在CodeIgniter 3中设置数据库连接超时

We are working with 2 databases, our local database and an external database. But now our external database is down (we're still under development so it's good we came across this issue) and it now tries to connect to the external database for 30 seconds, how can I change the connection timeout of the Database to something like 1 - 2 seconds? I am using Codeigniter with the PDO drivers on my databases. Is there anyone with a clean solution for this problem?We are working with 2 databases, our local data