我正在从 AWS 推广 DynamoDB + JanusGraph 教程，这样，给定具有标准约定的标准 .txt 文件，程序可以摄取数据（作为三元组）并创建顶点、属性和边。通常我不会发布这么长的问题，但似乎这些都与我创建的同一个类 ObjectCreationCommand 中的 4-5 行有关。
Triple 的示例如下所示："name:Jim Henson \t isCreatorOf \t televisionshow:The Muppets"
- 左对象：吉姆汉森
- 左对象属性：名称
- 关系：isCreatorOf
- 正确的对象：布偶
- 正确的对象属性：电视节目
尽管程序编译并运行，但我得到了几个异常，这些异常阻止了图形被填充。当我运行 Factory 程序时，它会读取我所有的三元组并将它们放入一个哈希集中，但随后会出现以下错误（10 次，但这只是 1 个示例）：
57338 [pool-10-thread-2] ERROR org.janusgraph.graphdb.database.StandardJanusGraph - Could not commit transaction [10] due to exception
org.janusgraph.diskstorage.locking.TemporaryLockingException: tx 0x181404008c7c already locked key-column ( 16-165-160-114-116- 30- 98-114- 97-110-100-116-121-112-229, 0) when tx 0x181408349015 tried to lock
at com.amazon.janusgraph.diskstorage.dynamodb.AbstractDynamoDBStore.acquireLock(AbstractDynamoDBStore.java:132)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore$4.call(MetricInstrumentedStore.java:155)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore$4.call(MetricInstrumentedStore.java:153)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore.runWithMetrics(MetricInstrumentedStore.java:217)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore.acquireLock(MetricInstrumentedStore.java:152)
at org.janusgraph.diskstorage.keycolumnvalue.KCVSProxy.acquireLock(KCVSProxy.java:52)
at org.janusgraph.diskstorage.BackendTransaction.acquireIndexLock(BackendTransaction.java:255)
at org.janusgraph.graphdb.database.StandardJanusGraph.prepareCommit(StandardJanusGraph.java:565)
at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:694)
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1363)
at org.janusgraph.graphdb.database.management.ManagementSystem.commit(ManagementSystem.java:235)
at com.amazon.janusgraph.creator.ObjectCreationCommand.run(ObjectCreationCommand.java:59)
at com.amazon.janusgraph.batch.BatchCommand.run(BatchCommand.java:34)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
接下来，抛出一个类似的异常：
57427 [pool-10-thread-10] ERROR com.amazon.janusgraph.example.MarvelGraphFactory - Error processing line Could not commit transaction due to exception during persistence tx 0x181404008c7c already locked key-column ( 16-165-160-114-116- 30- 98-114- 97-110-100-116-121-112-229, 0) when tx 0x181403f69b77 tried to lock
org.janusgraph.core.JanusGraphException: Could not commit transaction due to exception during persistence
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1374)
at org.janusgraph.graphdb.database.management.ManagementSystem.commit(ManagementSystem.java:235)
at com.amazon.janusgraph.creator.ObjectCreationCommand.run(ObjectCreationCommand.java:59)
at com.amazon.janusgraph.batch.BatchCommand.run(BatchCommand.java:34)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
Caused by: org.janusgraph.core.JanusGraphException: Unexpected exception
at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:798)
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.commit(StandardJanusGraphTx.java:1363)
... 6 more
Caused by: org.janusgraph.diskstorage.locking.TemporaryLockingException: tx 0x181404008c7c already locked key-column ( 16-165-160-114-116- 30- 98-114- 97-110-100-116-121-112-229, 0) when tx 0x181403f69b77 tried to lock
at com.amazon.janusgraph.diskstorage.dynamodb.AbstractDynamoDBStore.acquireLock(AbstractDynamoDBStore.java:132)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore$4.call(MetricInstrumentedStore.java:155)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore$4.call(MetricInstrumentedStore.java:153)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore.runWithMetrics(MetricInstrumentedStore.java:217)
at org.janusgraph.diskstorage.util.MetricInstrumentedStore.acquireLock(MetricInstrumentedStore.java:152)
