Tom Lane wrote:
> 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.
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.
-- Bruce Momjian <bruce@momjian.us> http://momjian.us EnterpriseDB
http://www.enterprisedb.com
+ If your life is a hard drive, Christ can be your backup. +
