Re: Re: GiST optimizing memmoves in gistplacetopage for fixed-size updates [PoC]

... BTW, a quick grep for other calls of PageIndexTupleDelete suggests
that SPGiST could make very good use of PageIndexTupleOverwrite, and
there may be use for it in GIN too.

I see one place in btree where there's a PageIndexTupleDelete and then
an insert, but it's unlikely to be worth touching because the page is
expected to be empty after the PageIndexTupleDelete; so there's no
data movement we could avoid in that case.

I don't plan to investigate these cases myself, but somebody should.
        regards, tom lane