Bruce Momjian <[EMAIL PROTECTED]> writes: > Tom Lane wrote: >> But then what happens when you want to update a second tuple on the same >> page? None of our existing plan types release and reacquire pin if they >> don't have to, and I really doubt that we want to give up that >> optimization.
> You will prune when you lock the page and at that point unless you got > enough room for both tuples I doubt trying just before the second tuple > is going to help. No, you're missing the point completely. If the free space on the page is, say, 1.5x the average tuple size, the code *won't* prune, and then it will be stuck when it goes to do the second tuple update, because there is no chance to reconsider the prune/no-prune decision after some space is eaten by the first update. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match