Hibernate version: 3.2.4

Hi,

I'm using the query cache with Ehcache and the JPA implementation.

My request returns 3 elements from the database. Everything is fine.
But when Hibernate tries to retrieve the objects from the query cache the list is composed of null objects,

Here is the logs:

DEBUG org.hibernate.jdbc.ConnectionManager - opening JDBC connection
DEBUG org.springframework.jdbc.datasource.DriverManagerDataSource - Creating new JDBC Connection to [jdbc:oracle:thin:@psdev01:1522:IDTV3DU2]
DEBUG org.hibernate.SQL - select * from ( select episodes1_.XID as XID0_, episodes1_.COMMENTS as COMMENTS0_, episodes1_.MAIN_CONTENT_ID as MAIN13_0_, episodes1_.PUBLIC_ID as PUBLIC4_0_, episodes1_.TITLE as TITLE0_, episodes1_.TYPE_SUBTYPE_LIST as TYPE6_0_, episodes1_.VERSION as VERSION0_, episodes1_.APPROX_DURATION as APPROX8_0_, episodes1_.SEASON_ID as SEASON11_0_, episodes1_.SEQ_NUMBER as SEQ9_0_, episodes1_.SEQ_NUMBER_DISPLAY as SEQ10_0_, episodes1_.CLASS as CLASS0_ from DT3_CON_CONTENT season0_ inner join DT3_CON_CONTENT episodes1_ on season0_.XID=episodes1_.SEASON_ID where season0_.CLASS='com.lysis.idtv3.content.adaptors.PSeason' and season0_.XID=? ) where rownum <= ?
DEBUG org.hibernate.jdbc.AbstractBatcher - about to open ResultSet (open ResultSets: 0, globally: 0)
DEBUG org.hibernate.loader.Loader - result row: EntityKey[com.lysis.idtv.model.VideoContent#38856]
DEBUG org.hibernate.loader.Loader - result row: EntityKey[com.lysis.idtv.model.VideoContent#165666]
DEBUG org.hibernate.loader.Loader - result row: EntityKey[com.lysis.idtv.model.VideoContent#165665]
DEBUG org.hibernate.jdbc.AbstractBatcher - about to close ResultSet (open ResultSets: 1, globally: 1)
DEBUG org.hibernate.jdbc.AbstractBatcher - about to close PreparedStatement (open PreparedStatements: 1, globally: 1)
DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
DEBUG org.hibernate.jdbc.ConnectionManager - releasing JDBC connection [ (open PreparedStatements: 0, globally: 0) (open ResultSets: 0, globally: 0)]
DEBUG org.hibernate.engine.TwoPhaseLoad - resolving associations for [com.lysis.idtv.model.Production#38856]
DEBUG org.hibernate.engine.TwoPhaseLoad - done materializing entity [com.lysis.idtv.model.Production#38856]
DEBUG org.hibernate.engine.TwoPhaseLoad - resolving associations for [com.lysis.idtv.model.Production#165666]
DEBUG org.hibernate.engine.TwoPhaseLoad - done materializing entity [com.lysis.idtv.model.Production#165666]
DEBUG org.hibernate.engine.TwoPhaseLoad - resolving associations for [com.lysis.idtv.model.Production#165665]
DEBUG org.hibernate.engine.TwoPhaseLoad - done materializing entity [com.lysis.idtv.model.Production#165665]
DEBUG org.hibernate.engine.StatefulPersistenceContext - initializing non-lazy collections
DEBUG org.hibernate.cache.StandardQueryCache - caching query results in region: org.hibernate.cache.StandardQueryCache; timestamp=4862990954733569
DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection

....

Great, I have my 3 objects:
INFO com.XXX.service.impl.SeriesServiceImpl - results = [com.lysis.idtv.model.Production@1563e06, com.lysis.idtv.model.Production@10204ce, com.lysis.idtv.model.Production@1898b92]

....

And then for the next calls:

...

DEBUG org.hibernate.impl.SessionImpl - opened session at timestamp: 4862990955245572
DEBUG org.hibernate.cache.StandardQueryCache - checking cached query results in region: org.hibernate.cache.StandardQueryCache
DEBUG net.sf.ehcache.hibernate.EhCache - key: sql: select episodes1_.XID as XID0_, episodes1_.COMMENTS as COMMENTS0_, episodes1_.MAIN_CONTENT_ID as MAIN13_0_, episodes1_.PUBLIC_ID as PUBLIC4_0_, episodes1_.TITLE as TITLE0_, episodes1_.TYPE_SUBTYPE_LIST as TYPE6_0_, episodes1_.VERSION as VERSION0_, episodes1_.APPROX_DURATION as APPROX8_0_, episodes1_.SEASON_ID as SEASON11_0_, episodes1_.SEQ_NUMBER as SEQ9_0_, episodes1_.SEQ_NUMBER_DISPLAY as SEQ10_0_, episodes1_.CLASS as CLASS0_ from DT3_CON_CONTENT season0_ inner join DT3_CON_CONTENT episodes1_ on season0_.XID=episodes1_.SEASON_ID where season0_.CLASS='com.lysis.idtv3.content.adaptors.PSeason' and season0_.XID=?; parameters: ; named parameters: {season=39092}; first row: 0; max rows: 3
DEBUG org.hibernate.cache.StandardQueryCache - Checking query spaces for up-to-dateness: [DT3_CON_CONTENT]
DEBUG net.sf.ehcache.hibernate.EhCache - key: DT3_CON_CONTENT
DEBUG net.sf.ehcache.hibernate.EhCache - Element for DT3_CON_CONTENT is null
DEBUG org.hibernate.cache.StandardQueryCache - returning cached query results
DEBUG org.hibernate.jdbc.ConnectionManager - aggressively releasing JDBC connection
...

An now the values are null:
INFO com.XXX.service.impl.SeriesServiceImpl - results = [null, null, null]



Any ideas?
Thanks in advance.
J.

Does someone use query cache (Ehcache) and Jpa?

Just to know if I did something wrong.

Thanks.
J.

Do you have your ehcache.xml file properly configured?

My cached queries were not retrieving the objects properly until I set up the objects *themselves* in ehcache.xml. Until that happened, it was noticing that the query had been executed before, but it was failing to find the objects of the result-set.

Here's an example of declaring the objects themselves in the ehcache.xml: