I wrote:
> A preliminary check-world run finds no places where the output changes,
> but I've not tried this with SELinux yet.
After trying it (against yesterday's sources) on my SELinux-capable
machine, I see no evidence that we need any output ordering changes
at all if we go this route. This is probably unsurprising considering
that the old btree code used to provide mostly-reverse-insertion-order
scan order.
regards, tom lane