at org.janusgraph.diskstorage.keycolumnvalue.KCVSProxy.acquireLock(KCVSProxy.java:52)
at org.janusgraph.diskstorage.BackendTransaction.acquireIndexLock(BackendTransaction.java:255)
at org.janusgraph.graphdb.database.StandardJanusGraph.prepareCommit(StandardJanusGraph.java:565)
at org.janusgraph.graphdb.database.StandardJanusGraph.commit(StandardJanusGraph.java:694)
... 7 more
然后抛出与模式相关的异常：
58030 [pool-10-thread-4] ERROR com.amazon.janusgraph.example.MarvelGraphFactory - Error processing line Adding this property for key [~T$SchemaName] and value [rtbrandtype] violates a uniqueness constraint [SystemIndex#~T$SchemaName]
org.janusgraph.core.SchemaViolationException: Adding this property for key [~T$SchemaName] and value [rtbrandtype] violates a uniqueness constraint [SystemIndex#~T$SchemaName]
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.addProperty(StandardJanusGraphTx.java:791)
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.addProperty(StandardJanusGraphTx.java:720)
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.makeSchemaVertex(StandardJanusGraphTx.java:847)
at org.janusgraph.graphdb.transaction.StandardJanusGraphTx.makePropertyKey(StandardJanusGraphTx.java:867)
at org.janusgraph.graphdb.types.StandardPropertyKeyMaker.make(StandardPropertyKeyMaker.java:100)
at com.amazon.janusgraph.creator.ObjectCreationCommand.run(ObjectCreationCommand.java:47)
at com.amazon.janusgraph.batch.BatchCommand.run(BatchCommand.java:34)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
最后，抛出了一个我真的不明白的异常：
58512 [pool-10-thread-8] ERROR com.amazon.janusgraph.example.MarvelGraphFactory - Error processing line Could not find type for id: 11529
java.lang.IllegalStateException: Could not find type for id: 11529
at com.google.common.base.Preconditions.checkState(Preconditions.java:197)
at org.janusgraph.graphdb.types.vertices.JanusGraphSchemaVertex.name(JanusGraphSchemaVertex.java:59)
at org.janusgraph.graphdb.types.vertices.JanusGraphSchemaVertex.asIndexType(JanusGraphSchemaVertex.java:177)
at org.janusgraph.graphdb.database.management.ManagementSystem.getGraphIndexDirect(ManagementSystem.java:412)
at org.janusgraph.graphdb.database.management.ManagementSystem.getGraphIndex(ManagementSystem.java:422)
at com.amazon.janusgraph.creator.ObjectCreationCommand.run(ObjectCreationCommand.java:55)
at com.amazon.janusgraph.batch.BatchCommand.run(BatchCommand.java:34)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1142)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:617)
at java.lang.Thread.run(Thread.java:745)
因为最终事务是 Null，所以会抛出 NullPointerException 并且永远不会提交事务；因此，我的图表已初始化但为空。
通常我不会发布这么长的问题，但似乎这些都与我创建的同一个类 ObjectCreationCommand 中的 4-5 行有关。
ObjectCreationCommand.java
package com.amazon.janusgraph.creator;
import com.amazon.janusgraph.example.TravelGraphFactory;
import com.codahale.metrics.MetricRegistry;
import org.apache.commons.lang.exception.ExceptionUtils;
import org.apache.tinkerpop.gremlin.process.traversal.dsl.graph.GraphTraversalSource;
import org.apache.tinkerpop.gremlin.structure.Vertex;
import org.janusgraph.core.JanusGraph;
import com.amazon.janusgraph.triple.Triple;
import org.janusgraph.core.Multiplicity;
import org.janusgraph.core.PropertyKey;
import org.janusgraph.core.schema.JanusGraphManagement;
import org.slf4j.Logger;
import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.util.Iterator;
import java.util.concurrent.TimeUnit;
public class ObjectCreationCommand implements Runnable {
public static JanusGraph graph;
private static Triple triple;
private static MetricRegistry REGISTRY;
public static Logger LOG;
private static final String TIMER_LINE = "TravelGraphFactory.line";
private static final String TIMER_CREATE = "TravelGraphFactory.create_";
private static final String COUNTER_GET = "TravelGraphFactory.get_";
