Hibernate JPA Caching

Question

I have a table named Master_Info_tbl. Its a lookup table:

Here is the code for the table:

 @Entity
@Table(name="MASTER_INFO_T")
 public class CodeValue  implements java.io.Serializable {
 private static final long serialVersionUID = -3732397626260983394L;
 private Integer objectid;
 private String codetype;
 private String code;
 private String shortdesc;
 private String longdesc;
 private Integer dptid;
 private Integer sequen;
 private Timestamp begindate;
 private Timestamp enddate;
 private String username;
 private Timestamp rowlastchange;
 //getter Setter methods

I have a service layer which calls the method

service.findbycodeType("Code1");

same way this table is queried for the other code types as well e.g. code2, code3 and so on till code10 which gets the result set from the same table and is shown into the drop down of the jsp pages since these drop downs are in 90% of the pages I am thinking to cache them globally.

Any idea how to achieve this?

FYI: I am using JPA and Hibernate with Struts2 and Spring. The database being used is DB2 UDB8.2

@Pascal
Thank you very much for all your responses. It has helped me a lot.I implemented everything what I supposed to implement(I Think). Still I dont know if the second level caching is working or not.Since I am not able to see anything in the logging in the log4j logging file from cache and also nothing is showing up in the console. In order to show that second level cache implementation is working I need to have some kind of proof and need to show it to my manager.So I am kind of stuck.
Please help!
I know I am very close to finish it up but just....
Here is my code(if you think something is missing or something should not be there please do let me know):
Entity Class

@Entity
@Cache(usage=CacheConcurrencyStrategy.NONSTRICT_READ_WRITE)
@Table(name = "CODEVALUE_T")
public class CodeValue implements java.io.Serializable {
//all the field name with getter and setter
}

Persistence.xml:

<properties>
            <property name="hibernate.dialect" value="org.hibernate.dialect.DB2Dialect" />
            <property name="hibernate.show_sql" value="false" />
            <property name="hibernate.cache.use_second_level_cache" value="true"/>
            <property name="hibernate.cache.use_query_cache" value="true"/>
            <property name="hibernate.cache.provider_class" value="org.hibernate.cache.EhCacheProvider" />
        </properties>

Service Layer DAO:

try {
            System.out.println("Calling the findByCodetype() method");
            final String queryString = "select model from CodeValue model where model.codetype"
                    + "= :propertyValue" + " order by model.code";

            Query query = em.createQuery(queryString);
            query.setHint("org.hibernate.cacheable", true);
            query.setParameter("propertyValue", propertyName);
            return query.getResultList();

        } catch (RuntimeException re) {
            logger.error("findByCodetype failed: ", re);
            throw re;
        }

Log4j.property value to show the verbose
log4j.category.org.hibernate.cache=DEBUG

ehcache.xml code(It's location is in src/ folder same place where my struts.xml file is located)

<ehcache>
   <diskStore path="java.io.tmpdir"/>
   <defaultCache
        maxElementsInMemory="10000"
        eternal="false"
        timeToIdleSeconds="6000"
        timeToLiveSeconds="12000"
        overflowToDisk="true"
        diskPersistent="false"
        diskExpiryThreadIntervalSeconds="120"
        />

</ehcache>

Pascal Thivent · Accepted Answer · 2010-05-21 01:11:23Z

13

(...) since these drop downs are in 90% of the pages I am thinking to cache them globally.

Using the query cache would be very appropriate for this use case. So activate the second-level cache, cache the CodeValue entity (see 2.2.8. Caching entities) and put the query behind findbycodeType in the query cache. To do so, use:

javax.persistence.Query query = manager.createQuery(...);
query.setHint("org.hibernate.cacheable", true);

And to clarify, the combination of the query and the values provided as parameters to that query is used as a key, and the value is the list of identifiers for that query. Schematically, something like that:

*--------------------------------------------------------------------------*
|                              Query Cache                                 |
|--------------------------------------------------------------------------|
| [ "from CodeValue c where c.codetype=?", ["Code1"] ] -> [ 1, 2, ... ]    |
| [ "from CodeValue c where c.codetype=?", ["Code2"] ] -> [ 3, 5, 6, ... ] |
*--------------------------------------------------------------------------*

So calling your method with different arguments won't "flush previous data", the argument is part of the key (or the query cache wouldn't work).

