Bruce Momjian <bruce@momjian.us> writes:
> Tom Lane wrote:
>> The problem is you can't prune anymore once you have existing pin on the
>> target page. I'd really like to get around that, but so far it seems
>> unacceptably fragile --- the executor really doesn't expect tuples to
>> get moved around underneath it.
> I thought you could do the pruning before you pin the page only in
> update/insert cases.
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.
regards, tom lane