I wrote:
> I'm now inclined to think that we should toss every single line of that
> code, take RelationGetBufferForTuple out of the equation, and have just
> *one* place that rechecks for PageAllVisible having just become set.
> It's a rare enough case that optimizing it is completely not worth the
> code complexity and risk (er, reality) of hard-to-locate bugs.
Alternatively, we could do what you suggested and redefine things
so that one is only allowed to set the all-visible bit while holding
superexclusive lock; which again would allow an enormous simplification
in heap_update and cohorts. Either way, it's hard to argue that
heap_update hasn't crossed the complexity threshold where it's
impossible to maintain safely. We need to simplify it.
regards, tom lane
