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Hibernate c3p0 configuration has no affect

I'm trying to add c3p0 connection pool to our existing hibernate configuration.
But it has no affect and hibernate still uses default pool.
Hibernate Configuration alone is working fine so i am absolutely sure no problem with it.
Wondering if someone here can point my mistake Or suggest how i can debug the problem ?
I do not use Spring framework.
<hibernate-configuration>
<session-factory>
<property name="hibernate.connection.driver_class">com.ibm.db2.jcc.DB2Driver</property>
<property name="hibernate.connection.password">passwd</property>
<property name="hibernate.connection.url">jdbc:db2://server:port/database</property>
<property name="hibernate.connection.username">username</property>
<property name="hibernate.cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<property name="hibernate.connection.autocommit">false</property>
<property name="hibernate.current_session_context_class">thread</property>
<property name="hibernate.default_schema">DB Schema</property>
<property name="hibernate.dialect">org.hibernate.dialect.DB2Dialect</property>
<property name="hibernate.format_sql">false</property>
<property name="hibernate.max_fetch_depth">4</property>
<property name="hibernate.search.autoregister_listeners">false</property>
<property name="hibernate.show_sql">false</property>
<property name="hibernate.connection.isolation">1</property>
<property name="hibernate.jdbc.batch_size">50</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.timeout">3000</property>
<property name="hibernate.c3p0.max_statements">50</property>
<property name="hibernate.c3p0.idle_test_period">900</property>
<mapping resource="table.hbm.xml" />
</session-factory>
</hibernate-configuration>
Here are the jars i have:
hibernate3.jar
hibernate-c3p0-3.5.0-Final.jar
Statements from the logs:
hibernate.cfg.Environment - Hibernate 3.5.0-Final
INFO ManagerConnectionProvider - Using Hibernate built-in connection pool (not for production use!)
INFO ManagerConnectionProvider - Hibernate connection pool size: 20

Try configuring a connection provider class from c3p0.
<property name="hibernate.connection.provider_class">org.hibernate.connection.C3P0ConnectionProvider</property>
Also, it's better to add the hibernate configuration doctype, which will help in finding any typos.
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
UPDATE
You need to include the mchange library in your classpath. This link might helpful to you.

Prefix for hibernate connection configurations?

Does anybody know about the hibernate configurations file (hibernate.cfg.xml), what are the "connection" properties - without the "hibernate" prefix - used for?
I mean, why do those properties (such as connection.url, connection.usermame...) exist?
<hibernate-configuration>
<session-factory>
<property name="connection.driver_class">org.postgresql.Driver</property>
...
<property name="connection.url">SOME_URL</property>
<property name="hibernate.connection.url">SOME_URL</property>
<property name="connection.username">SOME_USER</property>
<property name="hibernate.connection.username">SOME_USER</property>
...
Why can I use the both connection.url and hibernate.connection.url ?
ANSWER:
Ok, I believe those properties (without the hibernate. prefix) exist just for backward compatibility with configuration files of older hibernate versions.
Thanks.

The hibernate.connection.url is use to connect the database url following is the configuration setting for hibernate . Hope It will help you.
<property name="hibernate.dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="hibernate.connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="hibernate.connection.url">jdbc:mysql://localhost:3306/youdb</property>
<property name="hibernate.connection.username">user</property>
<property name="hibernate.connection.password">password</property>
<property name="hibernate.hbm2ddl.auto">update</property>
<property name="hibernate.show_sql">true</property>
<mapping resource="emp/dto/Employee.hbm.xml"/>

