Hi, when using LIMIT, how do I tell the planner to only call a function for rows it returns? An example: I want to fetch the top five categories. A function get_category_text_path(cat_id int) returns the textual representation of the category. For that I do something like: SELECT id, get_category_text_path(id) FROM category ORDER BY rank LIMIT 5 Unfortunately this takes very long because it calls get_category_text_path() for all of the 450'000 categories in the table. But I only need the full text path of the top five rows. It does not matter if I declare the function to be IMMUTABLE, STABLE or VOLATILE - it gets called for every row in category (which normally is what you want I guess). How can I rewrite the query to call get_category_text_path() only for the top five rows? Thanks for hints. Markus
