Connection drop problem with Hibernate-mysql-c3p0
- by user344788
hi all,
This is an issue which I have seen all across the web. I will bring it up again as till now I don't have a fix for the same.
I am using hibernate 3. mysql 5 and latest c3p0 jar. I am getting a broken pipe exception. Following is my hibernate.cfg file.
com.mysql.jdbc.Driver
org.hibernate.dialect.MySQLDialect
<property name="hibernate.show_sql">true</property>
<property name="hibernate.use_sql_comments">true</property>
<property name="hibernate.current_session_context_class">thread</property>
<property name="connection.autoReconnect">true</property>
<property name="connection.autoReconnectForPools">true</property>
<property name="connection.is-connection-validation-required">true</property>
<!--<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="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider
</property>
<property name="hibernate.c3p0.acquireRetryAttempts">30</property>
<property name="hibernate.c3p0.acquireIncrement">5</property>
<property name="hibernate.c3p0.automaticTestTable">C3P0TestTable</property>
<property name="hibernate.c3p0.idleConnectionTestPeriod">36000</property>
<property name="hibernate.c3p0.initialPoolSize">20</property>
<property name="hibernate.c3p0.maxPoolSize">100</property>
<property name="hibernate.c3p0.maxIdleTime">1200</property>
<property name="hibernate.c3p0.maxStatements">50</property>
<property name="hibernate.c3p0.minPoolSize">10</property>-->
My connection pooling is occurring fine. During the day it is fine , but once i keep it idle over the night ,next day I find it giving me broken connection error.
public class HibernateUtil {
private static Logger log = Logger.getLogger(HibernateUtil.class);
//private static Log log = LogFactory.getLog(HibernateUtil.class);
private static Configuration configuration;
private static SessionFactory sessionFactory;
static {
// Create the initial SessionFactory from the default configuration files
try {
log.debug("Initializing Hibernate");
// Read hibernate.properties, if present
configuration = new Configuration();
// Use annotations: configuration = new AnnotationConfiguration();
// Read hibernate.cfg.xml (has to be present)
configuration.configure();
// Build and store (either in JNDI or static variable)
rebuildSessionFactory(configuration);
log.debug("Hibernate initialized, call HibernateUtil.getSessionFactory()");
} catch (Throwable ex) {
// We have to catch Throwable, otherwise we will miss
// NoClassDefFoundError and other subclasses of Error
log.error("Building SessionFactory failed.", ex);
throw new ExceptionInInitializerError(ex);
}
}
/**
* Returns the Hibernate configuration that was used to build the SessionFactory.
*
* @return Configuration
*/
public static Configuration getConfiguration() {
return configuration;
}
/**
* Returns the global SessionFactory either from a static variable or a JNDI lookup.
*
* @return SessionFactory
*/
public static SessionFactory getSessionFactory() {
String sfName = configuration.getProperty(Environment.SESSION_FACTORY_NAME);
System.out.println("Current s name is "+sfName);
if ( sfName != null) {
System.out.println("Looking up SessionFactory in JNDI");
log.debug("Looking up SessionFactory in JNDI");
try {
System.out.println("Returning new sssion factory");
return (SessionFactory) new InitialContext().lookup(sfName);
} catch (NamingException ex) {
throw new RuntimeException(ex);
}
} else if (sessionFactory == null) {
System.out.println("calling rebuild session factory now");
rebuildSessionFactory();
}
return sessionFactory;
}
/**
* Closes the current SessionFactory and releases all resources.
* <p>
* The only other method that can be called on HibernateUtil
* after this one is rebuildSessionFactory(Configuration).
*/
public static void shutdown() {
log.debug("Shutting down Hibernate");
// Close caches and connection pools
getSessionFactory().close();
// Clear static variables
sessionFactory = null;
}
/**
* Rebuild the SessionFactory with the static Configuration.
* <p>
* Note that this method should only be used with static SessionFactory
* management, not with JNDI or any other external registry. This method also closes
* the old static variable SessionFactory before, if it is still open.
*/
public static void rebuildSessionFactory() {
log.debug("Using current Configuration to rebuild SessionFactory");
rebuildSessionFactory(configuration);
}
/**
* Rebuild the SessionFactory with the given Hibernate Configuration.
* <p>
* HibernateUtil does not configure() the given Configuration object,
* it directly calls buildSessionFactory(). This method also closes
* the old static variable SessionFactory before, if it is still open.
*
* @param cfg
*/
public static void rebuildSessionFactory(Configuration cfg) {
log.debug("Rebuilding the SessionFactory from given Configuration");
if (sessionFactory != null && !sessionFactory.isClosed())
sessionFactory.close();
if (cfg.getProperty(Environment.SESSION_FACTORY_NAME) != null) {
log.debug("Managing SessionFactory in JNDI");
cfg.buildSessionFactory();
} else {
log.debug("Holding SessionFactory in static variable");
sessionFactory = cfg.buildSessionFactory();
}
configuration = cfg;
}
}
Above is my code for the session factory. And I have only select operations .
And below is the method which is used most often to execute my select queries. One tricky thing which I am not understanding is in my findById method i am using this line of code getSession().beginTransaction(); without which it gives me an error saying that this cannot happpen without a transaction. But nowhere I am closing this transaction. And thers no method to close a transaction apart from commit or rollback (as far as i know) which are not applicable for select statements.
public T findById(ID id, boolean lock) throws HibernateException, DAOException {
log.debug("findNyId invoked with ID ="+id+"and lock ="+lock);
T entity;
getSession().beginTransaction();
if (lock)
entity = (T) getSession().load(getPersistentClass(), id, LockMode.UPGRADE);
else
entity = (T) getSession().load(getPersistentClass(), id);
return entity;
}
Can anyone please suggest what can I do ? I have tried out almost every solution available via googling, on stackoverlow or on hibernate forums with no avail. (And increasing wait_timeout on mysql is not a valid option in my case).