Hibernate Criteria.setMaxResults() fails on Oracle 11g

When using hibernate to retrieve data from Oracle 11g DB using either org.hibernate.dialect.Oracle10gDialect or org.hibernate.dialect.OracleDialect
I get the following:
org.hibernate.exception.SQLGrammarException: could not execute query
Caused by: java.sql.SQLSyntaxErrorException: ORA-00923: FROM keyword not found where expected
Looking in the log we can see the query:
select top ? this_.LI_ILN as LI1_8_0_, this_.COUNTRY_CODE ...
Obviously, the DB doesn't recognize the keyword and this is where the problem lies, because in Oracle pagination can only be done by using ROWNUM, a thing which Hibernate should know.
The hibernate configuration looks as follows:
<hibernate-configuration>
<session-factory name="HibernateSessionFactory">
<property name="hibernate.bytecode.use_reflection_optimizer">false</property>
<property name="hibernate.connection.driver_class">oracle.jdbc.OracleDriver</property>
<property name="hibernate.connection.password">...</property>
<property name="hibernate.connection.url">...</property>
<property name="hibernate.connection.username">...</property>
<property name="hibernate.default_schema">...</property>
<property name="hibernate.dialect">org.hibernate.dialect.OracleDialect</property>
<property name="hibernate.search.autoregister_listeners">false</property>
<property name="hibernate.show_sql">true</property>
<property name="hibernate.hbm2ddl.auto">validate</property>
<property name="hibernate.transaction.auto_close_session">false</property>
<mapping resource="HB_Mappings/Supplier.hbm.xml" />
</session-factory>
The query is done like so:
Criteria crit = sessionFactory.getCurrentSession().createCriteria(Supplier.class);
crit.setFirstResult(50 * pageIndex);
crit.setMaxResults(50);
List<Supplier> list = crit.list();
Any help is appreciated.
Solved:
Forgot to mention that I am using spring in which the applicationContext.xml looks like:
<bean id="sessionFactory" class="org.springframework.orm.hibernate3.LocalSessionFactoryBean">
<property name="dataSource" ref="dataSource" />
<property name="configLocation">
<value>classpath:HB_Mappings/hibernate.cfg.xml</value>
</property>
<property name="hibernateProperties">
<value>hibernate.dialect=org.hibernate.dialect.HSQLDialect</value>
</property>
</bean>
It overwrote the hibernate.cfg.xml's property...
Note to self: go easy on copy-paste

OracleDialect is deprecated, see here:
http://docs.jboss.org/hibernate/core/4.1/javadocs/org/hibernate/dialect/OracleDialect.html
Use the Oracle10gDialect instead: http://docs.jboss.org/hibernate/core/4.1/javadocs/org/hibernate/dialect/Oracle10gDialect.html
Also Check this out, and make sure that you are using the newest Oracle JDBC driver.
https://web.archive.org/web/20130204044852/https://community.jboss.org/wiki/SupportedDatabases2

Hibernate and too many connections

I am working on web-project with Hibernate ans Spring MVC.
My hibernate configuration is:
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost/xxx</property>
<property name="connection.username">xxx</property>
<property name="connection.password">xxx</property>
<property name="hibernate.c3p0.min_size">5</property>
<property name="hibernate.c3p0.max_size">20</property>
<property name="hibernate.c3p0.timeout">1800</property>\<property name="hibernate.c3p0.max_statements">50</property>
<property name="dialect">org.hibernate.dialect.MySQL5Dialect</property>
<property name="connection.useUnicode">true</property>
<property name="connection.characterEncoding">UTF-8</property>
<property name="current_session_context_class">thread</property>
<property name="show_sql">true</property>
The hibernate sessions are closing in service-classes destructors (these service-classes have DAO objects). But after publishing at production server I've got too many connections exception from mysql.Every server call, the mysql connection was opened. When the connections amount become 101 - db failed. I think that destructors had not time enought for executes so the connections were opened all the time.
Then, I rebuilded the structure. Now, the Spring controllers call the service-class function, that releases the session mannualy. But it doesn't help: the connections are still opened and now I can not use LAZY-collections in views because the session already closed.
How can I solve that problem? What is the usual approach here?
Thank you.

