Hi,

I have two different applications using the same database. The first application is using hibernate to access the database. The second application is using the same database directly with JDBC. If the application using JDBC writes somthing into database, I do not get this changes in my hibernate application, because I am using the hibernate query cache. How can I solve this without to disable the QueryCache? Is it possible to trigger the QueryCache to be discarded or reloaded?

My configuration:
Hibernate version: 3.1.2

Postgres Database: PostgreSQL, version: 8.0.3

Any help is appreciated

scara

What Cache provider are you using? (<hibernate-configuration>...)

I am using org.hibernate.cache.StandardQueryCache.

the configuration file is below:

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://localhost/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<property name="dialect">org.hibernate.dialect.PostgreSQLDialect</property>
<property name="connection.driver_class">org.postgresql.Driver</property>
<property name="connection.username">postgres</property>
<property name="connection.password">postgres</property>
<property name="connection.url">jdbc:postgresql://localhost:5432/pep_dev</property>

<!-- built-in JDBC connection pool is not for production environment! disabled -->
<property name="connection.pool_size">0</property>
<property name="c3p0.min_size">5</property>
<property name="c3p0.max_size">50</property>
<property name="c3p0.timeout">1800</property>
<property name="c3p0.max_statements">50</property>
<property name="c3p0.acquire_increment">1</property>

<property name="cache.provider_class">org.hibernate.cache.EhCacheProvider</property>

<property name="generate_statistics">true</property>
<property name="cache.use_second_level_cache">true</property>
<property name="cache.use_query_cache">true</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>

<mapping resource="Dimensionen.hbm.xml" />
....
</hibernate-configuration>

"Queries are not cached in the query cache, unless you explicitly call Query.setCacheable(true), even when the query cache is enabled."

"If the query should force a refresh of its query cache region, you should call Query.setCacheMode(CacheMode.REFRESH). This is particularly useful in cases where underlying data may have been updated via a separate process (i.e., not modified through Hibernate) and allows the application to selectively refresh particular query result sets. This is a more efficient alternative to eviction of a query cache region via SessionFactory.evictQueries(). " - Hibernate reference doc.

Your are using EhCache

(
<property name="cache.provider_class">org.hibernate.cache.EhCacheProvider</property> )

From the EHCache documentation (http://ehcache.sourceforge.net/EhcacheU ... id.s13.1.1):

Expiry Strategy

One thread per cache is used to remove expired elements. The optional attribute diskExpiryThreadIntervalSeconds sets the interval between runs of the expiry thread. Warning: setting this to a low value is not recommended. It can cause excessive DiskStore locking and high cpu utilisation. The default value is 120 seconds.

So you need to configure the EHCACHE in Hibernate. This link will help you:
http://ehcache.sourceforge.net/EhcacheU ... tml#id.s15