On Thu, Dec 22, 2005 at 11:18:22AM +0100, Martijn van Oosterhout wrote: > On Thu, Dec 22, 2005 at 10:52:58AM +0100, REYNAUD Jean-Samuel wrote: > > Hi > > > > I've just tried it, and it works. So it's a good work-around. > > > > Though, is it a wanted feature to have a function being performed on > > each row before the offset ? > > Well, saying offset 5000 pretty much means to calculate the first 5000 > rows and throw away the result. To calculate that it needs to execute > the function each time. What happens if the function has side-effects > like in your case? What if you had a WHERE clause that depended on the > result of that function? > > If the function has no side-effects, like say pow() then the backend > could skip but that should be transparent to the user. SQL allows you > specify the way you want it and PostgreSQL is simply executing what you > wrote down...
Well, it would be a good optimization to make if the function is immutable and isn't otherwise referenced (ie: by WHERE or ORDER BY), there's no reason I can think of to execute it as you read through the rows. Might be able to do this with STABLE functions as well. TODO? -- Jim C. Nasby, Sr. Engineering Consultant [EMAIL PROTECTED] Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461 ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
