Re: Bug with function returning composite types.

On Mon, Mar 09, 2009 at 10:03:34AM -0500, Kevin Grittner wrote:
> >>> Kyle Butt <kylebutt(at)gmail(dot)com> wrote:
>
> > select (bug_function()).*;
>
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > psql:sql/bug_example.sql:32: NOTICE: in bug_function
> > a | b | c | d | e | f | g | h | i | j
> > ---+---+---+---+---+---+---+---+---+---
> > 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
> > (1 row)
>
> For completeness:
>
> cir=# select * from bug_function();
> NOTICE: in bug_function
> a | b | c | d | e | f | g | h | i | j
> ---+---+---+---+---+---+---+---+---+---
> 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
> (1 row)
>
> -Kevin

I noticed that it has to do with the volatility. If I declare the function as
stable (which it is) then it's executed multiple times. If I declare it as
volatile, it's only executed once.
I'm more interested in something like the following (output placed inline):

create function bug_function_2 (j_p integer) returns composite_types_test
volatile
language plpgsql
as $$
declare r composite_types_test;
begin
select * into r from composite_types_test where j = j_p;
raise notice 'in bug_function_2';
return r;
end;
$$;

select (bf2).* from (
select bug_function_2(j) as bf2 from composite_types_test
) as foo;

psql:sql/bug_example.sql:54: NOTICE: in bug_function_2
a | b | c | d | e | f | g | h | i | j
---+---+---+---+---+---+---+---+---+---
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
(1 row)

create or replace function bug_function_2 (j_p integer) returns composite_types_test
stable
language plpgsql
as $$
declare r composite_types_test;
begin
select * into r from composite_types_test where j = j_p;
raise notice 'in bug_function_2';
return r;
end;
$$;

select (bf2).* from (
select bug_function_2(j) as bf2 from composite_types_test
) as foo;

psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
psql:sql/bug_example.sql:70: NOTICE: in bug_function_2
a | b | c | d | e | f | g | h | i | j
---+---+---+---+---+---+---+---+---+---
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9
(1 row)