"Pavel Stehule" <pavel.stehule@hotmail.com> writes:
> if I comprehended it well CURSOR_OPT_SCROLL is set only when SCROLL is cheap
> (not when is possible). It's true?
Nope. If you want a scrollable plan you need to make sure you tell the
planner about it. SPI_cursor_open is not in charge, it's merely looking
at what the planner did.
As for that other stuff, when and if we support it, it would be time to
add a SPI entry point that supports it. I'm disinclined to add an API
on speculation though --- by the time the feature actually exists, we
might not like the API anymore anyway.
regards, tom lane