Tom,
> In principle, yeah, we could make it do that, but it seems like a likely
> source of maintenance headaches. This example is not exactly compelling
> enough to make me want to do it. Large OFFSETs are always going to be
> problematic from a performance standpoint, and the fact that we could
> short-circuit this one corner case isn't really going to make them much
> more usable.
It's not that uncommon of a corner case though; it's one which happens
all the time in webapps which paginate. People just have to ask for a
page after the end. It's really a question of how simple the code to
make the optimization would be; if it would be a 5-line patch, then it's
worth it; if it would be a 110-line refactor, no.
Lemme see if I can figure it out ...
--
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com