JPA Connection Pooling

OpenJPA does not use any kind of connection pooling out of the box, but no worries for those of you using openJPA on WebSphere. When running on WebSphere, the application server provides production-quality connection pooling. That is great if your application runs on WAS, not so great otherwise. Since I haven't found a *good* reason why anyone would run without connection pooling, it seems like a good topic for a first post.

Modifying an existing application to use connection pooling couldn't be easier. To start, you're going to need to download the Apache Commons Pool and DBCP components and add them to your application classpath. Next you will need to update the application database connection properties. Below is an example openJPA configuration using DBCP. You will need to update the connection info where appropriate if using a different DB. Note that these properties are being set in the META-INF/persistence.xml file, but you can also set the JVM system properties directly.

<property name="openjpa.ConnectionDriverName" value="org.apache.commons.dbcp.BasicDataSource"/>
<property name="openjpa.ConnectionProperties" value="DriverClassName=com.mysql.jdbc.Driver,Url=jdbc:mysql://localhost/test,Username=root,Password=password"/>

Configuring openJPA to use connection pooling is as simple as that. I created a small JSE application for this post that uses both pooled and non-pooled connections to do 1000 selects on an empty table. Even though the example is very simple, the results are pretty impressive.

• 1000 selects with no connection pooling took ~23.469 seconds.
• 1000 selects with connection pooling took ~1.234 seconds.

-Rick