C3P0 Connections are not released on undeply

[Suresh Khant]

Hi All,

I am using c3p0 with the hibernate for connection pooling ,

I have noticed that when i undeploy the application the database connections are not released , to release them i need to restart the application server which is jboss 7

here is my C3P0 configuration

   <!-- 
            Configuring c3p0 connection pool 
            The connection pool is must in production to avoid CommunicationException error
        -->
        <property name="connection.provider_class">org.hibernate.service.jdbc.connections.internal.C3P0ConnectionProvider</property>
        <property name="hibernate.c3p0.min_size">10</property>
        <property name="hibernate.c3p0.max_size">15</property>
        <property name="hibernate.c3p0.timeout">300</property> <!-- in seconds. must be less than wait_timeout variable in mysql. change it to 300 -->
        <property name="hibernate.c3p0.max_statements">50</property>
        <property name="hibernate.c3p0.idle_test_period">3000</property> <!-- in seconds -->

my pom file contains

  <!-- Hibernate Files -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-core</artifactId>
            <version>4.1.9.Final</version>
        </dependency>
        
        <!-- Hibernate c3p0 connection pool -->
        <dependency>
            <groupId>org.hibernate</groupId>
            <artifactId>hibernate-c3p0</artifactId>
            <version>4.1.9.Final</version>
        </dependency>

Are my settings are right ? is there any property to release the created database connections , is C3P0 the best choice to manage the connection pool ?

[Jaikiran Pai]

How are you testing that the connections aren't released?

The file you posted looks like a hibernate configuration file. Is that right? If yes, how are you using Hibernate in your application? Are you setting up the entitymanagers yourself?

[Suresh Khant]

Hi Pai , Thanks for your reply ,

How are you testing that the connections aren't released?

By listing the number of database connections using the mysql command
show processlist;

executing this command after deploying of the application( and running it ) and after undeploy of the application

The file you posted looks like a hibernate configuration file. Is that right? If yes, how are you using Hibernate in your application?

yes it is hibernate configuration file along with C3P0 configuration ,

part of Hibernate configuration file :

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
  <session-factory>
    <property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
    <property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
    <property name="hibernate.connection.url">jdbc:mysql://localhost:3306/hr_system?zeroDateTimeBehavior=convertToNull&useUnicode=true&characterEncoding=UTF-8</property>
    <property name="hibernate.connection.username">username</property>
    <property name="hibernate.connection.password">password</property>

 

<!--   
            Configuring c3p0 connection pool   
            The connection pool is must in production to avoid CommunicationException error  
        -->  
        <property name="connection.provider_class">org.hibernate.service.jdbc.connections.internal.C3P0ConnectionProvider</property>  
        <property name="hibernate.c3p0.min_size">10</property>  
        <property name="hibernate.c3p0.max_size">15</property>  
        <property name="hibernate.c3p0.timeout">300</property> <!-- in seconds. must be less than wait_timeout variable in mysql. change it to 300 -->  
        <property name="hibernate.c3p0.max_statements">50</property>  
        <property name="hibernate.c3p0.idle_test_period">250</property> <!-- in seconds -->  

I am using hibernate as the following

Hibernateutil class

public class HibernateUtil {

    private static final SessionFactory sessionFactory;
    
    static {
        try {
            // Create the SessionFactory from standard (hibernate.cfg.xml) 
            // config file.
            //sessionFactory = new AnnotationConfiguration().configure().buildSessionFactory();
            sessionFactory = new Configuration().configure().buildSessionFactory();
        } catch (Throwable ex) {
            // Log the exception. 
            System.err.println("Initial SessionFactory creation failed." + ex);
            throw new ExceptionInInitializerError(ex);
        }
    }
    
    public static SessionFactory getSessionFactory() {
        return sessionFactory;
    }
}

Example to save entity

public void addUser(User user){

	Session session = null;
	try{
		session = HibernateUtil.getSessionFactory().openSession();
        	session.beginTransaction();
        	session.save(user);
        	session.getTransaction().commit();
	}catch{
		//TODO handling exception
	}finally{
		if (session.isOpen())
	        	session.close();
	}
}

Are you setting up the entitymanagers yourself

Frankly i dont know what do you mean by entitymanagers , but i ll check that