cursor empty

[Philipp Kraus <philipp.kraus@xxxxxxxxxxxxxxx>]

Hello,

I have got a function with this definition:

CREATE OR REPLACE FUNCTION vectorize(refcursor)
    RETURNS SETOF refcursor 
    LANGUAGE 'plpgsql'
    COST 100
    STABLE 
    ROWS 1000
AS $BODY$

begin
	perform pivottable( 
		'_vector', 
		'select * from viewdata', 
		array['ideate', 'name', 'description', 'latitude', 'longitude'], 
		array['parametername'],
		array['parametervalue::text', 'parametervaluetext']
	);	
	open $1 scroll for select * from _vector;
	return next $1;
end

$BODY$;

The perform call creates a dynamic column pivot table, if I run manually

select pivottable( 
	'_vector', 
	'select * from viewdata', 
	array['ideate', 'name', 'description', 'latitude', 'longitude'], 
	array['parametername'],
	array['parametervalue::text', 'parametervaluetext']
);	
select * from _vector;

I get all the data in the output, so everything is fine.

My goal is now to encapsulate the two lines into a function, so I define
a stable function and based on the dynamic column set a cursor. I get in
pgadmin the column names back, but the rows are empty if I run:

select * from vectorize('myvec');
fetch all from myvec;

Can you explain me, which part is wrong? 
Thanks

Phil