plpgsql memory leaks

[Pavel Stehule]

Hi

I have reported very memory expensive pattern:

CREATE OR REPLACE FUNCTION public.fx(iter integer)
 RETURNS void
 LANGUAGE plpgsql
AS $function$
declare
  c cursor(m bigint) for select distinct i from generate_series(1, m) g(i);
  t bigint;
  s bigint;
begin
  for i in 1..iter
  loop
    open c(m := i * 10000);
    s := 0;
    loop
      fetch c into t;
      exit when not found;
      s := s + t;
    end loop;
    close c; raise notice '%=%', i, s;
  end loop;
end;
$function$
;

This script takes for 100 iterations 100MB

but rewritten

CREATE OR REPLACE FUNCTION public.fx(iter integer)
 RETURNS void
 LANGUAGE plpgsql
AS $function$
declare
  t bigint;
  s bigint;
begin
  for i in 1..iter
  loop
    s := 0;
    for t in select  ic from generate_series(1, i * 10000) g(ic)
    loop
      s := s + t;
    end loop;
    raise notice '%=%', i, s;
  end loop;
end;
$function$

takes lot of megabytes of memory too.

Regards

Pavel