out of interest (and I know nothing about such things) why can't you start at a more sensible time?
Because when I'm doing the update the product database I use on some of my websites doesn't work, so I do it when not many people are online.
I should have designed the system properly so it doesn't have any downtime, but when I first started I only had a few thousand products in it, now it's over 5 million and takes a long time to index everything.