This morning I had a Mikrotik CCR1016 where I had to change the router ID, which caused all the sessions to reset. The following is a screenshot of the time it took to re-learn all of the peers. Obviously, the smaller prefixes were learned pretty quickly. It took about 10 minutes to learn two full IPv4 route tables and about 5 minutes to learn the IPv6 routing tables.
This is why I always get full routes plus a default from the upstream when it warrants full routes. This way I can have slow convergence time like this and still have traffic flowing.j2networks family of sites