On Thu, Mar 02, 2006 at 10:05:28AM -0500, Tom Lane wrote: > Hannu Krosing <[EMAIL PROTECTED]> writes: > > ??hel kenal p??eval, N, 2006-03-02 kell 09:53, kirjutas Zeugswetter > > Andreas DCP SD: > >> Ok, we cannot reuse a dead tuple. Maybe we can reuse the space of a dead > >> tuple by reducing the tuple to it's header info. > > Andreas' idea is possibly doable but I am not sure that I see the point. > It does not reduce the need for vacuum nor the I/O load imposed by > vacuum. What it does do is bias the system in the direction of > allocating an unreasonably large number of tuple line pointers on a page > (ie, more than are useful when the page is fully packed with normal > tuples). Since we never reclaim such pointers, over time all the pages > in a table would tend to develop line-pointer-bloat. I don't know what > the net overhead would be, but it'd definitely impose some aggregate > inefficiency.
What would be involved in reclaiming item pointer space? Is there any reason it's not done today? (I know I've been bit once by this...) -- 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 2: Don't 'kill -9' the postmaster
