Second level cache does not work

[Alex Bokov]

Hi,
I am trying to make work hibernate second level caching not successfully.

I have:

    
...
@Entity
@Table(name="CATEGORY")
@Cache(usage = CacheConcurrencyStrategy.READ_ONLY)
public class Category {

	private Integer id;
	private String name;

    @Id
    @Column(name = "ID")
	public Integer getId() {
		return id;
	}
	public void setId(Integer id) {
		this.id = id;
	}

    @Column(name = "NAME")
 	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}

}

persistence.xml

   

<persistence xmlns="http://java.sun.com/xml/ns/persistence"
    xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
    xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd"
    version="1.0">
    <persistence-unit name="punit">
    
    <properties>
    	<property name="hibernate.cache.provider_class" value="com.opensymphony.oscache.hibernate.OSCacheProvider" />
    	<property name="hibernate.cache.use_second_level_cache" value="true" />
    	<property name="hibernate.cache.use_query_cache" value="true" />
    </properties>
    
    
    </persistence-unit>
</persistence>

CategoryServiceImpl.java

  
...
	@SuppressWarnings("unchecked")
	public List<Category> findAll(){
		
        Query query = getEntityManager().createQuery("select c FROM Category c");
        return query.getResultList();
	}
...

and every time I call findAll() in CategoryService it calls data base, at least I see query log.

Is there some thing that I missed?
How to get caching work?

Thanks for any help.

[Paul Sturrock]

Only certain method hit the cache. From the documentation:

Whenever you pass an object to save(), update() or saveOrUpdate() and whenever you retrieve an object using load(), get(), list(), iterate() or scroll(), that object is added to the internal cache of the Session.

[Alex Bokov]

I found that caching works for single element

with session factory:

  return (Category)hibernateSession.get(Category.class, id);  

and with entity manager:

  return getEntityManager().find(Category.class, id);  

but does not work for lists

with session factory:

Criteria hibernateCriteria = hibernateSession.createCriteria(Category.class);	
return hibernateCriteria.list();   

and entity manager:

Query query = getEntityManager().createQuery("select c FROM Category c");
return query.getResultList();  

[Mark Spritzler]

Read Paul's post again.

Anytime you run a query whether from Criteria, HQL, or SQL Hibernate will NOT get data from the second level cache.

But if you turn on the second level query cache, then some queries can go to the query cache. In the query cache only IDs are stored. And there is a requirement that the Objects those IDs represent must be in the standard second level cache in a cache region.

One issue you have with the query cache is that the resultset could get stale real quickly if data is inserted or deleted from the database.

Mark

[Alex Bokov]

query caching is working

but hibernate need to be kicked

with session factory

			Query query = hibernateSession.createQuery("select c FROM Category c");
			query.setCacheable(true);
			allCategories = query.list();    

with entity manager

 return getEntityManager().createQuery("select c FROM Category c").setHint("org.hibernate.cacheable", true).getResultList();