"Zeugswetter Andreas ADI SD" <Zeug...@spardat.at> writes:

Well there's another detail you have to cover aside from rolling back your xmin. You have to find the rest of the snapshot including knowing what other transactions were in-progress at the time you want to flash back to.

If you just roll back xmin and set xmax to the same value you'll get a consistent view of the database but it may not match a view that was ever current. That is, some of the transactions after the target xmin may have committed before that xmin. So there was never a time in the database when they were invisible but your new xmin was visible.

I think to do this you'll need to periodically record a snapshot and then later restore one of those saved snapshots. Not sure where would be a good place to record them. The WAL seems like a handy place but digging through the WAL would be annoying.

Incidentally this is one of the things that would be useful for read-only access to PITR warm standby machines.