I read your log on http://pastebin.ca/2958608 again and saw that (why didn't I see it before?!) that it was even _after_ file_redirection (how did I ever even think it was the 'file' table????).

Because it says: "Updating urlhash fields in file_redirection table...DONE. Resuming core schema upgrade..." it is _done_ with file_redirection.

So the next step in alphabetical order would be file_thumbnail which has the _filename_ field limited to 191 characters. And afaik we never use the `filename` field for indexing so it might as well just be set to a text type. Let me try that.