Database connection timeout

Question

I have read so many articles on the Internet about this problem but none seem to have a clear solution. Please could someone give me a definite answer as to why I am getting database timeouts. The app is a GWT app that is being hosted on a Tomcat 5.5 server. I use spring and the session factory is created in the applicationContext.xml as follows

<bean id="sessionFactory"
      class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
    <property name="hibernateProperties">
        <props>
            <prop key="hibernate.dialect">${connection.dialect}</prop>
            <prop key="hibernate.connection.username">${connection.username}</prop>
            <prop key="hibernate.connection.password">${connection.password}</prop>
            <prop key="hibernate.connection.url">${connection.url}</prop>
            <prop key="hibernate.connection.driver_class">${connection.driver.class}</prop>
            <prop key="hibernate.show_sql">${show.sql}</prop>
            <prop key="hibernate.hbm2ddl.auto">update</prop>
            <prop key="hibernate.c3p0.min_size">5</prop>
            <prop key="hibernate.c3p0.max_size">20</prop>
            <prop key="hibernate.c3p0.timeout">1800</prop>
            <prop key="hibernate.c3p0.max_statements">50</prop>
            <prop key="hibernate.c3p0.idle_test_period">300</prop>
        </props>
    </property>
    <property name="annotatedClasses">
        <list>
            <value>za.co.xxxx.traintrack.server.model.Answer</value>
            <value>za.co.xxxx.traintrack.server.model.Company</value>
            <value>za.co.xxxx.traintrack.server.model.CompanyRegion</value>
            <value>za.co.xxxx.traintrack.server.model.Merchant</value>
            <value>za.co.xxxx.traintrack.server.model.Module</value>
            <value>za.co.xxxx.traintrack.server.model.Question</value>
            <value>za.co.xxxx.traintrack.server.model.User</value>
            <value>za.co.xxxx.traintrack.server.model.CompletedModule</value>
        </list>
    </property>
</bean>

<bean id="dao" class="za.co.xxxx.traintrack.server.DAO">
    <property name="sessionFactory" ref="sessionFactory"/>
    <property name="adminUsername" value="${admin.user.name}"/>
    <property name="adminPassword" value="${admin.user.password}"/>
    <property name="godUsername" value="${god.user.name}"/>
    <property name="godPassword" value="${god.user.password}"/>
</bean>

All works fine untile the next day:

INFO   | jvm 1    | 2010/06/15 14:42:27 | 2010-06-15 18:42:27,804 WARN 
[JDBCExceptionReporter] : SQL Error: 0, SQLState: 08S01
INFO   | jvm 1    | 2010/06/15 14:42:27 | 2010-06-15 18:42:27,821 ERROR 
[JDBCExceptionReporter] : The last packet successfully received from the server 
was 38729 seconds ago.The last packet sent successfully to the server was 38729
seconds ago, which  is longer than the server configured value of 'wait_timeout'.
You should consider either expiring and/or testing connection validity before 
use in your application, increasing the server configured values for client
timeouts, or using the Connector/J connection property 'autoReconnect=true' to
avoid this problem.
INFO   | jvm 1    | 2010/06/15 14:42:27 | Jun 15, 2010 6:42:27 PM 
org.apache.catalina.core.ApplicationContext log
INFO   | jvm 1    | 2010/06/15 14:42:27 | SEVERE: Exception while dispatching
incoming RPC call

I have read so many different things (none of which worked), please help

Answer 1

Romain, I do not have a hibernate.cfg.xml (all done in applicationContext.XML)

c3p0.properties

c3p0.testConnectionOnCheckout=true

applicationContext.xml

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xmlns:tx="http://www.springframework.org/schema/tx"
       xsi:schemaLocation="
           http://www.springframework.org/schema/context
           http://www.springframework.org/schema/context/spring-context-2.5.xsd
           http://www.springframework.org/schema/beans
           http://www.springframework.org/schema/beans/spring-beans-2.0.xsd
           http://www.springframework.org/schema/tx
           http://www.springframework.org/schema/tx/spring-tx-2.0.xsd
           ">

    <context:annotation-config/>

    <context:component-scan base-package="za.co.cmsoftware.traintrack.server"/>

    <!-- Application properties -->
    <bean id="propertyConfigurer" class="org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>file:${user.dir}/@propertiesFile@</value>
            </list>
        </property>
    </bean>

    <bean id="sessionFactory"
          class="org.springframework.orm.hibernate3.annotation.AnnotationSessionFactoryBean">
        <property name="hibernateProperties">
            <props>
                <prop key="hibernate.dialect">${connection.dialect}</prop>
                <prop key="hibernate.connection.username">${connection.username}</prop>
                <prop key="hibernate.connection.password">${connection.password}</prop>
                <prop key="hibernate.connection.url">${connection.url}</prop>
                <prop key="hibernate.connection.driver_class">${connection.driver.class}</prop>
                <prop key="hibernate.show_sql">${show.sql}</prop>
                <prop key="hibernate.hbm2ddl.auto">update</prop>
                <prop key="hibernate.c3p0.min_size">5</prop>
                <prop key="hibernate.c3p0.max_size">20</prop>
                <prop key="hibernate.c3p0.timeout">1800</prop>
                <prop key="hibernate.c3p0.max_statements">50</prop>
                <prop key="hibernate.c3p0.idle_test_period">300</prop>
                <prop key="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</prop>
            </props>
        </property>
        <property name="annotatedClasses">
            <list>
                <value>za.co.xxxx.traintrack.server.model.Answer</value>
                <value>za.co.xxxx.traintrack.server.model.Company</value>
                <value>za.co.xxxx.traintrack.server.model.CompanyRegion</value>
                <value>za.co.xxxx.traintrack.server.model.Merchant</value>
                <value>za.co.xxxx.traintrack.server.model.Module</value>
                <value>za.co.xxxx.traintrack.server.model.Question</value>
                <value>za.co.xxxx.traintrack.server.model.User</value>
                <value>za.co.xxxx.traintrack.server.model.CompletedModule</value>
            </list>
        </property>
    </bean>

    <bean id="dao" class="za.co.xxxx.traintrack.server.DAO">
        <property name="sessionFactory" ref="sessionFactory"/>
        <property name="adminUsername" value="${admin.user.name}"/>
        <property name="adminPassword" value="${admin.user.password}"/>
        <property name="godUsername" value="${god.user.name}"/>
        <property name="godPassword" value="${god.user.password}"/>
    </bean>

    <bean id="transactionManager"
          class="org.springframework.orm.hibernate3.HibernateTransactionManager">
        <property name="sessionFactory">
            <ref local="sessionFactory"/>
        </property>
    </bean>

    <!-- enable the configuration of transactional behavior based on annotations -->
    <tx:annotation-driven transaction-manager="transactionManager"/>

</beans>

Answer 2

Look at this link http://www.databasesandlife.com/automatic-reconnect-from-hibernate-to-mysql/

 In “hibernate.cfg.xml”:

<!-- hibernate.cfg.xml -->
<property name="c3p0.min_size">5</property>
<property name="c3p0.max_size">20</property>
<property name="c3p0.timeout">1800</property>
<property name="c3p0.max_statements">50</property>
<property name="connection.provider_class">
   org.hibernate.connection.C3P0ConnectionProvider</property>
<!-- no "connection.pool_size" entry! -->

Then create a file “c3p0.properties” which must be in the root of the classpath (i.e. no way to override it for particular parts of the application):

# c3p0.properties
c3p0.testConnectionOnCheckout=true