Re: Postgresql indices (was Re: lisp mail archive software)

On Mon, Jul 07, 2003 at 10:08:18AM -0400, Zachary Beane wrote:
> On Mon, Jul 07, 2003 at 02:53:10PM +0100, Daniel Barlow wrote:
> > -----BEGIN PGP SIGNED MESSAGE-----
> > Hash: SHA1
> > 
> > John DeSoi <[email protected]> writes:
> > 
> > > I suspected this was the case. I'm doing something similar and opted
> > > for a serial primary key for instances. It would be nice get an object
> > > ID back from the insert without the need to call currval, but I
> > > thought this was the best way to go since indexing is taken care of
> > > with the primary key specification.
> > 
> > Isn't that potentially racey?  What happens if another user does an
> > insert between when you do yours and when you call currval?
> 
> This is a Postgres FAQ, and the answer is no. 'currval' is tracked per
> session so you'll always get the result of your own most-recent
> 'nextval', not someone else's.

Also, FWIW, I typically select nextval first, then use that for the
insert. In some situations it can help prevent UI glitches like a
double-clicked "submit" button.

Zach