Hi everybody,
I am building a small CMS application with struts and hibernate on tomcat 5.5.17
Since I've discovered that the built in connection pool is not intended for production use, I am trying to switch over to c3p0 and there are my problems. (Using c3p0-0.9.1-pre6)
The connection with c3p0 works only for one database query, after that the connection is closed and I can't use it anymore. If I restart my tomcat, I am able to execute the next query and the connection is closed again and so on. With the built in connection pool (almost) everything works fine.
See the detailed information below:
Hibernate version:
3.1.3
Mapping documents:
<?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>
<!-- Database connection settings -->
<property name="connection.driver_class">
com.mysql.jdbc.Driver
</property>
<property name="connection.url">
<!-- jdbc:hsqldb:hsql://localhost/newsletter -->
jdbc:mysql://localhost:3306/pmcms
</property>
<property name="connection.username">xxxxx</property>
<property name="connection.password">xxxxxx</property>
<!-- C3P0 connection pool -->
<property name="connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
<property name="c3p0.max_size">100</property>
<!-- SQL dialect -->
<property name="dialect">
org.hibernate.dialect.MySQLDialect
</property>
<property name="current_session_context_class">thread</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">false</property>
<!-- Drop and re-create the database schema on startup
<property name="hbm2ddl.auto">create</property> -->
</session-factory>
</hibernate-configuration>
Code between sessionFactory.openSession() and session.close():
Code:
import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.*;
public class HibernateUtil {
public static final SessionFactory sessionFactory;
public static final ThreadLocal session = new ThreadLocal();
static {
try {
// Create the SessionFactory from hibernate.cfg.xml
sessionFactory = new Configuration().configure().buildSessionFactory();
} catch (Throwable ex) {
// Make sure you log the exception, as it might be swallowed
System.err.println("Initial SessionFactory creation failed." + ex);
throw new ExceptionInInitializerError(ex);
}
}
@SuppressWarnings("unchecked")
public static Session currentSession() throws HibernateException {
Session s = (Session) session.get();
// Open a new Session, if this thread has none yet
if (s == null) {
s = sessionFactory.openSession();
// Store it in the ThreadLocal variable
session.set(s);
}
return s;
}
@SuppressWarnings("unchecked")
public static void closeSession() throws HibernateException {
Session s = (Session) session.get();
if (s != null)
s.close();
session.set(null);
}
/**
* @return Returns the sessionFactory.
* @uml.property name="sessionFactory"
*/
public static SessionFactory getSessionFactory() {
return sessionFactory;
}
}
Full stack trace of any exception that occurs:
ERROR - Servlet.service() for servlet action threw exception
org.hibernate.exception.GenericJDBCException: Cannot open connection
at org.hibernate.exception.SQLStateConverter.handledNonSpecificException(SQLStateConverter.java:91)
at org.hibernate.exception.SQLStateConverter.convert(SQLStateConverter.java:79)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:43)
at org.hibernate.exception.JDBCExceptionHelper.convert(JDBCExceptionHelper.java:29)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:327)
at org.hibernate.jdbc.ConnectionManager.getConnection(ConnectionManager.java:118)
at org.hibernate.jdbc.JDBCContext.connection(JDBCContext.java:127)
at org.hibernate.transaction.JDBCTransaction.begin(JDBCTransaction.java:57)
at org.hibernate.impl.SessionImpl.beginTransaction(SessionImpl.java:1307)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:585)
at org.hibernate.context.ThreadLocalSessionContext$TransactionProtectionWrapper.invoke(ThreadLocalSessionContext.java:292)
at $Proxy0.beginTransaction(Unknown Source)
at org.pmedv.cms.daos.AbstractDAO.findAllItems(AbstractDAO.java:42)
at org.pmedv.actions.RegionListAction.execute(RegionListAction.java:30)
at org.apache.struts.action.RequestProcessor.processActionPerform(RequestProcessor.java:419)
at org.apache.struts.action.RequestProcessor.process(RequestProcessor.java:224)
at org.apache.struts.action.ActionServlet.process(ActionServlet.java:1196)
at org.apache.struts.action.ActionServlet.doGet(ActionServlet.java:414)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:689)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:802)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:252)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:173)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:213)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:178)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:126)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:105)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:107)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:148)
at org.apache.coyote.http11.Http11Processor.process(Http11Processor.java:869)
at org.apache.coyote.http11.Http11BaseProtocol$Http11ConnectionHandler.processConnection(Http11BaseProtocol.java:664)
at org.apache.tomcat.util.net.PoolTcpEndpoint.processSocket(PoolTcpEndpoint.java:527)
at org.apache.tomcat.util.net.LeaderFollowerWorkerThread.runIt(LeaderFollowerWorkerThread.java:80)
at org.apache.tomcat.util.threads.ThreadPool$ControlRunnable.run(ThreadPool.java:684)
at java.lang.Thread.run(Thread.java:595)
Caused by: java.sql.SQLException: com.mchange.v2.c3p0.PoolBackedDataSource@1c2dad7 [ connectionPoolDataSource -> com.mchange.v2.c3p0.WrapperConnectionPoolDataSo
urce@d175ff [ acquireIncrement -> 1, acquireRetryAttempts -> 10, acquireRetryDelay -> 1000, autoCommitOnClose -> false, automaticTestTable -> null, breakAfterAc
quireFailure -> false, checkoutTimeout -> 36000, connectionTesterClassName -> com.mchange.v2.c3p0.impl.DefaultConnectionTester, factoryClassLocation -> null, fo
rceIgnoreUnresolvedTransactions -> false, identityToken -> d175ff, idleConnectionTestPeriod -> 0, initialPoolSize -> 1, maxIdleTime -> 0, maxPoolSize -> 100, ma
xStatements -> 0, maxStatementsPerConnection -> 0, minPoolSize -> 1, nestedDataSource -> com.mchange.v2.c3p0.DriverManagerDataSource@20ca8b [ description -> nul
l, driverClass -> null, factoryClassLocation -> null, identityToken -> 20ca8b, jdbcUrl -> jdbc:mysql://localhost:3306/pmcms, properties -> {user=******, passwor
d=******} ], preferredTestQuery -> null, propertyCycle -> 300, testConnectionOnCheckin -> false, testConnectionOnCheckout -> false, usesTraditionalReflectivePro
xies -> false; userOverrides: {} ], dataSourceName -> 1c2dad7, factoryClassLocation -> null, identityToken -> 1c2dad7, numHelperThreads -> 3 ] has been closed()
-- you can no longer use it.
at com.mchange.v2.c3p0.PoolBackedDataSource.assertCpds(PoolBackedDataSource.java:254)
at com.mchange.v2.c3p0.PoolBackedDataSource.getPoolManager(PoolBackedDataSource.java:266)
at com.mchange.v2.c3p0.PoolBackedDataSource.getConnection(PoolBackedDataSource.java:120)
at org.hibernate.connection.C3P0ConnectionProvider.getConnection(C3P0ConnectionProvider.java:35)
at org.hibernate.jdbc.ConnectionManager.openConnection(ConnectionManager.java:324)
... 32 more
Using MySQL 4.1 and 5.0 under WinXP
Any help is really appreciated.
Greetings
Matthias
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