On Tue, Jul 12, 2005 at 04:30:04PM +0300, Hannu Krosing wrote: > Where in the source is the decision about the placement new tuple (on > which page to put it) made ?
heap_insert and heap_update. They get a page with free space from the FSM, or extend the relation, or --in heap_update case-- try to use the same page. > I'd like to take a look at adding "gravity" to that decision, do that I > can make postgres to decide to place new tuple (inserted or updated) > near the beginning of file, in order to make it possible for ordinary > (lazy) vacuum to shrink relations more often, initially controlled by > GUC, maybe later by some other, more automatic hints, like % of empty > pages. You'll have to modify the FSM code, I guess. -- Alvaro Herrera (<alvherre[a]alvh.no-ip.org>) "Ni aun el genio muy grande llegarÃa muy lejos si tuviera que sacarlo todo de su propio interior" (Goethe) ---------------------------(end of broadcast)--------------------------- TIP 6: explain analyze is your friend
