编辑-尝试调试

Question

对于我的数据导入，我突然收到以下错误：

neo4j.exceptions.DatabaseError: NOT PART OF CHAIN! RelationshipTraversalCursor[id=328769435, open state with: denseNode=false, next=328769435, mode=regular, underlying record=Relationship[328769435,used=false,source=0,target=0,type=0,sPrev=0,sNext=0,tPrev=0,tNext=0,prop=0,secondaryUnitId=-1,!sFirst,!tFirst] ]

此错误实际上是什么意思？我该如何进一步调试呢？

我还没有找到任何文档。

debug.log的最后一部分（StackOverflow不允许更多）：

2018-07-19 14:29:57.551+0000 ERROR [o.n.b.v.r.ErrorReporter] Client 

...
org.neo4j.cypher.internal.runtime.slotted.pipes.ApplySlottedPipe$$anonfun$internalCreateResults$1.apply(ApplySlottedPipe.scala:34)
        at scala.collection.Iterator$$anon$12.nextCur(Iterator.scala:435)
        at scala.collection.Iterator$$anon$12.hasNext(Iterator.scala:441)
        at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:409)
        at scala.collection.Iterator$class.foreach(Iterator.scala:891)
        at scala.collection.AbstractIterator.foreach(Iterator.scala:1334)
        at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:59)
        at scala.collection.immutable.VectorBuilder.$plus$plus$eq(Vector.scala:732)
        at scala.collection.immutable.VectorBuilder.$plus$plus$eq(Vector.scala:708)
        at scala.collection.TraversableOnce$class.to(TraversableOnce.scala:310)
        at scala.collection.AbstractIterator.to(Iterator.scala:1334)
        at scala.collection.TraversableOnce$class.toIndexedSeq(TraversableOnce.scala:300)
        at scala.collection.AbstractIterator.toIndexedSeq(Iterator.scala:1334)
        at org.neo4j.cypher.internal.runtime.slotted.pipes.EagerSlottedPipe.internalCreateResults(EagerSlottedPipe.scala:40)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:76)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.runtime.interpreted.pipes.PipeWithSource.createResults(Pipe.scala:72)
        at org.neo4j.cypher.internal.compatibility.v3_4.runtime.executionplan.BaseExecutionResultBuilderFactory$BaseExecutionWorkflowBuilder.createResults(DefaultExecutionResultBuilderFactory.scala:105)
        at org.neo4j.cypher.internal.compatibility.v3_4.runtime.executionplan.BaseExecutionResultBuilderFactory$BaseExecutionWorkflowBuilder.build(DefaultExecutionResultBuilderFactory.scala:77)
        at org.neo4j.cypher.internal.compatibility.v3_4.runtime.BuildInterpretedExecutionPlan$$anonfun$getExecutionPlanFunction$1.apply(BuildInterpretedExecutionPlan.scala:97)
        at org.neo4j.cypher.internal.compatibility.v3_4.runtime.BuildInterpretedExecutionPlan$$anonfun$getExecutionPlanFunction$1.apply(BuildInterpretedExecutionPlan.scala:80)
        at org.neo4j.cypher.internal.BuildSlottedExecutionPlan$SlottedExecutionPlan.run(BuildSlottedExecutionPlan.scala:152)
        at org.neo4j.cypher.internal.compatibility.LatestRuntimeVariablePlannerCompatibility$ExecutionPlanWrapper$$anonfun$run$1.apply(LatestRuntimeVariablePlannerCompatibility.scala:128)
        at org.neo4j.cypher.internal.compatibility.LatestRuntimeVariablePlannerCompatibility$ExecutionPlanWrapper$$anonfun$run$1.apply(LatestRuntimeVariablePlannerCompatibility.scala:124)
        at org.neo4j.cypher.exceptionHandler$runSafely$.apply(exceptionHandler.scala:89)
        at org.neo4j.cypher.internal.compatibility.LatestRuntimeVariablePlannerCompatibility$ExecutionPlanWrapper.run(LatestRuntimeVariablePlannerCompatibility.scala:124)
        at org.neo4j.cypher.internal.PreparedPlanExecution.execute(PreparedPlanExecution.scala:29)
        at org.neo4j.cypher.internal.ExecutionEngine.execute(ExecutionEngine.scala:119)
        at org.neo4j.cypher.internal.javacompat.ExecutionEngine.executeQuery(ExecutionEngine.java:61)
        at org.neo4j.bolt.v1.runtime.TransactionStateMachineSPI$1.start(TransactionStateMachineSPI.java:144)
        at org.neo4j.bolt.v1.runtime.TransactionStateMachine$State.startExecution(TransactionStateMachine.java:446)
        at org.neo4j.bolt.v1.runtime.TransactionStateMachine$State$2.run(TransactionStateMachine.java:343)
        at org.neo4j.bolt.v1.runtime.TransactionStateMachine.run(TransactionStateMachine.java:81)
        at org.neo4j.bolt.v1.runtime.BoltStateMachine$State$2.run(BoltStateMachine.java:456)
        at org.neo4j.bolt.v1.runtime.BoltStateMachine.run(BoltStateMachine.java:222)
        at org.neo4j.bolt.v1.messaging.BoltMessageRouter.lambda$onRun$3(BoltMessageRouter.java:93)
        at org.neo4j.bolt.runtime.MetricsReportingBoltConnection.lambda$enqueue$0(MetricsReportingBoltConnection.java:69)
        at org.neo4j.bolt.runtime.DefaultBoltConnection.processNextBatch(DefaultBoltConnection.java:193)
        at org.neo4j.bolt.runtime.MetricsReportingBoltConnection.processNextBatch(MetricsReportingBoltConnection.java:87)
        at org.neo4j.bolt.runtime.DefaultBoltConnection.processNextBatch(DefaultBoltConnection.java:143)
        at org.neo4j.bolt.runtime.ExecutorBoltScheduler.executeBatch(ExecutorBoltScheduler.java:163)
        at org.neo4j.bolt.runtime.ExecutorBoltScheduler.lambda$null$0(ExecutorBoltScheduler.java:145)
        at java.util.concurrent.CompletableFuture$AsyncSupply.run(CompletableFuture.java:1590)
        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:748)

