrent.ScheduledThreadPoolExecutor$DelayedWorkQueue.take(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.getTask(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"RMI TCP Connection(1)-10.0.75.1" #18 daemon prio=5 os_prio=0 tid=0x0000000020be7800 nid=0x27b0 runnable [0x000000002481d000]
   java.lang.Thread.State: RUNNABLE
        at java.net.SocketInputStream.socketRead0(Native Method)
        at java.net.SocketInputStream.socketRead(Unknown Source)
        at java.net.SocketInputStream.read(Unknown Source)
        at java.net.SocketInputStream.read(Unknown Source)
        at java.io.BufferedInputStream.fill(Unknown Source)
        at java.io.BufferedInputStream.read(Unknown Source)
        - locked <0x000000076b73dae0> (a java.io.BufferedInputStream)
        at java.io.FilterInputStream.read(Unknown Source)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(Unknown Source)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(Unknown Source)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(Unknown Source)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler$$Lambda$180/1667804988.run(Unknown Source)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - <0x000000076b553ee8> (a java.util.concurrent.ThreadPoolExecutor$Worker)

"RMI TCP Accept-0" #17 daemon prio=5 os_prio=0 tid=0x0000000020b3c000 nid=0x448c runnable [0x000000002461f000]
   java.lang.Thread.State: RUNNABLE
        at java.net.DualStackPlainSocketImpl.accept0(Native Method)
        at java.net.DualStackPlainSocketImpl.socketAccept(Unknown Source)
        at java.net.AbstractPlainSocketImpl.accept(Unknown Source)
        at java.net.PlainSocketImpl.accept(Unknown Source)
        - locked <0x000000076f400858> (a java.net.SocksSocketImpl)
        at java.net.ServerSocket.implAccept(Unknown Source)
        at java.net.ServerSocket.accept(Unknown Source)
        at sun.management.jmxremote.LocalRMIServerSocketFactory$1.accept(Unknown Source)
        at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.executeAcceptLoop(Unknown Source)
        at sun.rmi.transport.tcp.TCPTransport$AcceptLoop.run(Unknown Source)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"s0-io-1" #16 prio=5 os_prio=0 tid=0x0000000020b34000 nid=0x33f8 runnable [0x000000002310f000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
        at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(Unknown Source)
        at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(Unknown Source)
        at sun.nio.ch.WindowsSelectorImpl.doSelect(Unknown Source)
        at sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
        - locked <0x000000076f413268> (a io.netty.channel.nio.SelectedSelectionKeySet)
        - locked <0x000000076f413280> (a java.util.Collections$UnmodifiableSet)
        - locked <0x000000076f4131e8> (a sun.nio.ch.WindowsSelectorImpl)
        at sun.nio.ch.SelectorImpl.select(Unknown Source)
        at io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:62)
        at io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:786)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:434)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:905)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"s0-io-0" #15 prio=5 os_prio=0 tid=0x00000000203cd800 nid=0x368c runnable [0x0000000021aff000]
   java.lang.Thread.State: RUNNABLE
        at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll0(Native Method)
        at sun.nio.ch.WindowsSelectorImpl$SubSelector.poll(Unknown Source)
        at sun.nio.ch.WindowsSelectorImpl$SubSelector.access$400(Unknown Source)
        at sun.nio.ch.WindowsSelectorImpl.doSelect(Unknown Source)
        at sun.nio.ch.SelectorImpl.lockAndDoSelect(Unknown Source)
        - locked <0x000000076f40b900> (a io.netty.channel.nio.SelectedSelectionKeySet)
        - locked <0x000000076f40b918> (a java.util.Collections$UnmodifiableSet)
        - locked <0x000000076f40b880> (a sun.nio.ch.WindowsSelectorImpl)
        at sun.nio.ch.SelectorImpl.select(Unknown Source)
        at io.netty.channel.nio.SelectedSelectionKeySetSelector.select(SelectedSelectionKeySetSelector.java:62)
        at io.netty.channel.nio.NioEventLoop.select(NioEventLoop.java:786)
        at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:434)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:905)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"s0-admin-1" #14 prio=5 os_prio=0 tid=0x00000000202c7000 nid=0x4aac waiting on condition [0x0000000020a2f000]
   java.lang.Thread.State: TIMED_WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x000000076f418190> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.parkNanos(Unknown Source)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.awaitNanos(Unknown Source)
        at java.util.concurrent.LinkedBlockingQueue.poll(Unknown Source)
        at io.netty.util.concurrent.SingleThreadEventExecutor.takeTask(SingleThreadEventExecutor.java:251)
        at io.netty.channel.DefaultEventLoop.run(DefaultEventLoop.java:52)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:905)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"s0-admin-0" #13 prio=5 os_prio=0 tid=0x00000000202b5800 nid=0x4158 waiting on condition [0x000000002072e000]
   java.lang.Thread.State: WAITING (parking)
        at sun.misc.Unsafe.park(Native Method)
        - parking to wait for  <0x000000076f420180> (a java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject)
        at java.util.concurrent.locks.LockSupport.park(Unknown Source)
        at java.util.concurrent.locks.AbstractQueuedSynchronizer$ConditionObject.await(Unknown Source)
        at java.util.concurrent.LinkedBlockingQueue.take(Unknown Source)
        at io.netty.util.concurrent.SingleThreadEventExecutor.takeTask(SingleThreadEventExecutor.java:238)
        at io.netty.channel.DefaultEventLoop.run(DefaultEventLoop.java:52)
        at io.netty.util.concurrent.SingleThreadEventExecutor$5.run(SingleThreadEventExecutor.java:905)
        at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
        at java.lang.Thread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"Service Thread" #10 daemon prio=9 os_prio=0 tid=0x000000001eb95000 nid=0x2b30 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
        - None

