Matthew Wakeling <matthew(at)flymine(dot)org> writes:
> Very clever. Yes, that is what is happening. I'm surprised that the system
> doesn't buffer the inner side to avoid having to rescan each time, but
> then I guess you would have problems if the buffer grew larger than
> memory.
Well, it does consider adding a Materialize node for that purpose,
but in this case it evidently thought a sort was cheaper.
regards, tom lane