Hi!
While I was writing unit tests for my app I noticed this exception when
testing more concurrent sessions than connectionPoolSize in javascript
neo4j-driver.
Versions:
neo4j - dockerized 3.0.1, image neo4j:3.0
neo4j-driver - 1.0.1
nodejs - tested on 6.6.0 and 6.2.1
Error:
2016-09-27 19:21:41.296+0000 ERROR [o.n.b.v.t.BoltProtocolV1] Failed to
write response to driver
java.lang.NullPointerException
at org.neo4j.bolt.v1.transport.ChunkedOutput.ensure(ChunkedOutput.java:156)
at
org.neo4j.bolt.v1.transport.ChunkedOutput.writeShort(ChunkedOutput.java:90)
at
org.neo4j.bolt.v1.packstream.PackStream$Packer.packStructHeader(PackStream.java:304)
at
org.neo4j.bolt.v1.messaging.PackStreamMessageFormatV1$Writer.handleSuccessMessage(PackStreamMessageFormatV1.java:145)
at
org.neo4j.bolt.v1.messaging.msgprocess.MessageProcessingCallback.completed(MessageProcessingCallback.java:102)
at
org.neo4j.bolt.v1.messaging.msgprocess.MessageProcessingCallback.completed(MessageProcessingCallback.java:31)
at
org.neo4j.bolt.v1.runtime.internal.SessionStateMachine.after(SessionStateMachine.java:823)
at
org.neo4j.bolt.v1.runtime.internal.SessionStateMachine.reset(SessionStateMachine.java:699)
at
org.neo4j.bolt.v1.runtime.internal.concurrent.SessionWorkerFacade.lambda$reset$6(SessionWorkerFacade.java:87)
at
org.neo4j.bolt.v1.runtime.internal.concurrent.SessionWorker.execute(SessionWorker.java:116)
at
org.neo4j.bolt.v1.runtime.internal.concurrent.SessionWorker.run(SessionWorker.java:77)
at java.lang.Thread.run(Thread.java:745)
I can reproduce this error on fresh DB using this code:
const _ = require('lodash'),
neo4j = require('neo4j-driver').v1;
const driver = neo4j.driver('bolt://localhost:7687',
neo4j.auth.basic('neo4j',
'neo4j'),
{connectionPoolSize: 1});
for (let i = 0; i < 100; i++) {
let session = driver.session();
session
.run('create (u:User {id: {id}}) return u', {id: _.random(100000)})
.then(records => {
console.log('=====================NUMBER'+i+'=======================');
console.log(records)
console.log('==============================================');
session.close();
})
.catch(err => {
console.error(err);
session.close();
});
}
The same problem appears using observer:
const _ = require('lodash'),
neo4j = require('neo4j-driver').v1;
const driver = neo4j.driver('bolt://localhost:7687',
neo4j.auth.basic('neo4j',
'neo4j'),
{connectionPoolSize: 1});
for (let i = 0; i < 100; i++) {
let session = driver.session();
session
.run('create (u:User {id: {id}}) return u', {id: _.random(100000)})
.subscribe({
onNext(record) {
},
onCompleted(summary) {
console.log('finished number ' + i);
session.close();
},
onError(err) {
console.error(err, 'itaration number' + i);
}
});
}
After removing session.close() this problem disappears in both cases.
When using lower number of session e.g. 5, then the same problem appears
after few scripts run. However, all records are returned properly.
I wouldn't notice this if next test in my suite sometimes didn't strangely
fail with timeout or even exception shown below when using "match
(u:Testing) detach delete u" on afterEach hook.
2016-09-27 20:19:32.868+0000 ERROR [o.n.b.v.r.i.ErrorReporter] Client
triggered an unexpected error [UnknownError]:
Property[1075,used=false,prev=-1,next=-1] not in use. See debug.log for
more details, reference 4c0fb1ed-ee5b-4036-a156-828a206cfc2e.
2016-09-27 20:19:32.868+0000 ERROR [o.n.b.v.r.i.ErrorReporter] Client
triggered an unexpected error [UnknownError]:
Property[1075,used=false,prev=-1,next=-1] not in use, reference
4c0fb1ed-ee5b-4036-a156-828a206cfc2e.
