BEGIN;
SET TRANSACTION ISOLATION LEVEL SERIALIZABLE;
CREATE TABLE cursor (a int);
INSERT INTO cursor VALUES (1);
DECLARE c1 NO SCROLL CURSOR FOR SELECT * FROM cursor FOR UPDATE;
UPDATE cursor SET a = 2;
FETCH ALL FROM c1;
 a 
---
(0 rows)

COMMIT;
DROP TABLE cursor;
create table to_be_evicted(x bigint);
begin;
insert into to_be_evicted values (1);
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
insert into to_be_evicted select x*10 from to_be_evicted;
select sum(x) from to_be_evicted;
     sum     
-------------
 25937424601
(1 row)

end;
drop table to_be_evicted;