CODEWITHSUNDEEP
neo4jcypher
Debajyoti Roy
Debajyoti Roy

Reputation: 995

Getting org.neo4j.graphdb.NotFoundException during Cypher with count(). What is causing it?

We have a cypher as follows:

START n=node:ACCOUNTS(ACCOUNT_ID={id}) 
MATCH (n)-[:PROVIDER]->(p)<-[r:ALERT]-(m) 
RETURN p.ID as pID, p.FIRST_NAME? as pFN, p.LAST_NAME? as pLN, count(r) as alerts

This works fine all the time even under heavy load. However we sometimes delete relationships in separate threads(within a transaction).

With extreme bad timing, we are getting this error:

******Relationship 13407007 not found
org.neo4j.graphdb.NotFoundException: Relationship 13407007 not found
        at org.neo4j.kernel.impl.core.NodeManager.__AW_getRelationshipForProxy(NodeManager.java:675)
        at org.neo4j.kernel.impl.core.NodeManager.getRelationshipForProxy(NodeManager.java)
        at org.neo4j.kernel.InternalAbstractGraphDatabase$5.lookupRelationship(InternalAbstractGraphDatabase.java:689)
        at org.neo4j.kernel.impl.core.RelationshipProxy.getOtherNode(RelationshipProxy.java:73)
        at org.neo4j.cypher.internal.pipes.matching.FilteringIterable$FilteringIterator.spoolToNextInLine(FilteringIterable.scala:58)
        at org.neo4j.cypher.internal.pipes.matching.FilteringIterable$FilteringIterator.next(FilteringIterable.scala:49)
        at org.neo4j.cypher.internal.pipes.matching.FilteringIterable$FilteringIterator.next(FilteringIterable.scala:35)
        at scala.collection.convert.Wrappers$IteratorWrapper.next(Wrappers.scala:30)
        at org.neo4j.kernel.impl.traversal.TraversalBranchImpl.__AW_next(TraversalBranchImpl.java:137)
        at org.neo4j.kernel.impl.traversal.TraversalBranchImpl.next(TraversalBranchImpl.java)
        at org.neo4j.kernel.impl.traversal.TraversalBranchWithState.next(TraversalBranchWithState.java:32)
        at org.neo4j.kernel.PreorderDepthFirstSelector.__AW_next(PreorderDepthFirstSelector.java:52)
        at org.neo4j.kernel.PreorderDepthFirstSelector.next(PreorderDepthFirstSelector.java)
        at org.neo4j.kernel.impl.traversal.TraverserIterator.fetchNextOrNull(TraverserIterator.java:65)
        at org.neo4j.kernel.impl.traversal.TraverserIterator.fetchNextOrNull(TraverserIterator.java:34)
        at org.neo4j.helpers.collection.PrefetchingIterator.hasNext(PrefetchingIterator.java:55)
        at scala.collection.convert.Wrappers$JIteratorWrapper.hasNext(Wrappers.scala:41)
        at scala.collection.Iterator$$anon$13.__AW_hasNext(Iterator.scala:371)
        at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala)
        at scala.collection.Iterator$$anon$13.__AW_hasNext(Iterator.scala:371)
        at scala.collection.Iterator$$anon$13.hasNext(Iterator.scala)
        at scala.collection.Iterator$$anon$11.hasNext(Iterator.scala:327)
        at scala.collection.Iterator$class.__AW_foreach(Iterator.scala:727)
        at scala.collection.Iterator$class.foreach(Iterator.scala)
        at scala.collection.AbstractIterator.foreach(Iterator.scala:1156)
        at org.neo4j.cypher.internal.pipes.EagerAggregationPipe.internalCreateResults(EagerAggregationPipe.scala:76)
        at org.neo4j.cypher.internal.pipes.PipeWithSource.createResults(Pipe.scala:69)
        at org.neo4j.cypher.internal.pipes.PipeWithSource.createResults(Pipe.scala:66)
        at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl.org$neo4j$cypher$internal$executionplan$ExecutionPlanImpl$$prepareStateAndResult(ExecutionPlanImpl
.scala:164)
        at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl$$anonfun$getLazyReadonlyQuery$1.apply(ExecutionPlanImpl.scala:139)
        at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl$$anonfun$getLazyReadonlyQuery$1.apply(ExecutionPlanImpl.scala:138)
        at org.neo4j.cypher.internal.executionplan.ExecutionPlanImpl.execute(ExecutionPlanImpl.scala:38)
        at org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:72)
        at org.neo4j.cypher.ExecutionEngine.execute(ExecutionEngine.scala:76)
        at org.neo4j.cypher.javacompat.ExecutionEngine.execute(ExecutionEngine.java:79)

We don't start a transaction for the cypher execution. Please advice on what could be causing this and a fix. This is with Neo4j Community 1.9.3

Upvotes: 0

Views: 832

Answers (1)

Debajyoti Roy
Debajyoti Roy

Reputation: 995

Background: Cypher is not taking read locks, this might be fixed in v2.1

The tried and tested solution: catch NotFoundexception, sleep and retry the query

Another solution: (not sure if its really a solution- we are testing further): wrap the method inside a transaction

Upvotes: 1

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