With a pooled data source, the connections in the pool are not actually closed, they just get returned to the pool. However, when the application is shut down, those connections to the database should be properly and actually closed, which is where the final cleanup comes in. Incidentally, the c3p0 project is pretty much dead … Read more
<!DOCTYPE hibernate-configuration PUBLIC “-//Hibernate/Hibernate Configuration DTD 3.0//EN” “http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd”> <hibernate-configuration> <session-factory> <!– datasource config –> <property name=”connection.url”>jdbc:mysql://localhost:3306/db?useUnicode=true&characterEncoding=UTF-8&autoReconnect=true</property> <property name=”hibernate.dialect”>org.hibernate.dialect.MySQL5InnoDBDialect</property> <property name=”connection.driver_class”>com.mysql.jdbc.Driver</property> <property name=”connection.username”>user</property> <property name=”connection.password”>pass</property> <!– c3p0 config http://www.hibernate.org/214.html –> <property name=”connection.provider_class”>org.hibernate.connection.C3P0ConnectionProvider</property> <property name=”hibernate.c3p0.acquire_increment”>1</property> <property name=”hibernate.c3p0.idle_test_period”>60</property> <property name=”hibernate.c3p0.min_size”>1</property> <property name=”hibernate.c3p0.max_size”>2</property> <property name=”hibernate.c3p0.max_statements”>50</property> <property name=”hibernate.c3p0.timeout”>0</property> <property name=”hibernate.c3p0.acquireRetryAttempts”>1</property> <property name=”hibernate.c3p0.acquireRetryDelay”>250</property> <property name=”hibernate.show_sql”>true</property> <property name=”hibernate.use_sql_comments”>true</property> <property name=”hibernate.transaction.factory_class”>org.hibernate.transaction.JDBCTransactionFactory</property> <property name=”hibernate.current_session_context_class”>thread</property> … Read more
You can choose between 3 different strategies that will impact connection polling. In any case you have to provide an implementation of MultiTenantConnectionProvider. The strategy you choose will of course impact your implementation. General remark about MultiTenantConnectionProvider.getAnyConnection() getAnyConnection() is required by hibernate to collect metadata and setup the SessionFactory. Usually in a multi-tenant architecture you … Read more
This is a configuration I am using which keeps resources to a minimum. Of course you’ll want to tailor your application to use the resources it needs… Reference: http://www.mchange.com/projects/c3p0/index.html testConnectionOnCheckin validates the connection when it is returned to the pool. testConnectionOnCheckOut, although would ensure active connections before use, would be too expensive to do. idleConnectionTestPeriod … Read more
For those who are NOT using a configuration file, just to add the following in the code, before loading the connection pool. Properties p = new Properties(System.getProperties()); p.put(“com.mchange.v2.log.MLog”, “com.mchange.v2.log.FallbackMLog”); p.put(“com.mchange.v2.log.FallbackMLog.DEFAULT_CUTOFF_LEVEL”, “OFF”); // Off or any other level System.setProperties(p);
C3PO and DBCP development have stalled mostly because they are mature. I have seen both of these drivers be able to support hundreds of transactions per second. The Tomcat pool is a reworked & updated DBCP driver. MyBatis 3.0 also contains it’s own pooling implementation which, based on code inspection, seems solid. Finally, there’s BoneCP … Read more
Actually this is probably too late, but the problem is quite simple: hibernate.c3p0.idle_test_periods must not be higher than hibernate.c3p0.timeout or connections closed by the database will not be properly detected. Moreover, the deadlock detection warnings look like some part of your code is not properly returning the connections to the pool (i.e. session.close()) The MysqlIO … Read more
If you would like to keep Lazy Load and you are using Spring Boot, just add the config below in your application.properties: spring.jpa.properties.hibernate.enable_lazy_load_no_trans=true
You’ve done good research. I’d say, go ahead with BoneCP. Some years ago I would have suggested c3p0, but it has currently some open and unresolved issues as well. Too bad, actually. The BoneCP author is by the way also active here at SO.
DBCP is out of date and not production grade. Some time back we conducted an in-house analysis of the two, creating a test fixture which generated load and concurrency against the two to assess their suitability under real life conditions. DBCP consistently generated exceptions into our test application and struggled to reach levels of performance … Read more