David, if you can update your patch with some docs to explain the behaviour, it looks complete enough to think about committing it in early January, to allow other patches that depend upon it to stand a chance of getting into 9.5. (It is not yet ready, but I see it could be).
I've been thinking of bumping this patch to the June commitfest as the patch only exists to provide the basic infrastructure for things like parallel aggregation, aggregate before join, and perhaps auto updating materialised views.
It seems unlikely that any of those things will happen for 9.5.
Does anybody object to me moving this to June's commitfest?
