I've marked this as rejected in the commitfest, because others are
working on a more general solution with parallel workers. That's still
work-in-progress, and it's not certain if it's going to make it into
9.6, but if it does it will largely render this obsolete. We can revisit
this patch later in the release cycle, if the parallel scan patch hasn't
solved the same use case by then.
- Heikki
