我使用 Neo4j 构建了一个图形，它由大约 1000 个节点和大约 270,000 个关系组成。该图是一个航类网络(机场是节点，航类是关系)，因此节点与节点之间存在许多关系。我确定某些查询中也有很多循环(我不确定这是否有问题)。无论如何，某些查询工作正常，如下所示:
start a=node(1), b=node(2) match p=a-[:flys_to*..1]->b return p;
start a=node(1), b=node(2) match p=shortestPath(a-[:flys_to]->b) return p;
但是当我尝试其他更复杂的查询时，没有友好的错误信息；它只是挂起大约 3 分钟(取决于我在其中搜索的两个节点)并返回“未定义”。
挂起的查询之一如下所示:
start a=node(1), b=node(2) match p=a-[:flys_to*..2]->b return p;
另外，一个有趣的旁注是，当我输入以下查询时，它会立即返回“未定义”:
start a=node(1), b=node(2) match p=a-[:flys_to]->b return p;
这是否有意义，或者有人对我可以从哪里开始进行故障排除有任何想法？
有关此特定问题的更多信息
这是数据库的压缩文件:http://www.opensourcebanking.org/neo4j/
我在 VMware 上的虚拟环境中运行它。主机是 OSX 10.8.2， guest 是 Windows Server 2012。 JRE 是 1.6.0_38 .另外，我在节点属性“iata”和关系属性“flys_to”上设置了自动索引。
以下是一些 Cypher 查询及其相关的记录消息:
以下查询几乎立即返回“未定义”:
start a=node(353), b=node(295)
match p=a-->b
return p;
这是我在日志中得到的:
SEVERE: The exception contained within MappableContainerException could not be mapped to a response, re-throwing to the HTTP container
org.neo4j.helpers.ThisShouldNotHappenError: Developer: Andres claims that: Unexpected traversal state encountered
at org.neo4j.cypher.internal.pipes.matching.BidirectionalTraversalMatcher$StepCollisionDetector.includePath(BidirectionalTraversalMatcher.scala:101)
at org.neo4j.kernel.StandardBranchCollisionDetector.evaluate(StandardBranchCollisionDetector.java:74)
at org.neo4j.kernel.StandardBranchCollisionDetector.evaluate(StandardBranchCollisionDetector.java:37)
at org.neo4j.kernel.impl.traversal.BidirectionalTraverserIterator.fetchNextOrNull(BidirectionalTraverserIterator.java:157)
at org.neo4j.kernel.impl.traversal.BidirectionalTraverserIterator.fetchNextOrNull(BidirectionalTraverserIterator.java:41)
at org.neo4j.helpers.collection.PrefetchingIterator.hasNext(PrefetchingIterator.java:55)
at scala.collection.JavaConversions$JIteratorWrapper.hasNext(JavaConversions.scala:574)
at scala.collection.Iterator$$anon$21.hasNext(Iterator.scala:371)
at scala.collection.Iterator$$anon$21.hasNext(Iterator.scala:371)
at scala.collection.Iterator$$anon$19.hasNext(Iterator.scala:334)
at scala.collection.Iterator$$anon$19.hasNext(Iterator.scala:334)
at scala.collection.Iterator$$anon$19.hasNext(Iterator.scala:334)
at org.neo4j.cypher.internal.ClosingIterator$$anonfun$hasNext$1.apply$mcZ$sp(ClosingIterator.scala:36)
at org.neo4j.cypher.internal.ClosingIterator$$anonfun$hasNext$1.apply(ClosingIterator.scala:35)
at org.neo4j.cypher.internal.ClosingIterator$$anonfun$hasNext$1.apply(ClosingIterator.scala:35)
at org.neo4j.cypher.internal.ClosingIterator.failIfThrows(ClosingIterator.scala:87)
at org.neo4j.cypher.internal.ClosingIterator.hasNext(ClosingIterator.scala:35)
at scala.collection.Iterator$class.foreach(Iterator.scala:660)
at org.neo4j.cypher.internal.ClosingIterator.foreach(ClosingIterator.scala:31)
at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)
at scala.collection.mutable.ListBuffer.$plus$plus$eq(ListBuffer.scala:128)
at scala.collection.TraversableOnce$class.toList(TraversableOnce.scala:242)
at org.neo4j.cypher.internal.ClosingIterator.toList(ClosingIterator.scala:31)
at org.neo4j.cypher.PipeExecutionResult.createTimedResults(PipeExecutionResult.scala:73)
at org.neo4j.cypher.PipeExecutionResult.dumpToString(PipeExecutionResult.scala:80)
at org.neo4j.cypher.PipeExecutionResult.dumpToString(PipeExecutionResult.scala:125)
at org.neo4j.cypher.javacompat.ExecutionResult.dumpToString(ExecutionResult.java:91)
at org.neo4j.shell.kernel.apps.Start.exec(Start.java:71)
at org.neo4j.shell.kernel.apps.ReadOnlyGraphDatabaseApp.execute(ReadOnlyGraphDatabaseApp.java:32)
at org.neo4j.shell.impl.AbstractAppServer.interpretLine(AbstractAppServer.java:115)
at org.neo4j.shell.kernel.GraphDatabaseShellServer.interpretLine(GraphDatabaseShellServer.java:92)
