INSERT INTO labelers (did, cid, reasons, subject_types, subject_collections)
VALUES ($1, $2, $3, $4, $5)
ON CONFLICT (did) DO UPDATE SET cid=EXCLUDED.cid,
                                reasons=EXCLUDED.reasons,
                                subject_types=EXCLUDED.subject_types,
                                subject_collections=EXCLUDED.subject_collections,
                                indexed_at=NOW()