Property[1075,used=false,prev=-1,next=-1] not in use
org.neo4j.kernel.impl.store.InvalidRecordException:
Property[1075,used=false,prev=-1,next=-1] not in use
at
org.neo4j.kernel.impl.store.record.RecordLoad$1.verify(RecordLoad.java:55)
at
org.neo4j.kernel.impl.store.CommonAbstractStore.verifyAfterReading(CommonAbstractStore.java:1240)
at
org.neo4j.kernel.impl.store.CommonAbstractStore.readIntoRecord(CommonAbstractStore.java:1064)
at
org.neo4j.kernel.impl.store.CommonAbstractStore.getRecord(CommonAbstractStore.java:1042)
at org.neo4j.kernel.impl.transaction.state.Loaders$2.load(Loaders.java:165)
at org.neo4j.kernel.impl.transaction.state.Loaders$2.load(Loaders.java:145)
at
org.neo4j.kernel.impl.transaction.state.RecordChanges.getOrLoad(RecordChanges.java:72)
at
org.neo4j.kernel.impl.transaction.state.PropertyDeleter.deletePropertyChain(PropertyDeleter.java:45)
at
org.neo4j.kernel.impl.transaction.state.TransactionRecordState.getAndDeletePropertyChain(TransactionRecordState.java:336)
at
org.neo4j.kernel.impl.transaction.state.TransactionRecordState.nodeDelete(TransactionRecordState.java:322)
at
org.neo4j.kernel.impl.storageengine.impl.recordstorage.TransactionToRecordStateVisitor.visitDeletedNode(TransactionToRecordStateVisitor.java:89)
at
org.neo4j.storageengine.api.txstate.TxStateVisitor$Delegator.visitDeletedNode(TxStateVisitor.java:220)
at
org.neo4j.kernel.api.txstate.TransactionCountingStateVisitor.visitDeletedNode(TransactionCountingStateVisitor.java:100)
at org.neo4j.kernel.impl.api.state.TxState$12.visitRemoved(TxState.java:339)
at org.neo4j.kernel.impl.api.state.TxState$12.visitRemoved(TxState.java:335)
at
org.neo4j.kernel.impl.util.diffsets.SuperDiffSets.accept(SuperDiffSets.java:70)
at org.neo4j.kernel.impl.util.diffsets.DiffSets.accept(DiffSets.java:41)
at org.neo4j.kernel.impl.api.state.TxState.accept(TxState.java:274)
at
org.neo4j.kernel.impl.storageengine.impl.recordstorage.RecordStorageEngine.createCommands(RecordStorageEngine.java:304)
at
org.neo4j.kernel.impl.api.KernelTransactionImplementation.commit(KernelTransactionImplementation.java:431)
at
org.neo4j.kernel.impl.api.KernelTransactionImplementation.close(KernelTransactionImplementation.java:380)
at
org.neo4j.bolt.v1.runtime.internal.SessionStateMachine$State$3.commitTransaction(SessionStateMachine.java:187)
at
org.neo4j.bolt.v1.runtime.internal.SessionStateMachine$State$4.discardAll(SessionStateMachine.java:258)
at
org.neo4j.bolt.v1.runtime.internal.SessionStateMachine$State$4.pullAll(SessionStateMachine.java:237)
at
org.neo4j.bolt.v1.runtime.internal.SessionStateMachine.pullAll(SessionStateMachine.java:664)
at
org.neo4j.bolt.v1.runtime.internal.concurrent.SessionWorkerFacade.lambda$pullAll$4(SessionWorkerFacade.java:74)
at
org.neo4j.bolt.v1.runtime.internal.concurrent.SessionWorker.execute(SessionWorker.java:116)
at
org.neo4j.bolt.v1.runtime.internal.concurrent.SessionWorker.executeBatch(SessionWorker.java:102)
at
org.neo4j.bolt.v1.runtime.internal.concurrent.SessionWorker.run(SessionWorker.java:82)
at java.lang.Thread.run(Thread.java:745)
And error returned to client:
Structure {
signature: 127,
fields:
[ { code: 'Neo.DatabaseError.General.UnknownError',
message: 'An unexpected failure occurred, see details in the
database logs, reference number 4c0fb1ed-ee5b-4036-a156-828a206cfc2e.' } ] }
When I don't use tests that runs more sessions than connectionPoolSize and
without afterEach hook, then everything is OK.
So to summarize:
1) I hit NullPointerException in DB when running more sessions than
connectionPoolSize
2) After hitting NullPointerException, next test which is simple
transaction will timeout.
3) using afterEach hook that deletes all test nodes, sometimes I get
UnknownError on client and InvalidRecordException in DB
So how can I make sure that this sort of problems doesn't occur on my
server when requests will increase so much that there will be more sessions
than connectionPoolSize?
Thanks!
Michal
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