Until we see evidence that our DB indeed clutters up in lots of unused URIs and whatnot (after some DeleteEvents), then I don't think the added complexity is worth it.
A more pressing issue is to delete unused URIs after a DeleteEvents because of privacy reasons - it's fine that we delete all events about http://example.com/explicit_content, but we still have the URI in the 'uri' table. However, we have to make sure that the URI is not reffed by any other existing event before pruning it. But this seems to be another bug, although heavily related to this issue.
Until we see evidence that our DB indeed clutters up in lots of unused URIs and whatnot (after some DeleteEvents), then I don't think the added complexity is worth it.
A more pressing issue is to delete unused URIs after a DeleteEvents because of privacy reasons - it's fine that we delete all events about http:// example. com/explicit_ content, but we still have the URI in the 'uri' table. However, we have to make sure that the URI is not reffed by any other existing event before pruning it. But this seems to be another bug, although heavily related to this issue.