Your problem is taht you have excluded the public schema from the search_path. All functions and types is in the public schema (by default)

So what you have to do is just include the public schema in the search_path

SET search_path TO sml, public;

means that the database will write to sml if you don't give any schema

SET search_path TO public, sml;

means that the database will write to public if no schema is given.

But in both cases both schemas will be searched for tables, functions and so on

Your problem is that you have excluded the public schema from the search_path. All functions and types is in the public schema (by default)

So what you have to do is just include the public schema in the search_path

SET search_path TO sml, public;

means that the database will write to sml if you don't give any schema

SET search_path TO public, sml;

means that the database will write to public if no schema is given.

But in both cases both schemas will be searched for tables, functions and so on