spring-boo/neo4j Concurrent Save leads to deadlock

General Problem

I have a Node that has a Parent/Child relationship to itself (Same Label/Class). I can add a new Relathiship to a new Child node by adding the Parent Node to Parents-Relationship list (see code below). This works for saving one entity, when trying to Save the relationship for different Children of the same Parent I receive a deadlock-error (TransientDataAccessResourceException).

Setup

Maven Project

• Spring-Boot (spring-boot-starter-parent 2.6.13)
• Neo4J: spring-boot-starter-data-neo4j
• Project Lombok
• Java 11

Database: Docker-Container

docker run --name eval.neo4j -d -v eval.neo4j-data:/data -p 7474:7474 -p 7687:7687 neo4j

Config

spring:
  neo4j:
    uri: bolt://localhost:7687
    authentication:
      username: neo4j
      password: admin

Java Code

Node

@Getter
@Setter
@Node("Example")
@NoArgsConstructor
public class ExampleNode {

    private static final String CHILD_OF = "CHILD_OF";

    @Id
    @GeneratedValue
    private Long id;

    @Version
    private Long version;

    @Property
    private String name;

    @Relationship(type= CHILD_OF, direction = Relationship.Direction.OUTGOING)
    private Set<ExampleNode> parents;

    @Relationship(type= CHILD_OF, direction = Relationship.Direction.INCOMING)
    private Set<ExampleNode> children;

    public ExampleNode(String name) {
        this.name = name;
    }

    public void addParent(ExampleNode parent) {
        if (parents == null) {
            parents = new HashSet<>();
        }
        parents.add(parent);
    }

    @Override
    public String toString() {
        return "ExampleNode{" +
                "id=" + id +
                ", version=" + version +
                ", name='" + name + '\'' +
                ", parents=" + (parents == null ? 0: parents.size()) +
                ", children=" + (children == null ? 0 : children.size()) +
                '}';
    }
}

Repository:

@Transactional
public interface ExampleRepository extends CrudRepository<ExampleNode, Long> {
}

CRUD Service

@Slf4j
@Service
@RequiredArgsConstructor
public class ExampleService {

    private final ExampleRepository repository;

    @Transactional
    public Long create(String name, Long parentId) {
        ExampleNode entity = new ExampleNode(name);
        if (parentId != null) {
            entity.addParent(repository.findById(parentId).orElseThrow());
        }
        ExampleNode response = repository.save(entity);
        log.info("Created {}", response);
        return response.getId();
    }

    @Async
    public Future<Long> createAsync(String name, Long parentId) {
        return new AsyncResult<>(create(name, parentId));
    }

    public ExampleNode read(Long id) {
        return repository.findById(id).orElse(null);
    }

}

App with CommandLineRunner (for simplicity - the actual implementation uses RestController with spring-mvc

@Slf4j
@EnableAsync
@SpringBootApplication
public class ExampleApplication {

    public static void main(String[] args) {
        SpringApplication.run(ExampleApplication.class, args);
    }

    @Bean
    CommandLineRunner runner(ExampleService service) {
        return (args) -> {
            Long p1 = service.create("Parent-1", null);
            Long p2 = service.create("Parent-2", null);
           
            // works for synchronous calls or when synchronizing
            // before the first call. async is used to simulate
            // concurrent executions i.E. via rest-calls
            final Future<Long> one = service.createAsync("one", p1);
            final Future<Long> two = service.createAsync("two", p1);

            Long id1 = one.get(2, TimeUnit.SECONDS);
            Long id2 = two.get(2, TimeUnit.SECONDS);
            log.info("load parents {} {}", service.read(p1), service.read(p2));
            log.info("load children {}: {}, {}:{}", id1, service.read(id1), id2, service.read(id2));
        };
    }
}

Log

2022-12-07 08:42:07.537 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Getting transaction for [de.example.graph.service.ExampleService.create]
2022-12-07 08:42:07.550 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save]
2022-12-07 08:42:07.804 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save]
2022-12-07 08:42:07.805  INFO 27776 --- [           main] de.example.graph.service.ExampleService  : Created ProblemEntity{id=35, version=0, name='Parent-1', parents=0, children=0}
2022-12-07 08:42:07.807 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Completing transaction for [de.example.graph.service.ExampleService.create]
2022-12-07 08:42:07.835 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Getting transaction for [de.example.graph.service.ExampleService.create]
2022-12-07 08:42:07.836 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save]
2022-12-07 08:42:07.854 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save]
2022-12-07 08:42:07.854  INFO 27776 --- [           main] de.example.graph.service.ExampleService  : Created ProblemEntity{id=36, version=0, name='Parent-2', parents=0, children=0}
2022-12-07 08:42:07.854 TRACE 27776 --- [           main] o.s.t.i.TransactionInterceptor           : Completing transaction for [de.example.graph.service.ExampleService.create]
2022-12-07 08:42:07.882 TRACE 27776 --- [         task-1] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.findById]
2022-12-07 08:42:07.895 TRACE 27776 --- [         task-2] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.findById]
2022-12-07 08:42:08.211 TRACE 27776 --- [         task-2] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.findById]
2022-12-07 08:42:08.211 TRACE 27776 --- [         task-1] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.findById]
2022-12-07 08:42:08.223 TRACE 27776 --- [         task-1] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save]
2022-12-07 08:42:08.223 TRACE 27776 --- [         task-2] o.s.t.i.TransactionInterceptor           : Getting transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save]
2022-12-07 08:42:08.418 TRACE 27776 --- [         task-2] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save] after exception: org.springframework.dao.TransientDataAccessResourceException: ForsetiClient[transactionId=94, clientId=2] can't acquire ExclusiveLock{owner=ForsetiClient[transactionId=93, clientId=1]} on NODE_RELATIONSHIP_GROUP_DELETE(35), because holders of that lock are waiting for ForsetiClient[transactionId=94, clientId=2].
 Wait list:ExclusiveLock[
Client[93] waits for [ForsetiClient[transactionId=94, clientId=2]]]; Error code 'Neo.TransientError.Transaction.DeadlockDetected'; nested exception is org.neo4j.driver.exceptions.TransientException: ForsetiClient[transactionId=94, clientId=2] can't acquire ExclusiveLock{owner=ForsetiClient[transactionId=93, clientId=1]} on NODE_RELATIONSHIP_GROUP_DELETE(35), because holders of that lock are waiting for ForsetiClient[transactionId=94, clientId=2].
 Wait list:ExclusiveLock[
Client[93] waits for [ForsetiClient[transactionId=94, clientId=2]]]
2022-12-07 08:42:08.480 TRACE 27776 --- [         task-1] o.s.t.i.TransactionInterceptor           : Completing transaction for [org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save]
2022-12-07 08:42:08.495  INFO 27776 --- [         task-1] de.example.graph.service.ExampleService  : Created ProblemEntity{id=37, version=0, name='one', parents=1, children=0}
2022-12-07 08:42:08.498  INFO 27776 --- [           main] ConditionEvaluationReportLoggingListener : 

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.
2022-12-07 08:42:08.537 ERROR 27776 --- [           main] o.s.boot.SpringApplication               : Application run failed

