Ehcache Settings for Queries

This cache is used if you use a query cache without setting a name. A typical ehcache.xml configuration is:

Tracks the timestamps of the most recent updates to particular tables. It is important that the cache timeout of the underlying cache implementation be set to a higher value than the timeouts of any of the query caches. In fact, it is recommend that the underlying cache not be configured for expiry at all. A typical ehcache.xml configuration is:

In addition, a QueryCache can be given a specific name in Hibernate using Query.setCacheRegion(String name). The name of the cache in ehcache.xml is then the name given in that method. The name can be whatever you want, but by convention you should use “query.” followed by a descriptive name. For example:

Let's say you have a common query running against the Country Domain. Here is the code to use a query cache with it:

public List getStreetTypes(final Country country) throws HibernateException {
final Session session = createSession();
try {
final Query query = session.createQuery(
"select st.id, st.name"
+ " from StreetType st "
+ " where st.country.id = :countryId "
+ " order by st.sortOrder desc, st.name");
query.setLong("countryId", country.getId().longValue());
query.setCacheable(true);
query.setCacheRegion("query.StreetTypes");
return query.list();
} finally {
session.close();
}
}

The query.setCacheable(true) line caches the query. The query.setCacheRegion("query.StreetTypes") line sets the name of the Query Cache. Alex Miller has a good article on the query cache here.

None of the read-write, nonstrict-read-write and read-only policies apply to Domain Objects. Cache policies are not configurable for query cache. They act like a non-locking read only cache.