Transaction management not working in neo4j-omg when using SessionFactory

I wrote a small Spring Boot application that uses spring-boot-starter-data-neo4j to connect to a Neo4j instance.

I'd like to execute some updates through Cypher queries, but can't get transaction management to work when opening a Session using the SessionFactory. Transaction management works fine using OGM annotated entities through a Neo4jRepository.

For testing purposes, I wrote two simple services annotated with @Transactional:

Using OGM annotated class and a Neo4jRepository:

@Service
@Transactional
public class OgmServiceImpl implements OgmService {
    private final PersonRepository personRepository;

    public OgmServiceImpl(PersonRepository personRepository) {
        this.personRepository = personRepository;
    }

    @Override
    public void storeData() {
        personRepository.save(new Person("Jack"));
        if (true) {
            throw new IllegalStateException();
        }
        personRepository.save(new Person("Jill"));
    }
}

When executing the storeData() method, neither Jack nor Jill is saved to Neo4j. Works as expected.

The other service does the same by executing Cypher queries on the Neo4j Session:

@Service
@Transactional
public class CypherServiceImpl implements CypherService {
    private final SessionFactory sessionFactory;

    public CypherServiceImpl(SessionFactory sessionFactory) {
        this.sessionFactory = sessionFactory;
    }

    @Override
    public void storeData() {
        Session session = sessionFactory.openSession();
        session.query("CREATE (p:Person { name: 'Jack' })", Map.of());
        if (true) {
            throw new IllegalStateException();
        }
        session.query("CREATE (p:Person { name: 'Jill'})", Map.of());
    }
}

However, transaction management fails, as Jack is stored in Neo4j.

To me, this behavior is quite unexpected. I can get transaction management to work by explicitly starting a transaction, but that is not the way I like it to be:

    public void storeData() {
        Session session = sessionFactory.openSession();
        try (Transaction tx = session.beginTransaction()) {
            session.query("CREATE (p:Person { name: 'Jack' })", Map.of());
            if (true) {
                throw new IllegalStateException();
            }
            session.query("CREATE (p:Person { name: 'Jill'})", Map.of());
            tx.commit();
        }
    }

Do I need to configure the SessionFactory myself to get this to work? Why doesn't Spring Boot take care of this?

Just looked at the docs. According to the docs when you programatically call SessionFactory#openSession a completely new session is created which isn't necessarily in the transaction scope specified with the @Transactional annotation.

To further ensure this you can try checking for an assertion error with this code:

@Override
public void storeData() {
    Session session = sessionFactory.openSession();
    assert session.getTransaction() != null;

    session.query("CREATE (p:Person { name: 'Jack' })", Map.of());       
    session.query("CREATE (p:Person { name: 'Jill'})", Map.of());
} 

This should result in an assertion error. Unlike hibernate which provides a way of getting the current session I couldn't find neo4J-ogm way to do it though.

The code written below works because even though you are creating a completely new Session is created the transaction is managed by you. Here you are creating a self managed transaction, not the Spring container managed transaction, although it is generally not a good idea.

public void storeData() {
    Session session = sessionFactory.openSession();
    try (Transaction tx = session.beginTransaction()) {
        session.query("CREATE (p:Person { name: 'Jack' })", Map.of());
        if (true) {
            throw new IllegalStateException();
        }
        session.query("CREATE (p:Person { name: 'Jill'})", Map.of());
        tx.commit();
    }
}