对于以前成功导入的文件，现在也会发生这种情况。

这必须与我的密码查询有关，因为当我将其减少到绝对最小值时它可以工作，但是了解该错误将有所帮助。

编辑-尝试调试

现在，我对这个错误很困惑。

使用我脚本中的超级最小Cypher查询，一切正常：

WITH $custom_dict as pubmed_list
UNWIND pubmed_list as article
    MERGE (p:Publication {pmid: COALESCE (article.pmid, 'NO-PMID')})
    ON CREATE SET p.title = article.article_title, p.journal_title = article.journal_title, p.db = 'pubmed'

但是，当我添加此内容时：

    MERGE (dc:Date { year: COALESCE (article.year_revised, 'NO-YEAR-COMPLETION') })
    MERGE (p)-[:COMPLETED]->(dc)

    MERGE (dr:Date { year: COALESCE (article.year_completed, 'NO-YEAR-REVISION')})
    MERGE (p)-[:REVISED]->(dr)

我为UNWINDing传递的字典看起来也很好：

编辑2-一致性检查

运行一致性检查后：

$ "$NEO4J_HOME"/bin/neo4j-admin check-consistency --database=graph.db

它是这样开始的：

2018-07-20 08:41:15.337+0000 INFO [o.n.k.i.s.f.RecordFormatSelector] Selected RecordFormat:StandardV3_4[v0.A.9] record format from store /Users/rich/Library/Application Support/Neo4j Desktop/Application/neo4jDatabases/database-4ca696a4-add3-4f69-a97b-1b89ce8e854b/installation-3.4.0/data/databases/graph.db
2018-07-20 08:41:15.340+0000 INFO [o.n.k.i.s.f.RecordFormatSelector] Format not configured. Selected format from the store: RecordFormat:StandardV3_4[v0.A.9]

然后我得到了数千个：

2018-07-20 08:42:49.837+0000 ERROR [o.n.c.ConsistencyCheckService] The referenced relationship group record is not in use.
    Node[145800979,used=true,group=8661147,prop=275750014,labels=Inline(0x1000000000:[0]),light,secondaryUnitId=-1]
    Inconsistent with: RelationshipGroup[8661147,type=0,out=0,in=0,loop=0,prev=-1,next=0,used=false,owner=0,secondaryUnitId=-1]

然后继续：

...  10%
....................  20%
................2018-07-20 08:49:01.023+0000 ERROR [o.n.c.ConsistencyCheckService] This record should be the first in the source chain, but the source node does not reference this record.

现在它可以永久运行，并具有前面描述的错误，如下所示：

Inconsistent with: Node[6577082,used=true,rel=329016678,prop=11682171,labels=Inline(0x1000000000:[0]),light,secondaryUnitId=-1]
2018-07-20 09:07:05.171+0000 ERROR [o.n.c.ConsistencyCheckService] This record should be the first in the target chain, but the target node does not reference this record.
    Relationship[314188818,used=true,source=140353187,target=78456590,type=4,sPrev=314188819,sNext=314188812,tCount=32,tNext=301551374,prop=-1,secondaryUnitId=-1,!sFirst, tFirst]

这：

2018-07-20 09:08:14.715+0000 ERROR [o.n.c.ConsistencyCheckService] The next record in the target chain does not have this record as its previous record.
    Relationship[192261,used=true,source=28336,target=5180,type=4,sPrev=192264,sNext=192260,tPrev=191008,tNext=184760,prop=-1,secondaryUnitId=-1,!sFirst,!tFirst]
    Inconsistent with: Relationship[184760,used=true,source=24761,target=5180,type=4,sPrev=184750,sNext=184761,tPrev=184738,tNext=192261,prop=-1,secondaryUnitId=-1,!sFirst,!tFirst]

这对我的数据库意味着什么，我该如何解决？

Answer 1

好像数据库已损坏。通常是由于Neo4j运行时磁盘空间不足（现在应该使用最新版本来缓解），或者是由于复制数据库（文件复制，而不是使用neo4j-admin backup的热备份功能）或在Neo4j运行时修改文件。

您应该对数据库进行备份（禁用一致性检查，您将不再需要），然后使用store copy utils从备份中重建数据库，然后从中还原实例（或集群）。重建的数据存储。

重建存储会跳过所有损坏的记录，因此您可能要在操作完成后检查数据。

Answer 2

我可以在一个测试中重现此错误，只需在单个事务中调用2个线程的遍历即可。因此，从neo4j有关事务的文档中，不建议使用这种访问模式。

https://neo4j.com/docs/java-reference/4.1/javadocs/org/neo4j/graphdb/Transaction.html

Note that transactions should be used by a single thread only. It is generally not safe to use a transaction from multiple threads. Doing so will lead to undefined behavior.

或者，如果遍历陷入无限循环或正在等待锁定（检查线程转储），那么这也可能表明在具有多个线程的单个事务上运行遍历或使用来自其他交易中的其他未提交交易。

Neo4j-不属于链条！关系Traversal游标

编辑-尝试调试

编辑2-一致性检查

2 个答案: