Second level cache question

shendel18 · **Joined:** Wed Aug 26, 2009 3:29 am **Posts:** 5

Hello, i am working with hibernate second level cache. I have already configure and activate it.. But im not statisfied that it is fully working.Based on my research and what i've read on the sample in net. After the object is loaded to cache, it will cut 50-70 percent on its loading time..In my program i'm getting almost the same loading time (in miliseconds) every time i called a process which load the same object. How can i assure that my second-level cache is fully working.. Can anyone help me?

Here is the log in my tomcat:

[http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1830819
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1839827
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1842521
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1848512
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1852080
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1866928
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1873554
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1874178
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1877083
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1878320
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1883315
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1887246
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1889448
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1899559
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1903456
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1911216
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1917414
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1919508
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1933371
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1933393
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1938679
> [http-80-1] ReadOnlyCache.put(58) | Caching:
> com.company.project.model.GroupProduct#1943884

sanne.grinovero · **Posted:** Tue Oct 13, 2009 3:47 am

to know if it's working you should try reloading the same object twice: verify the first time you hit the database and the second time you hit the cache. From your log it appears you're working on a different entity each time.

shendel18 · **Joined:** Wed Aug 26, 2009 3:29 am **Posts:** 5

Thanks grinovero for the suggestion. You are right based on the my logs in loads different entity of GroupProduct. I assume that those in entity is now my cache after first attempt. To make it clearer, i have called a function that loads list of GroupProduct entity. In my second attempt in loading same list. I have same result of loading time compared to my first load. That is what i've been wondering all this time.

Here is what im doing in DAOHibernate in determining the loading time:

Code:

    public List<GroupProduct> findByServiceId(String serviceId) {
       Long serviceIdLong = Long.valueOf(serviceId);
       List<GroupProduct> gpDTOList = new ArrayList<GroupProduct>();

       long a = System.currentTimeMillis();
   log.debug("start time -  DAO: " + a);

GroupProduct as gp where version=0 and serviceID=?", serviceIdLong);
        
      gpDTOList = getHibernateTemplate().find("from GroupProduct gp where gp.version=0 and gp.serviceID=" +  serviceIdLong);
      
        
       long b = System.currentTimeMillis();
   log.debug("Execution time - DAO: " + (b - a) + " ms");
      
       return gpDTOList;
    }

Here is the log:

First load: 3983 ms
Second load: 3582 ms
Third load : 3402 ms

I'm having same loading time. Even same entity is called. Weird. Please help..

shendel18 · **Joined:** Wed Aug 26, 2009 3:29 am **Posts:** 5

DEBUG [main] CacheFactory.createCache(39) | instantiating cache region: com.company.project.model.
GroupProduct usage strategy: read-only
WARN [main] CacheFactory.createCache(43) | read-only cache configured for mutable class: com.company
.project.model.GroupProduct

Do i need to add @mutable annotation to be object? above is the logs in my tomcat.. I still Didn't find any solution or
clear explanation about what might be the cause, why it is still loading same duration as first load. Although the logs shows my entity is being cache it has no effect in loading speed after first load. Any help?

GroupProduct class:

Code:

@Entity @Table(name="group_product")
@Cache(usage = CacheConcurrencyStrategy.READ_ONLY)
public class GroupProduct extends BaseObject {
    private Long id;
    .... 
    ....

sanne.grinovero · **Posted:** Fri Oct 16, 2009 7:59 am

Quote:

Do i need to add @mutable annotation to be object?

No, it's the other way around: your entities are mutable, it's the cache which needs to be declared read-write but is read-only.

About your previous question, Hibernate is very careful in not enabling caches if you're not really sure and aware of the subtle consequences. So enabling caching for a single-object load requires:
* to enable the second level cache globally (and configure it)
* to enable caching on the entity

Both need to be true, or it won't use it.

To cache queries you have to go beyond that:
* enable query caching globally
* specify on the query that it's cachable

Even more, when you change any object which might affect the query result, the results are evicted from cache.
Example:
1) list all users --> need to load from database
2) lists all users --> will use cache
3) insert a new user -->invalidates the query cache for "list all users" query
4) lists all users --> needs to query the database again

This is all needed to have transactions work correctly, and use caches.
Hope this is useful to verify your cache usage: be sure to enable all options and to not invalidate the entry.