java.lang.IllegalStateException: Failed to execute CommandLineRunner
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:785) ~[spring-boot-2.6.13.jar:2.6.13]
    at org.springframework.boot.SpringApplication.callRunners(SpringApplication.java:766) ~[spring-boot-2.6.13.jar:2.6.13]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:314) ~[spring-boot-2.6.13.jar:2.6.13]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1317) ~[spring-boot-2.6.13.jar:2.6.13]
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1306) ~[spring-boot-2.6.13.jar:2.6.13]
    at de.example.graph.ExampleApplication.main(ExampleApplication.java:20) ~[classes/:na]
Caused by: java.util.concurrent.ExecutionException: org.springframework.dao.TransientDataAccessResourceException: ForsetiClient[transactionId=94, clientId=2] can't acquire ExclusiveLock{owner=ForsetiClient[transactionId=93, clientId=1]} on NODE_RELATIONSHIP_GROUP_DELETE(35), because holders of that lock are waiting for ForsetiClient[transactionId=94, clientId=2].
 Wait list:ExclusiveLock[
Client[93] waits for [ForsetiClient[transactionId=94, clientId=2]]]; Error code 'Neo.TransientError.Transaction.DeadlockDetected'; nested exception is org.neo4j.driver.exceptions.TransientException: ForsetiClient[transactionId=94, clientId=2] can't acquire ExclusiveLock{owner=ForsetiClient[transactionId=93, clientId=1]} on NODE_RELATIONSHIP_GROUP_DELETE(35), because holders of that lock are waiting for ForsetiClient[transactionId=94, clientId=2].
 Wait list:ExclusiveLock[
Client[93] waits for [ForsetiClient[transactionId=94, clientId=2]]]
    at java.base/java.util.concurrent.FutureTask.report(FutureTask.java:122) ~[na:na]
    at java.base/java.util.concurrent.FutureTask.get(FutureTask.java:205) ~[na:na]
    at de.example.graph.ExampleApplication.lambda$runner$0(ExampleApplication.java:33) ~[classes/:na]
    at org.springframework.boot.SpringApplication.callRunner(SpringApplication.java:782) ~[spring-boot-2.6.13.jar:2.6.13]
    ... 5 common frames omitted
Caused by: org.springframework.dao.TransientDataAccessResourceException: ForsetiClient[transactionId=94, clientId=2] can't acquire ExclusiveLock{owner=ForsetiClient[transactionId=93, clientId=1]} on NODE_RELATIONSHIP_GROUP_DELETE(35), because holders of that lock are waiting for ForsetiClient[transactionId=94, clientId=2].
 Wait list:ExclusiveLock[
Client[93] waits for [ForsetiClient[transactionId=94, clientId=2]]]; Error code 'Neo.TransientError.Transaction.DeadlockDetected'; nested exception is org.neo4j.driver.exceptions.TransientException: ForsetiClient[transactionId=94, clientId=2] can't acquire ExclusiveLock{owner=ForsetiClient[transactionId=93, clientId=1]} on NODE_RELATIONSHIP_GROUP_DELETE(35), because holders of that lock are waiting for ForsetiClient[transactionId=94, clientId=2].
 Wait list:ExclusiveLock[
Client[93] waits for [ForsetiClient[transactionId=94, clientId=2]]]
    at org.springframework.data.neo4j.core.Neo4jPersistenceExceptionTranslator.translateImpl(Neo4jPersistenceExceptionTranslator.java:107) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.Neo4jPersistenceExceptionTranslator.translateExceptionIfPossible(Neo4jPersistenceExceptionTranslator.java:79) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.DefaultNeo4jClient.potentiallyConvertRuntimeException(DefaultNeo4jClient.java:233) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.DefaultNeo4jClient.access$600(DefaultNeo4jClient.java:62) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.DefaultNeo4jClient$DefaultRecordFetchSpec.one(DefaultNeo4jClient.java:461) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.Neo4jTemplate.lambda$processNestedRelations$25(Neo4jTemplate.java:865) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.mapping.model.BasicPersistentEntity.doWithAssociations(BasicPersistentEntity.java:388) ~[spring-dat开发者_Python百科a-commons-2.6.9.jar:2.6.9]
    at org.springframework.data.neo4j.core.Neo4jTemplate.processNestedRelations(Neo4jTemplate.java:729) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.Neo4jTemplate.processRelations(Neo4jTemplate.java:714) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.Neo4jTemplate.saveImpl(Neo4jTemplate.java:433) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.core.Neo4jTemplate.save(Neo4jTemplate.java:345) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at org.springframework.data.neo4j.repository.support.SimpleNeo4jRepository.save(SimpleNeo4jRepository.java:119) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:na]
    at java.base/jdk.internal.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:na]
    at java.base/jdk.internal.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:na]
    at java.base/java.lang.reflect.Method.invoke(Method.java:566) ~[na:na]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker$RepositoryFragmentMethodInvoker.lambda$new$0(RepositoryMethodInvoker.java:289) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker.doInvoke(RepositoryMethodInvoker.java:137) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.data.repository.core.support.RepositoryMethodInvoker.invoke(RepositoryMethodInvoker.java:121) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.data.repository.core.support.RepositoryComposition$RepositoryFragments.invoke(RepositoryComposition.java:530) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.data.repository.core.support.RepositoryComposition.invoke(RepositoryComposition.java:286) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.data.repository.core.support.RepositoryFactorySupport$ImplementationMethodExecutionInterceptor.invoke(RepositoryFactorySupport.java:640) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.doInvoke(QueryExecutorMethodInterceptor.java:164) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.data.repository.core.support.QueryExecutorMethodInterceptor.invoke(QueryExecutorMethodInterceptor.java:139) ~[spring-data-commons-2.6.9.jar:2.6.9]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.transaction.interceptor.TransactionInterceptor$1.proceedWithInvocation(TransactionInterceptor.java:123) ~[spring-tx-5.3.23.jar:5.3.23]
    at org.springframework.transaction.interceptor.TransactionAspectSupport.invokeWithinTransaction(TransactionAspectSupport.java:388) ~[spring-tx-5.3.23.jar:5.3.23]
