MySQL connections not closing

Question

I have a web application running on Tomcat7 that connects to MySQL 5.5.

I have two servers running the identical code:

• Ubuntu

• Red Hat

The Ubuntu one runs fine maintaining a steady 8-16 connections, but the Red Hat one leaks connections and the connection count grows, never going down. The server eventually resets ~152 connections.

The code to close the connection is getting called:

try {
    conn.close();           
} catch (SQLException e) {
    exceptionController.logException(this.getClass().getSimpleName(), "finalize Db", e.getMessage(), false);
}finally{
    conn = null;
}

All connections to MySQL are from this app.

Why the difference in behavior? Are there configuration settings that I should be considering - like closing sleeping connections setting ?

Ubuntu Server Status:

Red Hat Server Status:

Partial screen of the connection list:

I found this post , which appears to have slowed o/s connections, but they still are creeping up.

EDIT

Research is pointing to the connections not closing properly. Why would the connections close in one environment but not another?

I have edited my.cnf with the following setting:

wait_timeout=30

However, client connections are sleeping and never getting killed. The server has been restarted with the new setting in place.

What am I not understanding?

Answer 1

I found the solution. XP on SO Database Administrators .

RedHat has its own mysql folders:

[root@localhost ~]# locate my.cnf
/etc/my.cnf
/opt/rh/mysql55/root/etc/my.cnf

It was a configuration issue and my config file was not being used!