Note that this is Hibernate specific, JPA 1.0 doesn't specify second-level cache and query caching.

5 Comments

Sameer Malhotra Over a year ago

As I mentioned I am using jpa with hibernate and for some reason when I try to set em.setCacheable(true); i am not able to do it. This is the entitymanger code: import javax.persistence.EntityManager; @PersistenceContext public void setEntityManager(EntityManager em) { this.em = em; } Is there any jar file I am missing?

Sameer Malhotra Over a year ago

I got another solution as follows: if (query instanceof org.hibernate.ejb.QueryImpl) { logger .info("Yes the query is of the instance org.hibernate.ejb.QueryImpl so alreaedy set the cacheable true"); ((org.hibernate.ejb.QueryImpl) query).getHibernateQuery() .setCacheable(true); } do u think it might work...

Sameer Malhotra Over a year ago

@Pascal Thankyou very much for the update. I have implemented the 2nd level cache. now How do I know that the caching is working properly. I meant to say I just want to make sure that the object which I am marking as cacheable are there in the cache somewhere?

Pascal Thivent Over a year ago

@Sameer Configure Hibernate to Log all second-level cache activity. See this answer

Sameer Malhotra Over a year ago

@Pascal Please look into the new Answer I have posted and if you have any suggestion on it.

robert · Accepted Answer · 2012-06-03 15:01:43Z

6

Hibernate sadly logs the sql statements to the console even if the hit comes from the cache.

Wrong, Hibernate doesn't log sql statements if the cache has been used, confirmed with the following config:

persistence.xml:

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

Entity class:

@NamedQuery(name = "byNameLike", query = "SELECT p FROM Person p WHERE name like ?1",
  hints = { @QueryHint(name = "org.hibernate.cacheable", value = "true") })

Logging:

Enabled org.hibernate.SQL category.

edited Jun 3, 2012 at 15:01

robert

34.6k8 gold badges55 silver badges74 bronze badges

answered Jun 3, 2012 at 13:29

lehphyro

2013 silver badges9 bronze badges

Comments

serg · Accepted Answer · 2010-05-20 20:31:29Z

0

Take a look at hibernate query cache feature.

You can also use some lightweight standalone caching solution, like OSCache. It gives you full control over what, when, and how is cached, but you will need to also think when to refresh the cache.

answered May 20, 2010 at 20:31

serg

112k78 gold badges326 silver badges337 bronze badges

2 Comments

Sameer Malhotra Over a year ago

I checked the link which you have provided but its not going to help me because I am using the same method and again next time I am calling the same method with different arguments(code1, code2, code3 etc.) so the previous data will be flushed automatically since its the same query only with different parameters.

Sameer Malhotra Over a year ago

I got another solution as follows: if (query instanceof org.hibernate.ejb.QueryImpl) { logger .info("Yes the query is of the instance org.hibernate.ejb.QueryImpl so alreaedy set the cacheable true"); ((org.hibernate.ejb.QueryImpl) query).getHibernateQuery() .setCacheable(true); } do u think it might work...

chammp · Accepted Answer · 2011-10-26 10:04:44Z

-2

You don't see anything in the log because Cache doesn't inform you abozt hits/misses per default. Use statistics="true" on your defaultCache element to include information about this.

Hibernate sadly logs the sql statements to the console even if the hit comes from the cache.

answered Oct 26, 2011 at 10:04

chammp

51 bronze badge

1 Comment

Conor Power Over a year ago

"Hibernate sadly logs the sql statements to the console even if the hit comes from the cache." Not true.

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