10

这是我的 Main.java 源代码。它是从 neo4j-apoc-1.0 示例中获取的。修改存储2个节点1个关系1M条记录的目标:

package javaapplication2;

import org.neo4j.graphdb.GraphDatabaseService;
import org.neo4j.graphdb.Node;
import org.neo4j.graphdb.RelationshipType;
import org.neo4j.graphdb.Transaction;
import org.neo4j.kernel.EmbeddedGraphDatabase;


public class Main
{
    private static final String DB_PATH = "neo4j-store-1M";
    private static final String NAME_KEY = "name";

    private static enum ExampleRelationshipTypes implements RelationshipType
    {
        EXAMPLE
    }

    public static void main(String[] args)
    {
        GraphDatabaseService graphDb = null;

        try
        {
            System.out.println( "Init database..." );


            graphDb = new EmbeddedGraphDatabase( DB_PATH );

            registerShutdownHook( graphDb );


            System.out.println( "Start of creating database..." );


            int valIndex = 0;

            for(int i=0; i<1000; ++i)
            {
                for(int j=0; j<1000; ++j)
                {
                    Transaction tx = graphDb.beginTx();

                    try
                    {
                        Node firstNode = graphDb.createNode();
            firstNode.setProperty( NAME_KEY, "Hello" + valIndex );

                        Node secondNode = graphDb.createNode();
            secondNode.setProperty( NAME_KEY, "World" + valIndex );

                        firstNode.createRelationshipTo(
                           secondNode, ExampleRelationshipTypes.EXAMPLE );

                        tx.success();

                        ++valIndex;
                    }
                    finally
                    {
                        tx.finish();
                    }
                }
            }

            System.out.println("Ok, client processing finished!");
        }
        finally
        {
            System.out.println( "Shutting down database ..." );

            graphDb.shutdown();
        }
    }

    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 example before it's completed)
        Runtime.getRuntime().addShutdownHook( new Thread()
        {
            @Override
            public void run()
            {
                graphDb.shutdown();
            }
        } );
    }
}

经过几次迭代(大约 150K)后,我收到了错误消息:

“java.lang.OutOfMemoryError:在 org.neo4j.kernel.impl.nioneo 的 java.nio.ByteBuffer.allocate(ByteBuffer.java:312) 处的 java.nio.HeapByteBuffer.(HeapByteBuffer.java:39) 处的 Java 堆空间。 store.PlainPersistenceWindow.(PlainPersistenceWindow.java:30) at org.neo4j.kernel.impl.nioneo.store.PersistenceWindowPool.allocateNewWindow(PersistenceWindowPool.java:534) at org.neo4j.kernel.impl.nioneo.store.PersistenceWindowPool.refreshBricks (PersistenceWindowPool.java:430) 在 org.neo4j.kernel.impl.nioneo.store.PersistenceWindowPool.acquire(PersistenceWindowPool.java:122) 在 org.neo4j.kernel.impl.nioneo.store.CommonAbstractStore.acquireWindow(CommonAbstractStore.java :459) 在 org.neo4j 的 org.neo4j.kernel.impl.nioneo.store.AbstractDynamicStore.updateRecord(AbstractDynamicStore.java:240)。kernel.impl.nioneo.store.PropertyStore.updateRecord(PropertyStore.java:209) 在 org.neo4j.kernel.impl.nioneo.xa.Command$PropertyCommand.execute(Command.java:513) 在 org.neo4j.kernel。 impl.nioneo.xa.NeoTransaction.doCommit(NeoTransaction.java:443) 在 org.neo4j.kernel.impl.transaction.xaframework.XaTransaction.commit(XaTransaction.java:316) 在 org.neo4j.kernel.impl.transaction。 xaframework.XaResourceManager.commit(XaResourceManager.java:399) at org.neo4j.kernel.impl.transaction.xaframework.XaResourceHelpImpl.commit(XaResourceHelpImpl.java:64) at org.neo4j.kernel.impl.transaction.TransactionImpl.doCommit( TransactionImpl.java:514) 在 org.neo4j.kernel.impl.transaction.TxManager.commit(TxManager.java:571) 在 org.neo4j.kernel.impl.transaction.TxManager.commit(TxManager.java:543) 在 org .neo4j.kernel.impl.transaction.TransactionImpl.commit(TransactionImpl.java:102) at org.neo4j.kernel.EmbeddedGraphDbImpl$TransactionImpl.finish(EmbeddedGraphDbImpl.java:329) at javaapplication2.Main.main(Main.java:62) 28.05.2010 9:52:14 org.neo4j.kernel.impl.nioneo.store.PersistenceWindowPool logWarn 警告:[neo4j-store-1M\neostore.propertystore.db.strings] 无法分配直接缓冲区”

伙计们!帮助我plzzz,我做错了什么,我该如何修复它?在平台 Windows XP 32bit SP3 上测试。也许创建自定义配置中的解决方案?

thnx 4 每个建议!

4

1 回答 1

6

这是 Windows 上的配置问题,其中 Neo4j 无法使用内存映射缓冲区。而是在堆上创建一个 Java 缓冲区。在 1.0 中,这个缓冲区的默认大小是 470MB,这比 Windows JVM 的默认堆要大。你有两个选择:

  1. 切换到具有自动配置的 pom.xml 中的 APOC 1.1-SNAPSHOT 而不是 1.0,将最多 50% 的可用 JVM 堆分配给 Neo4j

  2. 通过运行 Java 将 JVM 堆调整为更多(例如 512Mb)

    java -Xmx512m ....

    您甚至可以在 Eclipse 中的运行配置中的 JVM 参数下插入它

让我们知道这是否有帮助!

此外,为每个节点对执行完整的事务将需要很长时间。尝试在第一个循环中打开一个事务并仅每 1000 个节点对提交一次?

/彼得

于 2010-05-28T09:49:51.387 回答