Re: Option to undo last update on table.

On 2/15/07, RPK <rohitprakash123(at)indiatimes(dot)com> wrote:
>
> Is there any option in PGSQL to undo last changes done on a table? Any
> feature similar to "FlashBack Query" in Oracle.
>

The only way I could imagine that you could implement a flashback query in
PostgreSQL is if you ignored everyone's advice and didn't vacuum <not a
good idea>.

Oracle uses an undo tablespace which records all of the information to
"rollback" to an older version of row xyz, but PostgreSQL stores a "new
version of row xyz" in the same data file and vacuum flags the "old version
of row xyz" for deletion which may quickly get overwritten (or may be
unusable for other reasons???).

As for others that may be interested, the flashback feature allows you to
specify essentially the "version" to use when executing the query. And it
is typically done by specifying the SCN (which should be equivalent to the
xid for PostgreSQL) OR a timestamp.

--
Chad
http://www.postgresqlforums.com/