static_expiry timestamptz,
	dynamic_expiry timestamptz,

		cart.system_time_start + '30 minutes',
		(
			select
				greatest(
					max(system_time_start),
					max(case--just to handle deleted line items. worth?
						when system_time_end = 'infinity' then '-infinity'
						else system_time_end
					end)
				)
			from line_item__between(cart.system_time_start, now())
		) + '5 minutes',

create or replace function invalidate_stale_carts() returns void as $$
	delete from cart where cart_id in (
		select cart_id
		from cart inner join line_item__between(system_time_start, now()) as l using (cart_id)
		where status = 'active'
		group by cart_id
		having now() >= least(
			cart.system_time_start + '30 minutes',
			greatest(
				max(l.system_time_start),
				max(case
					when l.system_time_end = 'infinity' then '-infinity'
					else l.system_time_end
				end)
			) + '5 minutes'
		)
	)
$$ language sql volatile;

setInterval(() => pool.query('select invalidate_stale_carts()'), 1000);