C3p0 connection pooling for jpa in persistence.xml not working?

Question

I'm still getting JDBC timeouts after trying to configure c3p0 following all of the examples I could find. I'm using JPA, Hibernate, Tomcat, MySQL [AWS RDS]. Here's the snippet from persistence.xml:

<property name="javax.persistence.jdbc.url"
value="jdbc:mysql://url..." />
<property name="javax.persistence.jdbc.driver" value="com.mysql.jdbc.Driver" />
<property name="hibernate.dialect" value="org.hibernate.dialect.MySQLDialect" />
<property name="connection.provider_class"  value="org.hibernate.connection.C3P0ConnectionProvider"/>
<property name="hibernate.c3p0.acquire_increment" value="4" />
<property name="hibernate.c3p0.idle_test_period" value="3000" /> 
<property name="hibernate.c3p0.max_size" value="100" />
<property name="hibernate.c3p0.max_statements" value="15" />
<property name="hibernate.c3p0.min_size" value="5" />
<property name="hibernate.c3p0.timeout" value="100" /> 

And the error log: 09:18:51.776 WARN org.hibernate.util.JDBCExceptionReporter - SQL Error: 0, SQLState: 08S01 09:18:51.777 ERROR org.hibernate.util.JDBCExceptionReporter - The last packet successfully received from the server was 38,491,585 milliseconds ago. ...

Answer 1

The configuration looks OK. Activate logging and make sure that C3P0 is starting with the appropriate settings.

2010-10-16 11:58:31,271 INFO [main] o.h.c.ConnectionProviderFactory [ConnectionProviderFactory.java:173] Initializing connection provider: org.hibernate.connection.C3P0ConnectionProvider
...