at org.neo4j.shell.impl.AbstractClient.evaluate(AbstractClient.java:130)
at org.neo4j.shell.impl.AbstractClient.evaluate(AbstractClient.java:114)
at org.neo4j.server.webadmin.console.ShellSession.evaluate(ShellSession.java:101)
at org.neo4j.server.webadmin.rest.console.ConsoleService.exec(ConsoleService.java:125)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(Unknown Source)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(Unknown Source)
at java.lang.reflect.Method.invoke(Unknown Source)
at com.sun.jersey.spi.container.JavaMethodInvokerFactory$1.invoke(JavaMethodInvokerFactory.java:60)
at com.sun.jersey.server.impl.model.method.dispatch.AbstractResourceMethodDispatchProvider$ResponseOutInvoker._dispatch(AbstractResourceMethodDispatchProvider.java:205)
at com.sun.jersey.server.impl.model.method.dispatch.ResourceJavaMethodDispatcher.dispatch(ResourceJavaMethodDispatcher.java:75)
at com.sun.jersey.server.impl.uri.rules.HttpMethodRule.accept(HttpMethodRule.java:288)
at com.sun.jersey.server.impl.uri.rules.ResourceClassRule.accept(ResourceClassRule.java:108)
at com.sun.jersey.server.impl.uri.rules.RightHandPathRule.accept(RightHandPathRule.java:147)
at com.sun.jersey.server.impl.uri.rules.RootResourceClassesRule.accept(RootResourceClassesRule.java:84)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1469)
at com.sun.jersey.server.impl.application.WebApplicationImpl._handleRequest(WebApplicationImpl.java:1400)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1349)
at com.sun.jersey.server.impl.application.WebApplicationImpl.handleRequest(WebApplicationImpl.java:1339)
at com.sun.jersey.spi.container.servlet.WebComponent.service(WebComponent.java:416)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:537)
at com.sun.jersey.spi.container.servlet.ServletContainer.service(ServletContainer.java:699)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:820)
at org.mortbay.jetty.servlet.ServletHolder.handle(ServletHolder.java:511)
at org.mortbay.jetty.servlet.ServletHandler.handle(ServletHandler.java:390)
at org.mortbay.jetty.servlet.SessionHandler.handle(SessionHandler.java:182)
at org.mortbay.jetty.handler.ContextHandler.handle(ContextHandler.java:765)
at org.mortbay.jetty.handler.HandlerCollection.handle(HandlerCollection.java:114)
at org.mortbay.jetty.handler.HandlerWrapper.handle(HandlerWrapper.java:152)
at org.mortbay.jetty.Server.handle(Server.java:326)
at org.mortbay.jetty.HttpConnection.handleRequest(HttpConnection.java:542)
at org.mortbay.jetty.HttpConnection$RequestHandler.content(HttpConnection.java:943)
at org.mortbay.jetty.HttpParser.parseNext(HttpParser.java:756)
at org.mortbay.jetty.HttpParser.parseAvailable(HttpParser.java:218)
at org.mortbay.jetty.HttpConnection.handle(HttpConnection.java:404)
at org.mortbay.io.nio.SelectChannelEndPoint.run(SelectChannelEndPoint.java:410)
at org.mortbay.thread.QueuedThreadPool$PoolThread.run(QueuedThreadPool.java:582)
以下查询工作正常。它返回 426 行并且没有记录任何内容。
start a=node(353), b=node(295)
match p=a-[:flys_to*..1]->b
return p;
以下查询在大约 10-15 分钟后返回“未定义”:
start a=node(353), b=node(295)
match p=a-[:flys_to*..2]->b
return p;
日志:
SEVERE: The exception contained within MappableContainerException could not be mapped to a response, re-throwing to the HTTP container
java.lang.OutOfMemoryError: Java heap space
at org.neo4j.cypher.internal.pipes.matching.AddedHistory.toSeq(History.scala:87)
at org.neo4j.cypher.internal.pipes.matching.AddedHistory.toMap(History.scala:75)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.isMatchSoFar(PatternMatcher.scala:166)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.org$neo4j$cypher$internal$pipes$matching$PatternMatcher$$traverseNextNodeFromRelationship(PatternMatcher.scala:98)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher$$anonfun$4.apply(PatternMatcher.scala:150)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher$$anonfun$4.apply(PatternMatcher.scala:150)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:175)
