Re: INOUT parameters in procedures

why just OUT variables are disallowed?

The oracle initializes these values to NULL - we can do same?

Minimally this message is not too friendly, there should be hint - "only INOUT is suported" - but better support OUT too - from TOP OUT variables should not be passed. from PL should be required.

I wrote recursive procedure. The call finished by exception. Why?

 create or replace procedure p(x int,inout a int, inout b numeric)
as $$
begin
raise notice 'xxx % %', a, b;
if (x > 1) then
  a := x / 10;
  b := x / 2;
  call p(b::int, a, b);
end if;
end;
$$ language plpgsql;
CREATE PROCEDURE
postgres=# call p(100, -1, -1);
NOTICE:  xxx -1 -1
NOTICE:  xxx 10 50
NOTICE:  xxx 5 25
NOTICE:  xxx 2 12
NOTICE:  xxx 1 6
NOTICE:  xxx 0 3
NOTICE:  xxx 0 1
ERROR:  unsupported target
CONTEXT:  PL/pgSQL function p(integer,integer,numeric) line 4 at CALL
SQL statement "CALL p(b::int, a, b)"
PL/pgSQL function p(integer,integer,numeric) line 4 at CALL
SQL statement "CALL p(b::int, a, b)"
PL/pgSQL function p(integer,integer,numeric) line 4 at CALL
SQL statement "CALL p(b::int, a, b)"
PL/pgSQL function p(integer,integer,numeric) line 4 at CALL
SQL statement "CALL p(b::int, a, b)"
PL/pgSQL function p(integer,integer,numeric) line 4 at CALL

Because these variables are INOUT then it should work.

This issue can be detected in compile time, maybe?

postgres=# create or replace procedure p(x int,inout a int, inout b numeric)
as $$
begin raise notice 'xxx % %', a, b;if (x > 1) then
  a := x / 10;
  b := x / 2; call p(b::int, a, 10); <--- can be detected in compile time?
end if;
end;
$$ language plpgsql;

Is terrible, how this patch is short.

Regards

Pavel