spring + hibernate + ehcache 2nd level cache?

[billharris]

I'm using hibernate 3.0.4 and spring 1.2.1. I'm doing a very simple proof of concept to learn hibernate. I have a table consisting of 3 columns: id, city and zipcode. the query is given the city, i want the zipcodes. I want to use the 2nd level cache to prevent a db hit for each request. everything seems to be working except the caching.

For a local db with spring, hibernate + ehcache:
1st request: ~700ms, 2nd request 40ms, 3rd request 30ms, 4th request 180ms.

Using spring's jdbc functionality, i get repsonse times along the lines of 1: ~700ms, 2: 0ms, 3: 0ms....

jdbc is working much faster. i would think if the cache was being accessed then i would have similar performance.

what are the requirements that need to be fulfilled to utilize the 2nd level cache?


here are some excerpts from my log & config files:

Second-level cache: enabled
Query cache: disabled
Cache provider: org.hibernate.cache.EhCacheProvider
Optimize cache for minimal puts: disabled
Structured second-level cache entries: disabled
<snip>
 com.mytest.model.CityZip Cache: Using SpoolingLinkedHashMap implementation
 initialized MemoryStore for com.mytest.model.CityZip
 Initialised cache: com.mytest.model.CityZip
 instantiating cache region: com.mytest.model.CityZip usage strategy: read-only
read-only cache configured for mutable class: com.mytest.model.CityZip
<snip>
result row: EntityKey[com.mytest.model.CityZip#66]
Initializing object from ResultSet: [com.mytest.model.CityZip#66]
Hydrating entity: [com.mytest.model.CityZip#66]
<snip>
total objects hydrated: 19
<snip>
resolving associations for [com.mytest.model.CityZip#35]
adding entity to second-level cache: [com.mytest.model.CityZip#35]
Caching: com.mytest.model.CityZip#35
done materializing entity [com.mytest.model.CityZip#35]

not sure what i am missing. i would think there would be some message stating it was accessing the cache.
my class com.mytest.model.CityZip has the equals and hashcode methods overridden


inside my dao which extends HibernateDaoSupport:

getHibernateTemplate().setCacheQueries(true); 
List tmp = getHibernateTemplate().find(query, city);

ehcache xml file has:

    <defaultCache
        maxElementsInMemory="10000"
        eternal="false"
        timeToIdleSeconds="120"
        timeToLiveSeconds="120"
        overflowToDisk="true"
        diskPersistent="false"
        diskExpiryThreadIntervalSeconds="120"
        />
        
    <cache name="com.mytest.model.CityZip"
        maxElementsInMemory="80"
        eternal="true"
        overflowToDisk="false"
        />

hibernate xml file has:

	<class name="com.mytest.model.CityZipZip" table="cityzip">
		<cache usage="read-only"/>
		<id name="id" column="cityzip_id">
			<generator class="identity"/>
		</id>
		<property name="zipcode" column="zipcode"/>
		<property name="city" column="city"/>
	</class>

[Costin Leau]

Take a look at the EhCache documentation from the home page (http://ehcache.sourceforge.net/documentation/). EhCache is the default cache provider for Hibernate. There are also some entries inside the reference documentation of Hibernate. Note that Spring can't actually help you much with caching - it's yours and HB job to actually hit the cache.
Note that for effective cache use you need to use identities which is not what your are doing with find (think of session.load). However you can define caching for queries but for that you have to check the documentation of HB and EhCache but note that no matter what approach you take, caching is a LOT more effective with identities than queries.