Java 在Springboot中，当我使用EntityManager合并方法时，服务记录并没有提交到数据库中

这是我的db数据源配置类（我在几个数据库上有连接，所以我有自定义的db配置）

因此，paymentData被存储。我可以在输出中看到结果，但它并没有提交，数据库中也并没有记录。Select语句运行良好，因为它不需要提交。我知道存在一些事务和自动提交问题，但我找不到正确的方法来启用自动提交或手动处理事务

@Configuration
@EnableTransactionManagement
@EnableJpaRepositories(basePackages = "com.test.package_name", entityManagerFactoryRef = "entityManager", transactionManagerRef = "transactionManager")
public class DBConfiguration {
    @Bean(name = "dataSource")
    @Primary
    @ConfigurationProperties(prefix = "spring.datasource")
    public DataSource ojdbcDataSource() {
        return DataSourceBuilder.create().build();
    }

    @PersistenceContext(unitName = "db")
    @Primary
    @Bean(name = "entityManager")
    public LocalContainerEntityManagerFactoryBean ojdbcEntityManagerFactory(EntityManagerFactoryBuilder builder) {
        return builder.dataSource(ojdbcDataSource()).persistenceUnit("db").properties(jpaProperties())
                .packages("com.test.package_name").build();
    }

    @Bean(name = "transactionManager")
    public PlatformTransactionManager transactionManager(EntityManagerFactoryBuilder builder) {
        JpaTransactionManager tm = new JpaTransactionManager();
        tm.setEntityManagerFactory(ojdbcEntityManagerFactory(builder).getObject());
        tm.setDataSource(ojdbcDataSource());
        return tm;
    }

    private Map<String, Object> jpaProperties() {
        Map<String, Object> props = new HashMap<>();
        props.put("hibernate.physical_naming_strategy", SpringPhysicalNamingStrategy.class.getName());
        props.put("hibernate.implicit_naming_strategy", SpringImplicitNamingStrategy.class.getName());
        return props;
    }
}

@Service
class SomeClass{
    @PersistenceContext(unitName = "db", type = PersistenceContextType.EXTENDED)
    private EntityManager em;
        
    @Transactional
    protected void savePaymentData(PaymentInput input) {
        PaymentData paymentData = new PaymentData();
        paymentData.setVar1("test1");
        paymentData.setVar2("test2");

        paymentData = em.merge(paymentData);
        System.out.println(paymentData);
    }
}