知识库

错误“记录 ID 65536 超出范围 [0, 65535]”的解释

运行创建新关系类型的 Cypher 语句时，例如

MERGE (n1:Person {id:1})-[r:knows]->(n2:Person {id:2})

可能会遇到一个错误，该错误记录在 $NEO4J_HOME/logs/debug.log 中，如下所示

2017-10-30 17:08:29.741+0000 ERROR [o.n.b.v.r.ErrorReporter] Client triggered an unexpected error [UnknownError]: Could not create token, reference 63c2e7ef-6f5b-4834-b2a8-fe74cac3a50a. Could not create token
org.neo4j.graphdb.TransactionFailureException: Could not create token
        at org.neo4j.kernel.impl.core.DelegatingTokenHolder.getOrCreateId(DelegatingTokenHolder.java:85)
        at org.neo4j.kernel.impl.api.store.StorageLayer.relationshipTypeGetOrCreateForName(StorageLayer.java:376)
        at org.neo4j.kernel.impl.api.StateHandlingStatementOperations.relationshipTypeGetOrCreateForName(StateHandlingStatementOperations.java:1384)
        at org.neo4j.kernel.impl.api.DataIntegrityValidatingStatementOperations.relationshipTypeGetOrCreateForName(DataIntegrityValidatingStatementOperations.java:86)
        at org.neo4j.kernel.impl.api.OperationsFacade.relationshipTypeGetOrCreateForName(OperationsFacade.java:774)
        at org.neo4j.cypher.internal.spi.v3_3.TransactionBoundQueryContext.getOrCreateRelTypeId(TransactionBoundQueryContext.scala:114)
        at org.neo4j.cypher.internal.compatibility.v3_3.ExceptionTranslatingQueryContext$$anonfun$getOrCreateRelTypeId$1.apply$mcI$sp(ExceptionTranslatingQueryContext.scala:203)
        ...
        at org.neo4j.bolt.v1.runtime.concurrent.RunnableBoltWorker.run(RunnableBoltWorker.java:96)
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511)
        at java.util.concurrent.FutureTask.run(FutureTask.java:266)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
        at org.neo4j.helpers.NamedThreadFactory$2.run(NamedThreadFactory.java:109)
Caused by: org.neo4j.kernel.impl.store.id.validation.IdCapacityExceededException: Record id 65536 is out of range [0, 65535]
        at org.neo4j.kernel.impl.store.id.validation.IdValidator.assertIdWithinCapacity(IdValidator.java:88)
        at org.neo4j.kernel.impl.store.id.validation.IdValidator.assertValidId(IdValidator.java:67)
        at org.neo4j.kernel.impl.store.id.IdGeneratorImpl.nextId(IdGeneratorImpl.java:143)
        at org.neo4j.kernel.impl.core.DefaultRelationshipTypeCreator.createKey(DefaultRelationshipTypeCreator.java:40)
        at org.neo4j.kernel.impl.core.IsolatedTransactionTokenCreator.getOrCreate(IsolatedTransactionTokenCreator.java:59)
        at org.neo4j.kernel.impl.core.DelegatingTokenHolder.createToken(DelegatingTokenHolder.java:103)
        at org.neo4j.kernel.impl.core.DelegatingTokenHolder.getOrCreateId(DelegatingTokenHolder.java:76)
        ... 49 more

其中关键部分是 记录 ID 65536 超出范围 [0, 65535] 的引用

此错误是由于达到图数据库中的关系类型最大数量而导致的。当前限制为 65536。请注意，这专门针对“关系类型”，即用于命名关系的标识符。此限制不适用于节点之间关系的数量或图中关系的总数。

遇到此错误时运行

call db.relationshipTypes() yield relationshipType return count(relationshipType) as numRelTypes;

将返回

+-------------+
| numRelTypes |
+-------------+
| 65536       |
+-------------+

要解决此错误，需要删除不再与任何节点关联的关系类型。由于目前没有 Cypher 命令可以做到这一点，因此需要运行 copy-store.sh。此命令将读取离线 graph.db 并准备一个新的 graph.db，但会排除不再使用的关系类型/属性。