如何在 Hibernate 中禁用连接池

Question

I have a web application that currently uses c3p0 and Hibernate to connect to a Firebird 1.5 database.

I am facing a problem from time to time where the database just stops responding, even trying to manually restart the service doesn't have any effect, and it doesn't generate any logs, so I have to manually reboot the machine to get it working again.

I think that maybe Firebird hangs when the pool tries to acquire a specific number of connections or something like that. So, I need to test my app without connection pooling, to check if this is or is not the problem.

I can't simply remove c3p0 configs from persistence because this way Hibernate would use its own integrated connection pool. So how to do it?

Answer 1

The most flexible solution is to use an explicit DataSource , instead of configuring the connection pooling through Hibernate. One option to configure a non-pooling DataSource is by using DriverManagerDataSource :

@Override
protected Properties getProperties() {
    Properties properties = new Properties();
    properties.put("hibernate.dialect", "org.hibernate.dialect.HSQLDialect");
    //log settings
    properties.put("hibernate.hbm2ddl.auto", "update");
    //data source settings
    properties.put("hibernate.connection.datasource", newDataSource());
    return properties;
}

protected ProxyDataSource newDataSource() {
    DriverManagerDataSource actualDataSource = new DriverManagerDataSource();
    actualDataSource.setUrl("jdbc:hsqldb:mem:test");
    actualDataSource.setUsername("sa");
    actualDataSource.setPassword("");
    ProxyDataSource proxyDataSource = new ProxyDataSource();
    proxyDataSource.setDataSource(actualDataSource);
    proxyDataSource.setListener(new SLF4JQueryLoggingListener());
    return proxyDataSource;
}

This way you can choose a pooling or a non-pooling DataSource .

To get a better understanding of you connection pooling resources usage, you can configure FlexyPool to collect metrics for:

• concurrent connections
• concurrent connection requests
• data source connection acquiring time
• connection lease time
• maximum pool size
• total connection acquiring time
• overflow pool size
• retries attempts

Answer 2

I found documentation for hibernate 3.3 and 4.3 that says:

Just replace the hibernate.connection.pool_size property with connection pool specific settings. This will turn off Hibernate's internal pool.

Hibernate will use its org.hibernate.connection.C3P0ConnectionProvider for connection pooling if you set hibernate.c3p0.* properties

So remove hibernate.connection.pool_size and any hibernate.c3p0... properties from configuration, than connection pooling is disabled.

Answer 3

Adding to Vlad's answer:

If somebody still faces this:

• Be sure to remove " hibernate-c3p0 " from your classpath, if exists, since this will automatically enable MChange c3p0 connection pool.

• Another option that, you can close the connection manually when closing the entity manager:

   .... SessionImpl ses = (SessionImpl) session; close(ses.connection()); try { session.close(); } catch (Exception e) { logger.error(e); }........

Note : the above manual closing will work with the default pool of hibernate, not hibernate default one.

Good Luck