Infinispan JPA 2nd Level Caching on JBoss AS 7 - Minimal Working Example

Infinispan is included in the JBoss AS 7 distribution as the default second level cache for Hibernate.
For my presentation on the JBoss One Day Talk 2013,
I was looking for the most simple example to be used in a demo.
This post shows how to get Infinispan Hibernate 2nd Level Caching up and running in five minutes.
It should also work with the upcoming WildFly Application Server.

Step 1: Example Project from Maven Archetype
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JBoss have prepared a maven archetype that can be used to create a simple JEE web application.
We use this application as a a starting point:

mvn archetype:generate \
    -DarchetypeArtifactId=jboss-javaee6-webapp-archetype \
    -DarchetypeGroupId=org.jboss.spec.archetypes \
    -DarchetypeVersion=7.1.2.Final \
    -DgroupId=de.consol.research \
    -DartifactId=infinispan-jpa-example \
    -Dversion=1.0-SNAPSHOT \
    -Dname="Infinispan JPA Example" \
    -DarchetypeCatalog=http://search.maven.org/remotecontent?filepath=archetype-catalog.xml \
    -DinteractiveMode=false

The generated application has the JBoss AS 7 Maven Plugin included in its pom.xml, and can be run from the command line as follows:

cd infinispan-jpa-example
mvn clean verify jboss-as:run

This will download and run the JBoss Application Server and deploy the example application. The application will become available on http://localhost:8080/infinispan-jpa-example.

jboss-javaee6-webapp-archetype

The application maintains a list of Members in an SQL database. Each member has the following attributes:

  • Name
  • Email
  • Phone number

There is a JSF page that can be used to add new members to the list, and there is a REST interface that can be used to query members by ID:

Step 2: Enable Database Logging

In order to see the effect of the L2 caching, we need to enable logging on the database level to see the SQL queries performed.

As part of the example project, the file src/main/resources/import.sql was created. Hibernate will execute this file when the application is deployed. This is used to populate the database with an example Member when the application starts up.

As we know that JBoss uses H2 as its default database, we can add an H2 specific command to import.sql in order to enable logging of SQL commands on the database level:

SET TRACE_LEVEL_SYSTEM_OUT 2;
insert into Member (id, name, email, phone_number) values (0, 'John Smith', 'john.smith@mailinator.com', '2125551212');

When the application is re-started, we can now observe in the console output that each request to http://localhost:8080/infinispan-jpa-example/rest/members/0 triggers an SQL query on the database.

Step 3: Enabling Infinispan L2 Cache

To enable Infinispan as a 2nd Level Cache for JPA applications, two lines need to be added to persistence.xml. First, directly after the jta-data-source and before the properties, the shared-cache-mode needs to be set:

<shared-cache-mode>DISABLE_SELECTIVE</shared-cache-mode>

Secondly, an additional property must be added to the properties list:

<property name="hibernate.cache.use_second_level_cache" value="true"/>

The shared cache mode DISABLE_SELECTIVE means that all JPA entities are cached unless caching is explicitly disabled via annotations. That way, all the Member entities in the example application become subject to caching.

The property simply enables caching for hibernate.

After restarting the application, we can see in the console output that only the first access to the REST interface http://localhost:8080/infinispan-jpa-example/rest/members/0 triggers a query on the database level, all subsequent queries are served from the cache.

Where to go from here

This post showed how to get Infinispan up and running as a 2nd level Hibernate cache in a simple JPA application. The next steps would be to:

Monitoring-Workshop 2017 12./13.9. Düsseldorf