Fetch refcursor in pl/proxy

Question

I am using Postgresql and have the simple function that will return a refcursor to the client:

CREATE OR REPLACE FUNCTION select_user(cur refcursor, m_id text)
RETURNS setof refcursor AS $$ 
BEGIN
    OPEN $1 FOR SELECT * FROM public.users WHERE id=m_id;
    RETURN NEXT $1;
END;
$$ LANGUAGE plpgsql; 

I could fetch the data like this:

SELECT select_user('cur','999999'); FETCH ALL in cur;

Return 1 Row like this:

username   email                id
999999     999999@somewhere.cm  999999 

But the problem now, I'm using pl/proxy with Postgresql In pl/proxy server I wrote this function:

CREATE OR REPLACE FUNCTION select_user(cur refcursor, m_type integer, m_hid text)
RETURNS setof refcursor AS $$ 
   CLUSTER 'sqlcluster';
   RUN ON select_db(m_hid);
$$ LANGUAGE plproxy;

From the above function it return refcursor, but I couldn't fetch the refcursor Using this command:

SELECT select_user('cur','999999'); FETCH ALL in cur;

Return error:

SQL error:

ERROR:  cursor "cur" does not exist

Could anyone explain what's the problem?

Answer 1

The PL/Proxy function is running in a different database, and the refcursor is not valid there. You are going to have to redesign that part of the code.