What will happens if an controller handler occurs an exception

[shar0]

If other handler thread is executing SQL writing task, will this exception crash entire application?
How to avoid this? Just like use SQL transaction?

[an-tao]

Any exception in the IO thread that escapes from the user handler will be caught by drogon and handled in a global function. Users can use the setExceptionHandler method of drogon::app() to customize the handling process.