# Statuses should have only one preview card at most, even if that's not the database
# constraint we will end up with
duplicate_ids=select_all('SELECT status_id FROM preview_cards_statuses GROUP BY status_id HAVING count(*) > 1;').rows
duplicate_ids.each_slice(1000)do|ids|
# This one is tricky: since we don't have primary keys to keep only one record,
# use the physical `ctid`
safety_assureddo
execute"DELETE FROM preview_cards_statuses p WHERE p.status_id IN (#{ids.join(', ')}) AND p.ctid NOT IN (SELECT q.ctid FROM preview_cards_statuses q WHERE q.status_id = p.status_id LIMIT 1)"