PostgreSQL, already a mature database, needs to have more options for
recovery as compared to proprietary databases. I just worked with Oracle's
FlashBack query feature in Oracle 9i and FlashBack Table feature in 10g.
Future versions of PostgreSQL must have similar features which enable users
to bring Table(s) and/or Database(s) to a desired Time Stamp.
Check out my proposal for Temporal extensions. Ultimately, creating valid
time and transaction time tables would be possible through my proposal. Please
check it out.