I think I read somewhere (sorry for not being precise) that when someone issues a query, postgresql gives a snapshot of the database at that time and that it is also possible to get a snaphshot of the database at any time if a vacuum have not been done.

Andrew Sullivan a écrit :

On Sat, May 18, 2002 at 10:45:42AM +0200, Fathi Ben Nasr wrote:
> Hello,
>
>     I have made a msitake (used where ...<> in an update wher i sould
> have used where ...=) and wanted to have the values back.
> rollback; didn't give anything as I didn't included my upadet in a
> transaction.
Then they're gone.
> I now I could have back everything (if I don't make a vacuum) from the
> database but don't how.
Restore from backups.
A
--
----
Andrew Sullivan                               87 Mowat Avenue
Liberty RMS                           Toronto, Ontario Canada
<andrew@libertyrms.info>                              M6K 3E3
                                         +1 416 646 3304 x110