"C1 CompilerThread3" #9 daemon prio=9 os_prio=2 tid=0x000000001eb11800 nid=0x1948 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
        - None

"C2 CompilerThread2" #8 daemon prio=9 os_prio=2 tid=0x000000001eb05800 nid=0x56c waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
        - None

"C2 CompilerThread1" #7 daemon prio=9 os_prio=2 tid=0x000000001eafd800 nid=0x4a04 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
        - None

"C2 CompilerThread0" #6 daemon prio=9 os_prio=2 tid=0x000000001eafa800 nid=0x1e0c waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
        - None

"Attach Listener" #5 daemon prio=5 os_prio=2 tid=0x000000001eaf8800 nid=0x34c4 waiting on condition [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
        - None

"Signal Dispatcher" #4 daemon prio=9 os_prio=2 tid=0x000000001cc1e000 nid=0x36f0 runnable [0x0000000000000000]
   java.lang.Thread.State: RUNNABLE

   Locked ownable synchronizers:
        - None

"Finalizer" #3 daemon prio=8 os_prio=1 tid=0x000000000319e800 nid=0x4acc in Object.wait() [0x000000001efce000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x000000076f438180> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(Unknown Source)
        - locked <0x000000076f438180> (a java.lang.ref.ReferenceQueue$Lock)
        at java.lang.ref.ReferenceQueue.remove(Unknown Source)
        at java.lang.ref.Finalizer$FinalizerThread.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"Reference Handler" #2 daemon prio=10 os_prio=2 tid=0x0000000003195000 nid=0x4118 in Object.wait() [0x000000001eace000]
   java.lang.Thread.State: WAITING (on object monitor)
        at java.lang.Object.wait(Native Method)
        - waiting on <0x000000076f430468> (a java.lang.ref.Reference$Lock)
        at java.lang.Object.wait(Unknown Source)
        at java.lang.ref.Reference.tryHandlePending(Unknown Source)
        - locked <0x000000076f430468> (a java.lang.ref.Reference$Lock)
        at java.lang.ref.Reference$ReferenceHandler.run(Unknown Source)

   Locked ownable synchronizers:
        - None

"main" #1 prio=5 os_prio=0 tid=0x00000000011be000 nid=0x3c90 waiting on condition [0x000000000301f000]
   java.lang.Thread.State: TIMED_WAITING (sleeping)
        at java.lang.Thread.sleep(Native Method)
        at bug.Demo_4_0_0.main(Demo_4_0_0.java:14)

   Locked ownable synchronizers:
        - None

"VM Thread" os_prio=2 tid=0x000000001cc0a000 nid=0x17c8 runnable 

"GC task thread#0 (ParallelGC)" os_prio=0 tid=0x00000000030b7800 nid=0x4b9c runnable 

"GC task thread#1 (ParallelGC)" os_prio=0 tid=0x00000000030b9800 nid=0x9c8 runnable 

"GC task thread#2 (ParallelGC)" os_prio=0 tid=0x00000000030bb000 nid=0x46e8 runnable 

"GC task thread#3 (ParallelGC)" os_prio=0 tid=0x00000000030bd000 nid=0x3234 runnable 

"GC task thread#4 (ParallelGC)" os_prio=0 tid=0x00000000030be800 nid=0x3160 runnable 

"GC task thread#5 (ParallelGC)" os_prio=0 tid=0x00000000030bf800 nid=0xc20 runnable 

"GC task thread#6 (ParallelGC)" os_prio=0 tid=0x00000000030c3800 nid=0x4298 runnable 

"GC task thread#7 (ParallelGC)" os_prio=0 tid=0x00000000030c5000 nid=0x429c runnable 

"VM Periodic Task Thread" os_prio=2 tid=0x000000001ebaf000 nid=0x4a20 waiting on condition 

JNI global references: 664

Answer 1

我今天对此进行了调查，因为我们已经有一些关于此事的报道（JAVA-2264）。

这似乎是由于以下事实引起的：netty的HashedWheelTimer计时器代码中有一些特殊的逻辑将睡眠时间延长到10倍：

// Check if we run on windows, as if thats the case we will need
// to round the sleepTime as workaround for a bug that only affect
// the JVM if it runs on windows.
//
// See https://github.com/netty/netty/issues/356
if (PlatformDependent.isWindows()) {
    sleepTimeMs = sleepTimeMs / 10 * 10;
}

通常这没关系，但是默认情况下，java驱动程序将HashedWheelTimer的滴答持续时间配置为1ms。由于sleepTimeMs很长，我猜想我们正在像1/10*10 = 0那样紧张地睡觉。

我们将在驱动程序中找到解决方案，无论是整体上调整默认的滴答时间（也许1ms太激进），还是仅针对Windows。

在此之前，您可以通过以下两种方法之一解决此问题：

将系统属性-Ddatastax-java-driver.advanced.netty.timer.tick-duration="100 millseconds"传递给您的应用程序
在application.conf中设置datastax-java-driver.advanced.netty.timer.tick-duration=100 millseconds

cassandra 4.0.0驱动程序-PreparedStatement使用一个CPU节点的100％？

1 个答案: