I have no idea if there's a standard name or what it may be, but for
what it's worth, this sounds similar to the optimizations I wanted
for a different query:
http://archives.postgresql.org/pgsql-performance/2005-11/msg00037.php
1. Recognize that a term constant across the whole sort is
irrelevant. (In my earlier case, a constant number, but here MAX
(xxx), which seems harder.)
2. Put together two sequences already in the appropriate order,
without resorting. (In my case, a union; here a join.)
though I no longer need them for that problem. I'm quite happy with
the client-side solution we came up with.
--
Scott Lamb <http://www.slamb.org/>