How to avoid stale MySQL/Hibernate connections (MySQLNonTransientConnectionException)

I have a Java webapp using Hibernate and MySQL. If the site isn't used for a few days, the MySQL connection goes stale, and I am met with the following exception:
com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Connection.close() has already been called. Invalid operation in this state.
From experience using raw JDBC it is possible to configure the connection to attempt to recover from errors or stale connections, but I don't know how to do this using Hibernate. I am not explicitly calling close() anywhere (but I am betting Hibernate does somewhere deep down in its guts).
Does anybody know what I should do?

What connection pool are you using?
The Hibernate suggestion is not to use the built-in pooling, but use the application server datasource or something like Commons DBCP or C3PO.

I had that problem. Using connection pooling (c3p0) made it go away. It is also a good idea in general to use some connection pooling.

Thanks for the advice. For posterity's sake, I changed the hibernate.cfg.xml from the following:
<property name="connection.url">jdbc:mysql://localhost/FooDB</property>
<property name="connection.username">root</property>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="connection.password">secret</property>
<property name="transaction.factory_class">org.hibernate.transaction.JDBCTransactionFactory</property>
... to the following:
<property name="connection.datasource">java:/comp/env/jdbc/FooDB</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
This also required adding a standard 'context' entry in my web app's context.xml:
<Resource name="jdbc/FooDB"
auth="Container"
type="javax.sql.DataSource"
maxActive="100"
maxIdle="30"
maxWait="10000"
username="root"
password="secret"
driverClassName="com.mysql.jdbc.Driver"
url="jdbc:mysql://localhost:3306/ss?autoReconnect=true" />

We had a similar problem of hibernate mysql connection getting timed out.
So we tried C3P0, with the following configuration:
<property name=c3p0.acquire_increment>1</property>
<property name=c3p0.idle_test_period>3600</property>
<property name=c3p0.max_statements>0</property>
<property name=c3p0.min_size>1</property>
<property name=c3p0.timeout>3605</property>
<property name=hibernate.c3p0.preferredTestQuery>select 1;</property>
Hibernate connection_pool size was set to 1.
This made the timeout problem go away. But we started facing another problem. Long waits.
We have a service (servlet running on jboss), which receives something like 5-6 requests per second. Every request needs to connect to mysql through hibernate. Most of our requests do selects, with an insert/update every 5th-6th request. Normally the request serve time for us is 2-3ms for select and 40-50ms for insert/update. But, after using the above C3P0 configuration, we saw that every request completing after an update was taking almost 4-5 minutes! From our logs, it seemed that randomly a select request will get stuck and will be able to complete only after an update request was received and served.
Above problem goes away if we remove the C3P0 config. Can somebody suggest what we could be doing wrong?
Here is the complete hibernate config for reference:
<?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>
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://xxx.xxx.xxx</property>
<property name="connection.username">xxx</property>
<property name="connection.password">xxx</property>
<property name="connection.pool_size">1</property>
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<property name="current_session_context_class">thread</property>
<property name="hibernate.cache.use_query_cache">false</property>
<property name="hibernate.cache.use_second_level_cache">false</property>
<property name="show_sql">true</property>
<!-- Transaction isolation 2 = READ_COMMITTED -->
<property name="connection.isolation">2</property>
<property name="connection.autocommit">true</property>
<!-- configuration pool via c3p0-->
<property name="c3p0.acquire_increment">1</property>
<property name="c3p0.idle_test_period">3600</property> <!-- seconds -->
<property name="c3p0.max_size">1</property>
<property name="c3p0.max_statements">0</property>
<property name="c3p0.min_size">1</property>
<property name="c3p0.timeout">3605</property> <!-- seconds -->
<property name="hibernate.c3p0.preferredTestQuery">select 1;</property>
</session-factory>
</hibernate-configuration>

<property name="c3p0.acquire_increment">1</property>
<property name="c3p0.idle_test_period">120</property> <!-- seconds -->
<property name="c3p0.max_size">100</property>
<property name="c3p0.max_statements">0</property>
<property name="c3p0.min_size">10</property>
<property name="c3p0.timeout">180</property> <!-- seconds -->
override these settings on your config file. It ll helps to you.