Re: Some clean-up work in get_cheapest_group_keys_order() - Mailing list pgsql-hackers

David Rowley <dgrowleyml@gmail.com> writes:
> * I think list_truncate(list_copy(list), n) is a pretty bad way to
> copy the first n elements of a list, especially when n is likely to be
> 0 most of the time. I think we should just add a function called
> list_copy_head(). We already have list_copy_tail().

Agreed, but I think there are other instances of that idiom that
should be cleaned up while you're at it.

> I think the first 3 are worth fixing in PG15 since all that code is
> new to that version. The 4th, I'm so sure about.

I'd say keeping v15 and v16 in sync here is worth something.

            regards, tom lane