Hi,

We would like to use hibernate second level cache(EHcache) in our system, but only for several sub-classes.
We tried to put cache annotation only in the hbm of the sub-class but the we got an exception.
When we put the cache annotation on the abstract parent class - we didn't get the exception.

Is there a way to enable the second level cache only on the sub-class?


We are using hibernate-core-3.6.9.Final.jar, hibernate-ehcache-3.6.9.Final.jar, ehcache-core-2.6.5.jar

This our parent class hbm:

<hibernate-mapping default-access="field">
<class name="com.cisco.prime.inventory.service.CustomerFacingService" table="CustomerFacingService" discriminator-value="CustomerFacingService">
<id name="instanceId" column="ID" type="long" unsaved-value="0" access="property">
<generator class="seqhilo">
<param name="max_lo">1000</param>
</generator>
</id>.........


This is our child class hbm:

<hibernate-mapping default-access="field">
<subclass name="com.cisco.prime.inventory.service.VirtualConnection" discriminator-value="VirtualConnection" dynamic-update="true" extends="com.cisco.prime.inventory.service.CustomerFacingService">
<cache usage="read-write" region="com.cisco.prime.inventory.service.CustomerFacingService"></cache>
<many-to-one name="linkRFS0" class="com.cisco.prime.inventory.rfs.LinkRFS" not-found="ignore" foreign-key="none">
<column name="LinkRFS0_ID" unique="true"/>
</many-to-one>
<set name="endpoints" cascade="delete,save-update,delete-orphan">
<key>
<column name="VirtualConnection_ID"/>
</key>
<one-to-many class="com.cisco.prime.inventory.service.ServiceEndpoint"/>
<filter name="dataFilter" condition="AuthEntityId in (SELECT DISTINCT sep.ID FROM serviceEndpoint sep, linkterminationpoint ltps, xgs_groupmembers gm WHERE sep.ENDPOINTRFS_ID = ltps.ID AND ltps.NETWORKRESOURCE_ID = gm.memberid AND gm.GroupId in (:domainIds))"/>
</set>

Second level cache configuration:

hibernate.cache.region.factory_class=net.sf.ehcache.hibernate.EhCacheRegionFactory
hibernate.cache.use_second_level_cache=true
hibernate.cache.use_query_cache=true


ehcache.xml:

<?xml version="1.0" encoding="UTF-8"?>
<ehcache name="liel-cache" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:noNamespaceSchemaLocation="ehcache.xsd" updateCheck="true"
monitoring="autodetect" dynamicConfig="true">

<diskStore path="java.io.tmpdir/ehcache" />

<defaultCache maxEntriesLocalHeap="10000" eternal="false"
timeToIdleSeconds="120" timeToLiveSeconds="120" diskSpoolBufferSizeMB="30"
maxEntriesLocalDisk="10000000" diskExpiryThreadIntervalSeconds="120"
memoryStoreEvictionPolicy="LRU" statistics="true">
<persistence strategy="localTempSwap" />
</defaultCache>

<cache name="com.cisco.prime.inventory.service.CustomerFacingService" maxEntriesLocalHeap="10000" eternal="false"
timeToIdleSeconds="5" timeToLiveSeconds="10">
<persistence strategy="localTempSwap" />
</cache>

<cache name="org.hibernate.cache.internal.StandardQueryCache"
maxEntriesLocalHeap="5" eternal="false" timeToLiveSeconds="120">
<persistence strategy="localTempSwap" />
</cache>

<cache name="org.hibernate.cache.spi.UpdateTimestampsCache"
maxEntriesLocalHeap="5000" eternal="true">
<persistence strategy="localTempSwap" />
</cache>
</ehcache>

Interesting question. I tried to see if this works with Hibernate 5.2 and it does now. I asked the question the mailing list to see if there's any reason why we don;t support this behavior.

Nevertheless, if we fix it, it's going to be in 5.x, and not in 3.x or 4.x, so you'll have to upgrade Hibernate to get it, in that case.

Thanks for the quick reply!

As detailed in Sanne's reply, this is very difficult to achieve in practice. For this reason, we need to stick to a single CacheConcurrencyStrategy for a given inheritance tree.