Jeff Davis <pgsql(at)j-davis(dot)com> wrote:
> I don't think this function really cares about the visibility with
> respect to the current snapshot, right?
What it cares about is whether some other particular top level
transaction wrote a tuple which we *would* read except that it is
not visible to us because that other top level transaction is
concurrent with ours. If so, we want to flag a read-write conflict
out from our transaction and in to that other transaction.
-Kevin