On Sun, Sep 25, 2005 at 12:09:24AM -0400, Tom Lane wrote: > "Jim C. Nasby" <jnasby@xxxxxxxxxxxxx> writes: > > On Sat, Sep 24, 2005 at 07:19:10PM -0400, Tom Lane wrote: > >> Currently, when a tuple is reclaimed by VACUUM, we just mark its item > >> pointer as unused (and hence recyclable). I think it might be safe to > >> decrease pd_lower if there are unused pointers at the end of the page's > >> pointer array, but we don't currently do that. > > > Sounds like a good newbie TODO? > > Uh, no, because the $64 question is whether it actually *is* safe, or > perhaps would be safe with more locking than we do now. I'm not sure of > the answer myself, and would have zero confidence in a newbie's answer. > > Decreasing pd_lower would definitely be a win if we can do it free or > cheaply. If it requires significant additional locking overhead, then > maybe not. Ok, sounds like a non-newbie TODO then. :) -- Jim C. Nasby, Sr. Engineering Consultant jnasby@xxxxxxxxxxxxx Pervasive Software http://pervasive.com work: 512-231-6117 vcard: http://jim.nasby.net/pervasive.vcf cell: 512-569-9461 ---------------------------(end of broadcast)--------------------------- TIP 3: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faq
