Multi DataSources: 1 RW + many RO

Question

We have an app with single database 'dbMain', with set of read and write operations.

Now we need to add using extra databases db1-db10 for read-only operations, for using in SomeServiceImpl.

The problem is:

• I need to use several DAO (for dbMain and db1) at SomeServiceImpl
• only single transactionManager can be defined at tx:annotation-driven and @Transactional will operate with it only.
• sometimes I got db-connection leaks at SomeServiceImpl for operations with db1DAO. At least in @PostConstruct init() {...}

Really, don't want to use JTA. What is the proper way to configure such environment?

<tx:annotation-driven transaction-manager="dbMainTransactionManager"/>

<bean id="dbMainSessionFactory"
     class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="dbMainDataSource"/>
...
</bean>
<bean id="dbMainTransactionManager"
      class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="dbMainSessionFactory"/>
...
</bean>

@Repository
public class DBMainDAOImpl extends HibernateDaoSupport implements DBMainDAO {
    @Resource(name = "dbMainSessionFactory")
    protected void init(SessionFactory sessionFactory) throws Exception {
        setSessionFactory(sessionFactory);
    }
...
}

@Transactional
@Service
public class SomeServiceImpl implements SomeService {
    @Autowired
    private DBMainDAO dbMainDAO;
...
}

Extra dbs:

<bean id="db1SessionFactory"
     class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="dataSource" ref="db1DataSource"/>
...
</bean>
<bean id="db1TransactionManager"
      class="org.springframework.orm.hibernate3.HibernateTransactionManager">
    <property name="sessionFactory" ref="db1SessionFactory"/>
...
</bean>

public class DB1DAOImpl extends HibernateDaoSupport implements DB1DAO {
    @Resource(name = "db1SessionFactory")
    protected void init(SessionFactory sessionFactory) throws Exception {
        setSessionFactory(sessionFactory);
    }
...
}

@Transactional
public class SomeServiceImpl implements SomeService {
    @Autowired
    private DBMainDAO dbMainDAO;
    @Autowired
    private DB1DAO db1DAO;
    ...
    @Autowired
    private DB10DAO db10DAO;

    @PostConstruct init() {
    ...
    }
...
}