@Transactional(Transactional.TxType.SUPPORTS) and access propertie with @ManyToOne(fetch = FetchType.LAZY)

[danieltche]

Hi everyone.
I have the class below:

@ApplicationScoped
@Slf4j
@Transactional(Transactional.TxType.SUPPORTS)
public class ConsultarImovelService {

    @Inject
    ImovelRepository repository;

    @Inject
    ImovelMapper mapper;
    
    /*
     * Consulta um imovel pelo seu ID.
     */
    public ImovelDto executa(Long id) {
        log.info("Consultando imovel: " + id);

        var imovel = repository.findByIdOptional(id);
        return imovel.map(nullable -> mapper.toModel(nullable))
                .orElseThrow(() -> new NotFoundException("imovel não encontrado"));
    }
}

The Entity returned by repository.findByIdOptional(id); has a "@manytoone(fetch = FetchType.LAZY)" relationship to another entity.
After calling the method "repository.findByIdOptional(id)", there is no database connection open ( agroal_active_count=0 ). But after calling " mapper.toModel()", a database connection is opened (agroal_active_count = 1.0) and it remains open..
What is the best solution in this case? Should I change the transaction type to REQUIRED, or should I re-implement the findByIdOptional method with a join?
Another question: is it possible set some property so that an error is throw when I try to access a LAZY relationship outside a transaction? I worked with Jboss 7.4 and in that case the getter of a property with LAZY would return null.