Hibernate Query Cache

[ying lam]

Hi,

I try to setup Hibernate Query Cache, I am using ehcache.

It works in the beginning (i.e. if i execute the same query multiple times,
it does not send the sql commands to mysql everytime).

however, after about 1 minutes, the cache seems expire (i.e. I see hibernate executes sql commmands to the database.


I have the following configuration in my ehcache.xml file. So the query cache should last 2 hours (7200 seconds), I don't understand why my query cache expires so soon.

Thank you for any help.

<defaultCache maxElementsInMemory="10000" eternal="false" overflowToDisk="true" timeToIdleSeconds="7200" timeToLiveSeconds="7200" diskPersistent="false" diskExpiryThreadIntervalSeconds="7200"/>

[pascal betz]

- show the code where you create the query
- are there more different queries than the cache size ?

pascal

[Paul Sturrock]

If we are talking about the Query Cache, do the parameters of your query change? This will mean the cache needs rebuilt.

However, you mention ehcache, which suggests this might be about Second Level caching, which is nothing to do with Query Caching. In which case, you might want to check that your cache has not become full.

[ying lam]

Thanks for the help.

Session session = HibernateUtil.getSessionFactory().getCurrentSession();
 
session.beginTransaction();
 
// use the make to store the deviceCode
Query query = session
.createQuery("from User as user where  user.language= :language and user.address.zipcode = :zipcode");
 
query.setString("language", language).setString("zipcode", zipcode);

 
query.setCacheable(true);
 
List result = query.list();
 
session.getTransaction().commit();

No, I am pretty sure that the query only return 1 result.
And I am sure that the query parameters are the same everything i execute the query because I just reloading the same page again and again (which trigger the query with parameters).

I appreciate if anyone can give me some ideas to my problem.

[kri shan]

you need to set the hibernate.cache.use_query_cache property in the hibernate.cfg.xml file to true, as follows:

<property name="hibernate.cache.use_query_cache">true</property>

Then, you use the setCacheable() method.

http://www.devx.com/dbzone/Article/29685/1954?pf=true refer this link.

QueryCaching is diffferent from the second level caching.