Re: unlimited undo/journaling

On Wed, Jun 26, 2002 at 07:34:14PM +0200, Arnaud Le Taillanter wrote:
> On Wed, 2002-06-26 at 07:43, Carl Meyer wrote:
>
> > hello,
> >
> > i wondered how an unlimited undo feature would be realized in
> > postgresql.
> >
>
> I think Temporal SQL, which is perhaps a standard now, offers this
> functionnality. Basically, it would allow you to create a table with
> "transaction time" support and every modification would be stored
> automatically with your data.

It was actually made an SQL standard? Wow. Postgresql used to have this
feature a long time ago but it was ripped out because the overhead was
considered too high for a feature no-one used anyway.

Nowadays with view, triggers and rules you can acheive exactly the same
effect except for the nifty syntax.

> To get an idea of how simple it would be then to retrieve your data as
> stored at a particular date, see the introduction to the (draft?) TSQL
> standard :
> ftp://ftp.cs.arizona.edu/tsql/tsql2/sql3/ansi-94-276.pdf
>
> I think that the PostgreSQL developpers are very busy, so I wouldn't
> expect this feature soon :-) Anyway, you have a dream now :-)

You can see how it used to be at:

http://www.us.postgresql.org/users-lounge/docs/6.5/tutorial/x1403.htm

For now you can look in the contrib directory for time travel.
--
Martijn van Oosterhout   <kleptog@svana.org>   http://svana.org/kleptog/
> There are 10 kinds of people in the world, those that can do binary
> arithmetic and those that can't.