DB Connections established which fail check-valid-connection-sql do not immediatly close their connection

When a DB connection is attempted to be created where it is configured with new-connection-sql, if the socket/connection succeeds but the new-connection-sql statement fails a connection remains open until GC. In a large volume environment this can lead to many sockets being opened until GC occurs and can thus run into file handle limits.

If a valid TCP connection was established, but the SQL fails, I am suggesting the connection should also be closed at the time of failure, not waiting till GC.