Came across this problem when trying to assign to a variable a field from a
record that could come from multiple cursors. PG throws an error - "
ERROR: type of parameter 7 (bigint) does not match that when preparing the
plan (unknown)". If I make the null column in c1 null::bigint to match cursor
c2, it works fine.
Where is this plan coming from? Why would it match c1 to a plan coming from c2?
In reality, the two cursors in question are wildly different- a join of about
10 completely different tables. When I saw the text of the error I was a bit
concerned that it was being overly flexible in matching the current cursor to
another.
It errors out on the assignment to I, not the fetch. (maybe the fetch isn't
actually being done until the data in r is used).
CREATE OR REPLACE FUNCTION demo.test_cursor_bug ( a IN integer ) RETURNS void AS
$BODY$
DECLARE
c1 cursor FOR SELECT 1 as shipmentid, null as olmid;
c2 cursor FOR SELECT 2 as shipmentid, 32::bigint as olmid;
r record;
i bigint;
BEGIN
IF ( a = 0 ) THEN
open c1;
fetch c1 INTO r;
close c1;
END IF;
IF ( a = 1 ) THEN
open c2;
fetch c2 INTO r;
close c2;
END IF;
i := r.olmid;
END;
$BODY$
LANGUAGE plpgsql;
select demo.test_cursor_bug(0);
select demo.test_cursor_bug(1);