at scala.collection.immutable.Stream$$anonfun$map$1.apply(Stream.scala:175)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:634)
at scala.collection.immutable.Stream$Cons.tail(Stream.scala:626)
at scala.collection.immutable.Stream.foldLeft(Stream.scala:302)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.traverseRelationship(PatternMatcher.scala:150)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.traverseNextSpecificNode(PatternMatcher.scala:61)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.traverseNode(PatternMatcher.scala:72)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.foreach(PatternMatcher.scala:36)
at scala.collection.generic.Growable$class.$plus$plus$eq(Growable.scala:48)
at scala.collection.mutable.ArrayBuffer.$plus$plus$eq(ArrayBuffer.scala:99)
at scala.collection.TraversableOnce$class.toBuffer(TraversableOnce.scala:250)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.toBuffer(PatternMatcher.scala:28)
at scala.collection.TraversableLike$class.toStream(TraversableLike.scala:571)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.toStream(PatternMatcher.scala:28)
at scala.collection.TraversableLike$class.toIterator(TraversableLike.scala:570)
at org.neo4j.cypher.internal.pipes.matching.PatternMatcher.toIterator(PatternMatcher.scala:28)
at scala.collection.Iterator$$anon$21.hasNext(Iterator.scala:371)
at scala.collection.Iterator$$anon$19.hasNext(Iterator.scala:334)
at scala.collection.Iterator$$anon$19.hasNext(Iterator.scala:334)
at scala.collection.Iterator$$anon$19.hasNext(Iterator.scala:334)
at org.neo4j.cypher.internal.ClosingIterator$$anonfun$hasNext$1.apply$mcZ$sp(ClosingIterator.scala:36)
at org.neo4j.cypher.internal.ClosingIterator$$anonfun$hasNext$1.apply(ClosingIterator.scala:35)
at org.neo4j.cypher.internal.ClosingIterator$$anonfun$hasNext$1.apply(ClosingIterator.scala:35)
at org.neo4j.cypher.internal.ClosingIterator.failIfThrows(ClosingIterator.scala:87)
at org.neo4j.cypher.internal.ClosingIterator.hasNext(ClosingIterator.scala:35)
最佳答案
您是否尝试使用 shortestPath或 allShortestPaths对于您的查询？
start a=node(1), b=node(2) match p=allShortestPaths(a-[:flys_to*..2]->b) return p;
+--------------------------------------------------------------------------------------------------------+
| p |
+--------------------------------------------------------------------------------------------------------+
| [Node[1]{iata:"ABE"},:flys_to[224044] {},Node[546]{iata:"SFO"},:flys_to[24211] {},Node[2]{iata:"ABI"}] |
| [Node[1]{iata:"ABE"},:flys_to[224044] {},Node[546]{iata:"SFO"},:flys_to[24210] {},Node[2]{iata:"ABI"}] |
....
| [Node[1]{iata:"ABE"},:flys_to[66032] {},Node[146]{iata:"DFW"},:flys_to[1] {},Node[2]{iata:"ABI"}] |
| [Node[1]{iata:"ABE"},:flys_to[66032] {},Node[146]{iata:"DFW"},:flys_to[0] {},Node[2]{iata:"ABI"}] |
+--------------------------------------------------------------------------------------------------------+
28 rows
20 ms
start a=node(1), b=node(2) match p=shortestPath(a-[:flys_to*..2]->b) return p;
+--------------------------------------------------------------------------------------------------------+
| p |
+--------------------------------------------------------------------------------------------------------+
| [Node[1]{iata:"ABE"},:flys_to[224044] {},Node[546]{iata:"SFO"},:flys_to[24211] {},Node[2]{iata:"ABI"}] |
+--------------------------------------------------------------------------------------------------------+
1 row
1 ms
关于neo4j - Neo4j 中的密码查询返回 'undefined'，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/14330864/