Grails upgrade from 2 to 4 ,unable to fetch data from DB

Question

i am upgrading my grails 2 app to grails 4. versions are

Hibernate 5 , Grails 4.0.10 , JVM 8

my problem is i am unable to fetch data from db by using User.findByName(....) or any other findBy or get() . it always says org.springframework.dao.DataAccessResourceFailureException: Could not obtain current Hibernate Session; nested exception is org.hibernate.HibernateException: No Session found for current thread at org.grails.orm.hibernate.GrailsHibernateTemplate.getSession(GrailsHibernateTemplate.java:335)

my hibernate config has

> hibernate :
>     cache:
>       use_second_level_cache : true
>       use_query_cache : true
>       provider_class : "net.sf.ehcache.hibernate.EhCacheProvider"
>       region:
>         factory_class : 'org.hibernate.cache.ehcache.SingletonEhCacheRegionFactory'


>      format_sql : false
>      generate_statistics : false
> 
>     allow_update_outside_transaction: true

if I use @Transactional to the method ,then i'm able to fetch the data otherwise it fails.

is there any other way to fetch the data like in previous versions?