Use Query Caching

Query caching uses the L2 cache to store queries so that whenever the same query needs to be executed again, it can be fetched from the cache. Please note that any object retrieved as a result of the query is cached to their respective regions. Therefore, mark objects as cacheable for efficient use of query caching. However, the query and the result set primary keys are stored in a default query region called "org.hibernate.cache.StandardQueryCache", which is a fully qualified name of Hibernate's StandardQueryCache class.

Note

Since not every query's results remain the same for a period of time, therefore use query caching with queries whose results are less likely to change frequently.

To enable query caching, add the following tag to your configuration in hibernate.cfg.xml.

<hibernate-configuration>
  <session-factory>
  <property name="hibernate.cache.use_second_level_cache">true</property>
  <property name="hibernate.cache.region.factory_class">JCacheRegionFactory</property>
  <property name="ncache.application_id">myapp</property>
  <property name="hibernate.cache.use_query_cache">true</property>
  </session-factory>
</hibernate-configuration>

Enabling the query cache does not cache each query by default. Instead queries that require to be cached are to be set as cacheable in the code. To set a query as cacheable, call setCacheable(true) function of query while creating a query.The code below is an example showing a cacheable query:

try
{
    List customerEnumerator = session.createQuery("from Customer c").setCacheable(true).list(); 
    List customers = new ArrayList();
    Transaction tx = null;
    if (!session.isConnected())
    {
        session = factory.openSession();
    }
    tx = session.beginTransaction();
    for (Customer customer : (List<Customer>) customerEnumerator)
    {
        customers.add(customer);
    }
    tx.commit();
}
catch (Exception ex)
{
    tx.rollback();
    session.clear();
    session.disconnect();
    throw ex;
}

Use Query Caching

Note

See Also