I want to make things failsafe.
If the database server is down, or something goes wrong, TinyTds throws TinyTds::Error. But I can't catch that error. All I want to do is to write log for that and show an error page for user.
I've searched long time but I can't find how.
Problem solved. This is not controller-level issue, and thus, it is obvious that I can't catch an error which is not a controller level.
I've solved with exception_handler gem. With that gem, I can bypass the stock middleware and customize the behavior when I got TinyTds::Error