    at org.springframework.transaction.interceptor.TransactionInterceptor.invoke(TransactionInterceptor.java:119) ~[spring-tx-5.3.23.jar:5.3.23]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.dao.support.PersistenceExceptionTranslationInterceptor.invoke(PersistenceExceptionTranslationInterceptor.java:137) ~[spring-tx-5.3.23.jar:5.3.23]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.aop.interceptor.ExposeInvocationInterceptor.invoke(ExposeInvocationInterceptor.java:97) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:186) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.aop.framework.JdkDynamicAopProxy.invoke(JdkDynamicAopProxy.java:215) ~[spring-aop-5.3.23.jar:5.3.23]
    at com.sun.proxy.$Proxy64.save(Unknown Source) ~[na:na]
    at de.example.graph.service.ExampleService.create(ExampleService.java:27) ~[classes/:na]
    at de.example.graph.service.ExampleService.createAsync(ExampleService.java:34) ~[classes/:na]
    at de.example.graph.service.ExampleService$$FastClassBySpringCGLIB$$91503e55.invoke(<generated>) ~[classes/:na]
    at org.springframework.cglib.proxy.MethodProxy.invoke(MethodProxy.java:218) ~[spring-core-5.3.23.jar:5.3.23]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.invokeJoinpoint(CglibAopProxy.java:793) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.aop.framework.ReflectiveMethodInvocation.proceed(ReflectiveMethodInvocation.java:163) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.aop.framework.CglibAopProxy$CglibMethodInvocation.proceed(CglibAopProxy.java:763) ~[spring-aop-5.3.23.jar:5.3.23]
    at org.springframework.aop.interceptor.AsyncExecutionInterceptor.lambda$invoke$0(AsyncExecutionInterceptor.java:115) ~[spring-aop-5.3.23.jar:5.3.23]
    at java.base/java.util.concurrent.FutureTask.run(FutureTask.java:264) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1128) ~[na:na]
    at java.base/java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:628) ~[na:na]
    at java.base/java.lang.Thread.run(Thread.java:839) ~[na:na]
Caused by: org.neo4j.driver.exceptions.TransientException: ForsetiClient[transactionId=94, clientId=2] can't acquire ExclusiveLock{owner=ForsetiClient[transactionId=93, clientId=1]} on NODE_RELATIONSHIP_GROUP_DELETE(35), because holders of that lock are waiting for ForsetiClient[transactionId=94, clientId=2].
 Wait list:ExclusiveLock[
Client[93] waits for [ForsetiClient[transactionId=94, clientId=2]]]
    at org.neo4j.driver.internal.util.Futures.blockingGet(Futures.java:111) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
    at org.neo4j.driver.internal.InternalResult.blockingGet(InternalResult.java:107) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
    at org.neo4j.driver.internal.InternalResult.hasNext(InternalResult.java:53) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
    at org.springframework.data.neo4j.core.DefaultNeo4jClient$DefaultRecordFetchSpec.one(DefaultNeo4jClient.java:455) ~[spring-data-neo4j-6.2.9.jar:6.2.9]
    ... 43 common frames omitted
    Suppressed: org.neo4j.driver.internal.util.ErrorUtil$InternalExceptionCause: null
        at org.neo4j.driver.internal.util.ErrorUtil.newNeo4jError(ErrorUtil.java:80) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.async.inbound.InboundMessageDispatcher.handleFailureMessage(InboundMessageDispatcher.java:107) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.messaging.common.CommonMessageReader.unpackFailureMessage(CommonMessageReader.java:75) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.messaging.common.CommonMessageReader.read(CommonMessageReader.java:53) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.async.inbound.InboundMessageHandler.channelRead0(InboundMessageHandler.java:81) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.async.inbound.InboundMessageHandler.channelRead0(InboundMessageHandler.java:37) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.SimpleChannelInboundHandler.channelRead(SimpleChannelInboundHandler.java:99) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:327) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:299) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.async.inbound.MessageDecoder.channelRead(MessageDecoder.java:42) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:327) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.handler.codec.ByteToMessageDecoder.channelRead(ByteToMessageDecoder.java:299) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.handler.timeout.IdleStateHandler.channelRead(IdleStateHandler.java:286) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:357) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.DefaultChannelPipeline$HeadContext.channelRead(DefaultChannelPipeline.java:1410) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:379) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:365) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.DefaultChannelPipeline.fireChannelRead(DefaultChannelPipeline.java:919) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.AbstractNioByteChannel$NioByteUnsafe.read(AbstractNioByteChannel.java:166) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKey(NioEventLoop.java:722) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeysOptimized(NioEventLoop.java:658) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.processSelectedKeys(NioEventLoop.java:584) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:496) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:997) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        at org.neo4j.driver.internal.shaded.io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30) ~[neo4j-java-driver-4.4.9.jar:4.4.9-e855bcc800deff6ddcf064c822314bb5c8d08c53]
        ... 1 common frames omitted

2022-12-07 08:42:08.543  INFO 27776 --- [           main] o.neo4j.driver.internal.InternalDriver   : Closing driver instance -634758184
2022-12-07 08:42:08.548  INFO 27776 --- [           main] o.n.d.i.async.pool.ConnectionPoolImpl    : Closing connection pool towards localhost:7687

Process finished with exit code 1

Problem

Saving the second Child node seems to be locked by the first (or the other way around). I thought this would be resolved by the transaction annotation. I am also worried about NODE_RELATIONSHIP_GROUP_DELETE in the log-output - this seems to indicate that the first child will be removed when saving the second. I was unable to find a simple spring-like solution for only saving the node and the relationship without touching the parent-node, since the parent node properties are unchanged.

Thank you for your Help :)