4.2.4. How to host several JCR instances on the same database instance?

Warning

You are looking at documentation for an older release. Not what you want? See the current release documentation.

Frequently, a single database instance must be shared by several other applications, but you can host several JCR instances in the same database instance. To fulfill this need, you have to review your queries and scope them to the current schema; it is now possible to have one JCR instance per DB schema instead of per DB instance. Also, you will need to apply the configuration changes described below.

Lock Manager configuration

To enable this feature, you need to replace org.jboss.cache.loader.JDBCCacheLoader with org.exoplatform.services.jcr.impl.core.lock.jbosscache.JDBCCacheLoader in the JBossCache configuration file.

Here is an example of this very part of the configuration:


<jbosscache xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="urn:jboss:jbosscache-core:config:3.1">



   <locking useLockStriping="false" concurrencyLevel="500" lockParentForChildInsertRemove="false"

      lockAcquisitionTimeout="20000" />



   <clustering mode="replication" clusterName="${jbosscache-cluster-name}">

      <stateRetrieval timeout="20000" fetchInMemoryState="false" />

      <sync />

   </clustering>



   <loaders passivation="false" shared="true">

      <!-- All the data of the JCR locks needs to be loaded at startup -->

      <preload>

         <node fqn="/" />

      </preload>  

      <!--

      For another cache-loader class you should use another template with

      cache-loader specific parameters

      -->

      <loader class=


 async="false" fetchPersistentState="false"

         ignoreModifications="false" purgeOnStartup="false">

         <properties>

            cache.jdbc.table.name=${jbosscache-cl-cache.jdbc.table.name}

            cache.jdbc.table.create=${jbosscache-cl-cache.jdbc.table.create}

            cache.jdbc.table.drop=${jbosscache-cl-cache.jdbc.table.drop}

            cache.jdbc.table.primarykey=${jbosscache-cl-cache.jdbc.table.primarykey}

            cache.jdbc.fqn.column=${jbosscache-cl-cache.jdbc.fqn.column}

            cache.jdbc.fqn.type=${jbosscache-cl-cache.jdbc.fqn.type}

            cache.jdbc.node.column=${jbosscache-cl-cache.jdbc.node.column}

            cache.jdbc.node.type=${jbosscache-cl-cache.jdbc.node.type}

            cache.jdbc.parent.column=${jbosscache-cl-cache.jdbc.parent.column}

            cache.jdbc.datasource=${jbosscache-cl-cache.jdbc.datasource}

         </properties>

      </loader>

   </loaders>

</jbosscache>

You can also obtain a file example from GitHub.

HibernateService configuration

If you use HibernateService for JDBC connections management, you will need to specify explicitly the default schema by setting the "hibernate.default_schema" property in the configuration of HibernateService.

Here is an example:


<component>

    <key>org.exoplatform.services.database.HibernateService</key>

    <jmx-name>database:type=HibernateService</jmx-name>

    <type>org.exoplatform.services.database.impl.HibernateServiceImpl</type>

    <init-params>

      <properties-param>

        <name>hibernate.properties</name>

        <description>Default Hibernate Service</description>

        ...........

        




      </properties-param>

    </init-params>

</component>