错误获取锁(org.neo4j.kernal.StoreLockException)

Question

当试图在现有数据库中创建新节点时，我将得到以下异常：

org.neo4j.kernal.StoreLockException。

下面的代码片段是导致异常的实际行。下面，我附加了一些更多的细节和完整的堆栈跟踪。

如果我创建了一个新文件夹并将其用作DB_PATH，那么我的代码在第一次运行时运行良好。在第二次运行中，它将在相同的例外情况下失败。似乎有什么东西阻止了锁的获取。

我试图设置对DB_PATH中的每个文件进行读写的权限。不走运。其中一个配置文件中是否有关于锁必须禁用的设置？

代码抛出异常

graphDB = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );

详细信息(第6行)

private static GraphDatabaseService graphDB = null;
public static final String DB_PATH = "/Users/NtroduceMe/Downloads/neo4j-community-2.0.0-M03/data/ntroduceme";
private static Index<Node> userNodeIndex;
private static Index<Node> rememberMeNodeIndex;
static {
    graphDB = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
    registerShutdownHook(graphDB);
    userNodeIndex = graphDB.index().forNodes("profile_id");
    rememberMeNodeIndex = graphDB.index().forNodes("profile_id");
}

堆栈跟踪

Jun 19, 2013 12:12:50 AM org.apache.catalina.core.StandardWrapperValve invoke
SEVERE: Servlet.service() for servlet [ProfileController] in context with path [] threw exception [Servlet execution threw an exception] with root cause
org.neo4j.kernel.StoreLockException: Could not create lock file
    at org.neo4j.kernel.StoreLocker.checkLock(StoreLocker.java:85)
    at org.neo4j.kernel.StoreLockerLifecycleAdapter.start(StoreLockerLifecycleAdapter.java:40)
    at org.neo4j.kernel.lifecycle.LifeSupport$LifecycleInstance.start(LifeSupport.java:498)
    at org.neo4j.kernel.lifecycle.LifeSupport.start(LifeSupport.java:115)
    at org.neo4j.kernel.InternalAbstractGraphDatabase.run(InternalAbstractGraphDatabase.java:296)
    at org.neo4j.kernel.EmbeddedGraphDatabase.<init>(EmbeddedGraphDatabase.java:100)
    at org.neo4j.graphdb.factory.GraphDatabaseFactory$1.newDatabase(GraphDatabaseFactory.java:92)
    at org.neo4j.graphdb.factory.GraphDatabaseBuilder.newGraphDatabase(GraphDatabaseBuilder.java:197)
    at org.neo4j.graphdb.factory.GraphDatabaseFactory.newEmbeddedDatabase(GraphDatabaseFactory.java:69)
    at com.NtroduceMe.Utilities.GraphDBManager.<clinit>(GraphDBManager.java:22)
    at com.NtroduceMe.UserProfile.Profiles.createProfile(Profiles.java:141)
    at com.NtroduceMe.UserProfile.ProfileController.doPost(ProfileController.java:61)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:647)
    at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.netbeans.modules.web.monitor.server.MonitorFilter.doFilter(MonitorFilter.java:393)
    at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
    at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
    at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
    at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
    at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
    at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
    at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:99)
    at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:936)
    at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
    at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
    at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1004)
    at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:589)
    at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:312)
    at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
    at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
    at java.lang.Thread.run(Thread.java:722)

用于存储数据库实例的帮助类

public class GraphDBManager {
    public static final String DB_PATH = "/Users/NtroduceMe/Downloads/neo4j-community-2.0.0-M03/data/ntroduceme";
    private static final GraphDatabaseService graphDB = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );    
    private static Index<Node> userNodeIndex;
    private static Index<Node> rememberMeNodeIndex;
    static {
        registerShutdownHook(graphDB);
        userNodeIndex = graphDB.index().forNodes("profile_id");
        rememberMeNodeIndex = graphDB.index().forNodes("profile_id");
    }

    public static GraphDatabaseService getGraphDB(){
        return graphDB;
    }

    public static Index<Node> getUserNodeIndex(){
        return userNodeIndex;
    }

    public static Index<Node> getRemberMeNodeIndex(){
        return rememberMeNodeIndex;
    }

    private static void registerShutdownHook(final GraphDatabaseService graphDb )
    {
        // Registers a shutdown hook for the Neo4j instance so that it
        // shuts down nicely when the VM exits (even if you "Ctrl-C" the
        // running application).
        Runtime.getRuntime().addShutdownHook( new Thread()
        {
            @Override
            public void run()
            {
                graphDb.shutdown();
            }
        } );
    }   

}

Answer 1

当程序结束时，您没有正确地关闭数据库，所以它将锁文件留在那里。

您可以考虑设置一个关闭钩子，如下所述：http://docs.neo4j.org/chunked/stable/tutorials-java-embedded-setup.html#tutorials-java-embedded-setup-startstop

Answer 2

我只是想知道为什么在创建节点之前关闭DB？

不能使用关闭的DB创建节点，所以可以这样：

 graphDB = new GraphDatabaseFactory().newEmbeddedDatabase( DB_PATH );
 userNodeIndex = graphDB.index().forNodes("profile_id");
 rememberMeNodeIndex = graphDB.index().forNodes("profile_id");
 Transaction tx = graphDb.beginTx();
 try
    {
    Node node = graphDb.createNode();
    node.setProperty( USER_ID, "userID");
    nodeIndex.add( node, USER_ID, "userID" );
    }

在fininsh创建所有节点之后，您可以调用：

   registerShutdownHook(graphDB);

Answer 3

我不知道发生了什么，但您可以简单地检查一下您的graphdb目录中是否有"store_lock“文件，如果没有，只需创建它(使用”触摸“命令)或其他什么？这应该能解决问题。