MySQL + JPA+ Hibernate + C3P0 + Tomcat

Estou com um problema na minha aplicação web no banco de dados MySQL. Estou usando JPA e a cada request a aplicacao cria um novo EntityManager usando um filter:

public class EntityManagerFilter implements Filter {

	@Override
	public void init(FilterConfig filterConfig) throws ServletException {}

	@Override
	public void destroy() {}

	@Override
	public void doFilter(ServletRequest request, ServletResponse response, FilterChain chain) throws IOException, ServletException {
		try {
			// Abre conexões com o banco.
			EntityFinder.getManager();
			// Encaminha
			chain.doFilter(request, response);
		} finally {
			// Fecha as conexões com o banco.
			EntityFinder.closeManager();
		}
	}
}

No meu EntityFinder tenho esses metodos para abrir e fechar o EntityManager do JPA:

public static EntityManager getManager() {
		EntityManager manager = managerTL.get();
		if (manager != null) return manager;
		EntityManagerFactory factory = Persistence.createEntityManagerFactory(PERS_UNIT_NAME);
		manager = factory.createEntityManager();
		factoryTL.set(factory);
		managerTL.set(manager);
		return manager;
	}

	/**
	 * Closes the EntityManager.
	 */
	public static void closeManager() {
		EntityManager manager = managerTL.get();
		if (manager != null && manager.isOpen()) {
			manager.close();
			managerTL.set(null);
		}
	}

Meu persistence.xml está assim:

<?xml version="1.0" encoding="ISO-8859-1"?>
<persistence version="1.0" xmlns="http://java.sun.com/xml/ns/persistence" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://java.sun.com/xml/ns/persistence http://java.sun.com/xml/ns/persistence/persistence_1_0.xsd">
	<persistence-unit name="persistenceunit">
		<provider>org.hibernate.ejb.HibernatePersistence</provider>
		<class>br.com.ecoder.sgl.entities.Cep</class>
		<class>br.com.ecoder.sgl.entities.Cliente</class>
		<class>br.com.ecoder.sgl.entities.ClienteUsuario</class>
		<class>br.com.ecoder.sgl.entities.Contato</class>
		<class>br.com.ecoder.sgl.entities.CustoReceita</class>
		<class>br.com.ecoder.sgl.entities.Equipamento</class>
		<class>br.com.ecoder.sgl.entities.Perfil</class>
		<class>br.com.ecoder.sgl.entities.PerfilTela</class>
		<class>br.com.ecoder.sgl.entities.ResultadoMonitoramento</class>
		<class>br.com.ecoder.sgl.entities.Site</class>
		<class>br.com.ecoder.sgl.entities.Tela</class>
		<class>br.com.ecoder.sgl.entities.Usuario</class>
		<class>br.com.ecoder.sgl.entities.UsuarioSite</class>
		<properties>
			<property name="hibernate.show_sql" value="false" />
			<property name="hibernate.format_sql" value="true" />
			<property name="hibernate.dialect" value="org.hibernate.dialect.MySQL5InnoDBDialect" />
			<property name="hibernate.connection.driver_class" value="com.mysql.jdbc.Driver" />
			<property name="hibernate.connection.url" value="jdbc:mysql://127.0.0.1:3306/sgl?autoReconnectForPools=true&#38;autoReconnect=true" />
			<property name="hibernate.connection.username" value="root" />
			<property name="hibernate.connection.password" value="javaecoder" />
			<property name="hibernate.hbm2ddl.auto" value="update" />
			<property name="hibernate.cache.use_second_level_cache" value="false" />
			<property name="hibernate.cache.provider_class" value="org.hibernate.cache.NoCacheProvider" />
			<!-- C3PO PROPERTIES -->
			<property name="hibernate.c3p0.acquire_increment" value="1" />
			<property name="hibernate.c3p0.idle_test_period" value="300" />
			<property name="hibernate.c3p0.min_size" value="1" />
			<property name="hibernate.c3p0.max_size" value="3" />
			<property name="hibernate.c3p0.max_statements" value="0" />
			<property name="hibernate.c3p0.timeout" value="60" />
		</properties>
	</persistence-unit>
</persistence>

Apesar de estar usando o Pool de conexoes C3P0, cada resquest novas conexoes sao criadas porém quando fecho o EntityManager elas nao são descartadas. E pior o pool de conexão simplesmente ignora que existem essas conexões dormindo e cria mais… ele deveria usar essas conexões paradas, não é?

Esse problema faz com que o numero maximo de conexoes com o banco seja atingido rapidamente e logo a aplicação cai.

Alguém tem uma pista de como resolver esse erro? O problema é o C3P0 mesmo?

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