Disable Hibernate Session Cache (?)

csfidan · **Joined:** Wed Apr 23, 2008 4:07 pm **Posts:** 1

Hibernate version: Hibernate 3.2.4.sp1

I am using Hibernate as part of the Seam framework. My problem is when a field is updated by an external application the change is not reflected in the web interface.

For example, I display a data table backed by a query:

Code:

entityManager.createQuery("select c from Channel c").getResultList();

Then after changing a Channel field using an external application and refreshing the page, I see the same stale result from the first query.

However, if I do:

Code:

entityManager.clear();
entityManager.createQuery("select c from Channel c").getResultList();

The fields are refreshed from the database.

I believe Hibernate is pulling the results from its session cache, so I've tried to turn off the session cache by adding the following to my persistence.xml file:

Code:

<property name="hibernate.cache.use_second_level_cache" value="false" />
<property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider" />

and it appears to be disabled when the application starts:

Code:

16:43:41,839 INFO  [SettingsFactory] Second-level cache: disabled
16:43:41,840 INFO  [SettingsFactory] Query cache: disabled

but they have no effect.

I can hack around this by sprinkling entityManager.clear() and entityManager.refresh(c) throughout my code, but I'd prefer to set a configuration option and have the changes application wide.

Can someone point me in the right direction?

Thanks,
Dan

prats · **Posted:** Wed Apr 23, 2008 11:07 pm

can you pls put your hibernate properties as well.

christian · **Posted:** Thu Apr 24, 2008 3:02 am

The second-level cache has nothing to do with the first-level (session or persistence context) cache. The persistence context/session cache is mandatory for various reasons. In fact, not understanding this crucial part and ignoring it in application architecture is a recipe for disaster. There is no quick solution here, study some documentation.

(No need to post properties.)

ferozz · **Posted:** Thu Apr 24, 2008 3:44 am

either u will use refresh or evict object and then load them, or u can use stateless session but u will loose a lot o features http://www.hibernate.org/hib_docs/v3/re ... esssession

obourdon · **Joined:** Sat Jan 05, 2008 7:33 am **Posts:** 26

> The second-level cache has nothing to do with the first-level (session or persistence context) cache. The persistence context/session cache is mandatory for various
> reasons. In fact, not understanding this crucial part and ignoring it in application architecture is a recipe for disaster. There is no quick solution here, study some documentation.

this remark might usually make a lot of sense but under certain circumstances the session cache might have very nasty side effects
what do you think the following sql query result would be when 2 separate threads execute roughly at the same time ?
String lockStr = "SELECT GET_LOCK('" + c + "_" + id + "',5)";
SQLQuery qq = sqlQuery(lockStr);
List<Object[]> res = qq.list();

my take would be that using the cache the user will be in great trouble because both queries will return 1 (I've got the lock) where they should definitely not !!!

csfidan15 · **Posted:** Fri May 20, 2011 8:58 am

obourdon wrote:

this remark might usually make a lot of sense but under certain circumstances the session cache might have very nasty side effects
what do you think the following sql query result would be when 2 separate threads execute roughly at the same time ?
String lockStr = "SELECT GET_LOCK('" + c + "_" + id + "',5)";
SQLQuery qq = sqlQuery(lockStr);
List<Object[]> res = qq.list();

my take would be that using the cache the user will be in great trouble because both queries will return 1 (I've got the lock) where they should definitely not !!!

It's too late unfortunately) But anyway thanks)