Multitenancy with Hibernate using its dedicated features or not?

Question

When developping a multitenant Java web application with Hibernate 4.1.12 we found two configuration modes that seem to work, one with Hibernate multitenancy features, one without.

The hibernate.cfg.xml looks like;

<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
    "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
    "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
    <!-- Standard configuration -->
    <property name="hibernate.dialect">org.hibernate.dialect.DB2Dialect</property>
    <property name="hibernate.show_sql">true</property>
    <property name="hibernate.format_sql">false</property>
    <property name="hibernate.connection.autocommit">true</property><!-- legacy non-transactional DB -->

    <!-- HERE LIES THE MULTITENANCY CONFIGURATION -->

    <!-- Persistent classes -->
    <mapping class="com.foo.model.Bar1"/>
    <mapping class="com.foo.model.Bar2"/>
    <!-- Other entities here -->
</session-factory>

Multitenancy configuration "with Hibernate multitenancy features" is:

    <!-- Multitenancy configuration (with Hibernate multitenancy support) -->
    <property name="hibernate.multiTenancy">DATABASE</property>
    <property name="hibernate.tenant_identifier_resolver">com.foo.hibernate.TenantResolverImpl</property>
    <property name="hibernate.multi_tenant_connection_provider">com.foo.hibernate.MultiTenantConnectionProviderImpl</property>
    <property name="hibernate.current_session_context_class">com.foo.hibernate.CurrentSessionContextImpl</property>
    <property name="hibernate.temp.use_jdbc_metadata_defaults">false</property>

Multitenancy configuration "without Hibernates multitenancy features" is:

    <!-- Multitenancy configuration (without Hibernate multitenancy suport, only home made multitenancy) -->
    <property name="hibernate.connection.provider_class">com.foo.hibernate.ConnectionProviderImpl</property>
    <property name="hibernate.current_session_context_class">com.foo.hibernate.CurrentSessionContextImpl</property>
    <property name="hibernate.temp.use_jdbc_metadata_defaults">false</property>

Some implementation details:

• TenantResolverImpl returns the name of the current tenant, obtained from a thread local
• MultiTenantConnectionProviderImpl and ConnectionProviderImpl return a connection from a JDBC datasource whose JNDI name is built from the tenant name (e.g. String datasourceName = "java:comp/env/" + tenantName "_DS"
• CurrentSessionContextImpl stores multiple session in a ThreadLocal<String, Session> where the String is the tenant name (we do not use Hibernate "current session" implementations because of what I described in https://stackoverflow.com/questions/24886780/limitation-of-hibernate-current-session-for-multitenant-application)

So far both have been working fine.

The question is: what are the differences between these two modes?

Thank you for your time.

Answer 1

It is better to use the explicit form with hibernate.multiTenancy which does a few additional sanity checks and is more future proof in case new services/components become involved in multi-tenancy in the future.

But what you do explicitly is mostly what the hibernate.multiTenancy is about. It works in your case because you have decided essentially to implement your own connection provider, disabled the JDBC metadata check and do not make use of the schema generation feature (in the "non explicitly multitenant" configuration).