Richard Huxton <dev(at)archonet(dot)com> writes:
> From a curiosity point of view, there apparently used to be a
> "time-travel" feature in (really) old versions of PG.
There still is a contrib module that supports this using triggers
(look in contrib/spi/). It's looking a bit dated --- for instance
it uses abstime columns, which ought to get updated to timestamptz.
But it'd be a starting point.
regards, tom lane