Actually, in your case it's probably the new optimisation regarding the use
of IN (subquery). They're now optimised to the same lavel as EXISTS IIRC.
On Wed, Nov 12, 2003 at 05:46:23PM -0800, Reece Hart wrote:
> On Wed, 2003-11-12 at 09:04, jake johnson wrote:
>
> > I also posted about the performance increase of 7.4, but I think that
> > much of the difference you're seeing (because it's such a large
> > difference) is probably due to the cleanliness of a newly restored
> > database from backup.
>
>
> I agree that this seems likely, except that the 7.3.4 database is
> vacuumed nightly, and analyzed periodically. And about a week ago I
> reclustered on the index intended to most facilitate this select.
> Furthermore, merely hardcoding the subselect result achieves a
> tremendous improvement (which was the workaround I used). So, I'm pretty
> sure that it's not a vacuum, index use, or cleanliness issue.
>
> I also meant to add in my original post that the system is a dual 2.4G
> xeon with 4GB of RAM.
>
> -Reece
>
>
>
> --
> Reece Hart, http://www.in-machina.com/~reece/, GPG:0x25EC91A0 0xD178AAF9
--
Martijn van Oosterhout <kleptog@svana.org> http://svana.org/kleptog/
> "All that is needed for the forces of evil to triumph is for enough good
> men to do nothing." - Edmond Burke
> "The penalty good people pay for not being interested in politics is to be
> governed by people worse than themselves." - Plato