* compare downloads with 'state' = { 'error', 'feed_error' } as well because apparently they sometimes get stored in PostgreSQL / MongoDB too
* temporarily skip "content:(redundant feed)" and "content:(unsupported content type)" downloads because sometimes (for some yet to be known reason) they are
stored in both PostgreSQL (content = '(redundant feed)') and GridFS (content = full XML feed data)
* ditto with "(unsupported content type)"
* exception for download ID = 260024453 because the content in PostgreSQL is "content:" and content in GridFS is a full-blown article