For PostgreSQL with WAL logs, or in a service like RDS, can you not do a point in time recovery? Seems like an easy way to go back in time, recover the data you want, dig out any FK referents that might also have been cascade deleted etc. If you also maintained an audit log you should be able to isolate the point where the given data was deleted (if its id is in the audit log), and restore from just before it, to capture the deleted data, query it and reinsert in master.