public ObjectCreationCommand(JanusGraph graph, Triple triple, MetricRegistry REGISTRY, Logger LOG) {
this.graph = graph;
this.triple = triple;
this.REGISTRY = REGISTRY;
this.LOG = LOG;
}
@Override
public void run() {
JanusGraphManagement mgmt = graph.openManagement();
if (mgmt.getGraphIndex(triple.getRightObjectProperty()) == null) {
final PropertyKey hotelKey = mgmt.makePropertyKey(triple.getRightObjectProperty()).dataType(String.class).make();
mgmt.buildIndex(triple.getRightObjectProperty(), Vertex.class).addKey(hotelKey).unique().buildCompositeIndex();
}
if (mgmt.getEdgeLabel(triple.getRelationship()) == null) {
mgmt.makeEdgeLabel(triple.getRelationship()).multiplicity(Multiplicity.MANY2ONE).make();
}
if (mgmt.getGraphIndex(triple.getLeftObjectProperty()) == null) {
final PropertyKey brandTypeKey = mgmt.makePropertyKey(triple.getLeftObjectProperty()).dataType(String.class).make();
mgmt.buildIndex(triple.getLeftObjectProperty(), Vertex.class).addKey(brandTypeKey).unique().buildCompositeIndex();
}
mgmt.commit();
long start = System.currentTimeMillis();
String RIGHT_OBJECT_PROPERTY = triple.getRightObjectProperty();
Vertex rightObject = graph.addVertex();
rightObject.property(RIGHT_OBJECT_PROPERTY, triple.getRightObject());
REGISTRY.counter(COUNTER_GET + RIGHT_OBJECT_PROPERTY).inc();
String LEFT_OBJECT_PROPERTY = triple.getLeftObjectProperty();
Vertex leftObject = graph.addVertex();
rightObject.property(LEFT_OBJECT_PROPERTY, triple.getLeftObject());
REGISTRY.counter(COUNTER_GET + LEFT_OBJECT_PROPERTY).inc();
try {
processRelationship(graph, triple);
} catch (Throwable e) {
Throwable rootCause = ExceptionUtils.getRootCause(e);
String rootCauseMessage = null == rootCause ? "" : rootCause.getMessage();
LOG.error("Error processing line {} {}", e.getMessage(), rootCauseMessage, e);
}
long end = System.currentTimeMillis();
long time = end - start;
REGISTRY.timer(TIMER_CREATE + RIGHT_OBJECT_PROPERTY).update(time, TimeUnit.MILLISECONDS);
}
private static void processRelationship(JanusGraph graph, Triple triple) {
Vertex left = get(graph, triple.getLeftObjectProperty(), triple.getLeftObject());
if (null == left) {
REGISTRY.counter("error.missingLeftObject." + triple.getLeftObject()).inc();
left = graph.addVertex();
left.property(triple.getLeftObjectProperty(), triple.getLeftObject());
}
Vertex right = get(graph, triple.getRightObjectProperty(), triple.getRightObject());
if (null == right) {
REGISTRY.counter("error.missingRightObject." + triple.getRightObject()).inc();
right = graph.addVertex();
right.property(triple.getRightObjectProperty(), triple.getRightObject());
}
left.addEdge(triple.getRelationship(), right);
}
private static Vertex get(final JanusGraph graph, final String key, final String value) {
final GraphTraversalSource g = graph.traversal();
final Iterator<Vertex> it = g.V().has(key, value);
return it.hasNext() ? it.next() : null;
}
}
上面的异常表明所有错误都来自该类的第 47、55 或 59 行：
JanusGraphManagement mgmt = graph.openManagement();
if (mgmt.getGraphIndex(triple.getRightObjectProperty()) == null) {
[47] final PropertyKey hotelKey = mgmt.makePropertyKey(triple.getRightObjectProperty()).dataType(String.class).make();
mgmt.buildIndex(triple.getRightObjectProperty(), Vertex.class).addKey(hotelKey).unique().buildCompositeIndex();
}
if (mgmt.getEdgeLabel(triple.getRelationship()) == null) {
mgmt.makeEdgeLabel(triple.getRelationship()).multiplicity(Multiplicity.MANY2ONE).make();
}
[55] if (mgmt.getGraphIndex(triple.getLeftObjectProperty()) == null) {
final PropertyKey brandTypeKey = mgmt.makePropertyKey(triple.getLeftObjectProperty()).dataType(String.class).make();
mgmt.buildIndex(triple.getLeftObjectProperty(), Vertex.class).addKey(brandTypeKey).unique().buildCompositeIndex();
}
[59] mgmt.commit();
谁能帮助确定我在这门课上做错了什么？无论我在做什么都是锁定表并创建模式问题。