On Sun, Mar 06, 2005 at 11:54:52PM +0200, Ioannis Theoharis wrote:
> > Visibility information. An index contains references to all rows in all
> > transactions. You need to go back to the table to work out if the row
> > is visible in your transaction.
> >
> > Hope this helpsm
>
> Yes at all.
> You have a lot of work for future postgresql' versions :-))
It's a fairly corner case feature, only for the case where you're
looking for the existance of an index key but don't want any other
data. I don't personally have any queries that could use such a
construct, though maybe I'm missing the point.
If someone wants to step up and write the code, well... Bit hard, it
means that everytime a row is updated the index needs to be updated
too, gotta get all the corner cases, locking, etc.
It's not high on anybodies list AFAIK...
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/
> Patent. n. Genius is 5% inspiration and 95% perspiration. A patent is a
> tool for doing 5% of the work and then sitting around waiting for someone
> else to do the other 95% so you can sue them.