asterisk users - Jan 2010 - Which to choose? Realtime extension OR Static extension with MYSQL command

hi,all

one thing confused me these days. i don't know which method to choose,
and don't know which one is better perfoermance than another when in
production system.

i can save dialplan in the extension table , i also can write dialplan
in extension.conf with MYSQL commmand to fetch data from database.

but which one is better?

Could you shed some light to me?

Any suggestion will be appreciated.

Thank you!

-- 
Best regards,
Sucan