Re: review: More frame options in window functions

Alvaro Herrera <alvherre@commandprompt.com> writes:
> Tom Lane escribi�:
>> Yeah, I don't immediately see anything that would justify going to
>> that level of effort.  Adding +/- as support functions for btree
>> seems like the thing to do.

> Would it work to use a fake access method instead?

Then you'd have to duplicate all the information in a btree opclass;
*and* teach all the stuff that knows about btree to know about fakeam
instead.  Doesn't seem like there's any win there.

> If we add it to
> btree, will we be able to backtrack and move that to a separate catalog
> if we ever determine that it would have been better?

Backwards compatibility with existing user-type definitions is one big
reason to *not* try to pull ORDER BY information out of btree.
        regards, tom lane