Hibernate in JSF Social Application runs out of connections - mysql

Question

I'm currently writing a JSF based Social Application. I'm also using Hibernate to persist, update and merge data. But at some point my application stops responding with following error.
Caused by: com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: "Too many connections"
at sun.reflect.GeneratedConstructorAccessor848.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.Util.getInstance(Util.java:386)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:1015)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:989)
at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:975)
at com.mysql.jdbc.MysqlIO.doHandshake(MysqlIO.java:1114)
at com.mysql.jdbc.ConnectionImpl.coreConnect(ConnectionImpl.java:2502)
at com.mysql.jdbc.ConnectionImpl.connectOneTryOnly(ConnectionImpl.java:2535)
at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2320)
at com.mysql.jdbc.ConnectionImpl.<init>(ConnectionImpl.java:834)
at com.mysql.jdbc.JDBC4Connection.<init>(JDBC4Connection.java:46)
at sun.reflect.GeneratedConstructorAccessor822.newInstance(Unknown Source)
at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:45)
at java.lang.reflect.Constructor.newInstance(Constructor.java:422)
at com.mysql.jdbc.Util.handleNewInstance(Util.java:411)
at com.mysql.jdbc.ConnectionImpl.getInstance(ConnectionImpl.java:416)
at com.mysql.jdbc.NonRegisteringDriver.connect(NonRegisteringDriver.java:347)
at org.hibernate.engine.jdbc.connections.internal.DriverConnectionCreator.makeConnection(DriverConnectionCreator.java:55)
... 127 more
the java code that executes transactions is here:
public class TransactionManager {
private static SessionFactory sessionFactory;
private static ServiceRegistry serviceRegistry;
public TransactionManager() {
}
public IEntity validateUser(String userName, String userPassword) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
String hql = "FROM AccountEntity";
Query query = session.createQuery(hql);
#SuppressWarnings("unchecked")
List<IAccountEntity> results = query.list();
for (IAccountEntity user : results) {
if (user.getUserName().equals(userName) && user.getPassword().equals(userPassword)) {
session.close();
sessionFactory.close();
return user;
}
}
session.close();
sessionFactory.close();
return null;
}
public IEntity retrieveUserByName(String userName) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
String hql = "FROM AccountEntity A WHERE A.userName = '" + userName + "'";
Query query = session.createQuery(hql);
#SuppressWarnings("unchecked")
List<IAccountEntity> results = query.list();
session.close();
sessionFactory.close();
if (!results.isEmpty()) {
return results.get(0);
}
return null;
}
public IEntity retrievePageByName(String pageName) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
String hql = "FROM PageEntity A WHERE A.pageName = '" + pageName + "'";
Query query = session.createQuery(hql);
#SuppressWarnings("unchecked")
List<IAccountEntity> results = query.list();
session.close();
sessionFactory.close();
if (!results.isEmpty()) {
return results.get(0);
}
return null;
}
public Map<IEntity, Integer> save(Object... objects) {
Map<IEntity, Integer> savedMap = new HashMap<IEntity, Integer>();
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
for (Object object : objects) {
session.save(object);
savedMap.put((IEntity) object, ((IEntity) object).getId());
}
session.getTransaction().commit();
session.close();
sessionFactory.close();
return savedMap;
}
public void merge(IEntity entity) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.update(entity);
session.getTransaction().commit();
session.close();
sessionFactory.close();
}
// SELECT * FROM `commententity` WHERE id BETWEEN 3 and 5 and
// accountEntityId = 1 ORDER BY id DESC
// SELECT * FROM `commententity` WHERE targetAccountEntity_id='1' ORDER BY
// id LIMIT 5 OFFSET 0
// FROM dao.CommentEntity D WHERE targetAccountEntity_id='1' ORDER BY D.id
// DESC
public List<IEntity> retrievePaginatedById(String classType, String targetId, String status, int id, int offset,
int limit, boolean forContactRequestNotification) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
String hql = null;
if (forContactRequestNotification) {
hql = "FROM " + classType + " D WHERE " + targetId + "=" + "'" + id + "' AND D.status = '" + status
+ "' ORDER BY D.id DESC";
} else {
hql = "FROM " + classType + " D WHERE " + targetId + "=" + "'" + id + "'" + " ORDER BY D.id DESC";
}
Query query = session.createQuery(hql).setFirstResult(offset).setMaxResults(limit);
#SuppressWarnings("unchecked")
List<IEntity> results = query.list();
session.close();
sessionFactory.close();
return results;
}
public List<IEntity> retrieveMultipleById(String classType, String targetId, String status, int id,
boolean forContactRequestNotification) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
String hql = null;
if (forContactRequestNotification) {
// SONDERFALL
hql = "FROM " + classType + " D WHERE D.status = '" + status + "' and " + targetId + "= " + id;
} else {
hql = "FROM " + classType + " D WHERE " + targetId + "= " + id;
}
Query query = session.createQuery(hql);
#SuppressWarnings("unchecked")
List<IEntity> results = query.list();
session.close();
sessionFactory.close();
return results;
}
public IEntity retrieveById(Class<?> c, int id) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
IEntity entity = (IEntity) session.get(c, id);
session.close();
sessionFactory.close();
return entity;
}
public void delete(IEntity obj) {
SessionFactory sessionFactory = createSessionFactory();
Session session = sessionFactory.openSession();
session.beginTransaction();
session.delete(obj);
session.getTransaction().commit();
session.close();
sessionFactory.close();
}
public static SessionFactory createSessionFactory() {
Configuration configuration = new Configuration();
configuration.configure();
serviceRegistry = new StandardServiceRegistryBuilder().applySettings(configuration.getProperties()).build();
sessionFactory = configuration.buildSessionFactory(serviceRegistry);
return sessionFactory;
}
}
and this is a sample image of how a profile looks like, I'm supporting lazy loading to avoid big transactions.
I just dont get what am I doing so wrong here. I read somewhere I have to close every connection. But that doesn't seem to solve the problem.

Answer 1

Please increase the mysql connection size.
Go to mysql console and run below
SHOW VARIABLES LIKE "max_connections";
You will see the maximum allowed connections. You can change them using
SET GLOBAL max_connections = 200;
Restart mysql server, and it should be working fine.