> item_max_date() looks like this:
> select max(dtstamp) from items where channel = $1 and link = $2;
It is too bad the (channel, link) index doesn't have dtstamp at the end
of it, otherwise the below query would be a gain (might be a small one
anyway).
select dtstamp
from items
where channel = $1
and link = $2
ORDER BY dtstamp DESC
LIMIT 1;
Could you show us the exact specification of the function? In
particular, did you mark it VOLATILE, IMMUTABLE, or STABLE?
I hope it isn't the first or second one ;)