text: CREATE PROCEDURE test_proc1()
  LANGUAGE plperl
  AS $$
  undef;
  $$;
  
  CALL test_proc1();
  
  
  CREATE PROCEDURE test_proc2()
  LANGUAGE plperl
  AS $$
  return 5
  $$;
  
  CALL test_proc2();
  
  
  CREATE TABLE test1 (a int);
  
  CREATE PROCEDURE test_proc3(x int)
  LANGUAGE plperl
  AS $$
  spi_exec_query("INSERT INTO test1 VALUES ($_[0])");
  $$;
  
  CALL test_proc3(55);
  
  SELECT * FROM test1;
  
  
  -- output arguments
  
  CREATE PROCEDURE test_proc5(INOUT a text)
  LANGUAGE plperl
  AS $$
  my ($a) = @_;
  return { a => "$a+$a" };
  $$;
  
  CALL test_proc5('abc');
  
  
  CREATE PROCEDURE test_proc6(a int, INOUT b int, INOUT c int)
  LANGUAGE plperl
  AS $$
  my ($a, $b, $c) = @_;
  return { b => $b * $a, c => $c * $a };
  $$;
  
  CALL test_proc6(2, 3, 4);
  
  
  -- OUT parameters
  
  CREATE PROCEDURE test_proc9(IN a int, OUT b int)
  LANGUAGE plperl
  AS $$
  my ($a, $b) = @_;
  elog(NOTICE, "a: $a, b: $b");
  return { b => $a * 2 };
  $$;
  
  DO $$
  DECLARE _a int; _b int;
  BEGIN
    _a := 10; _b := 30;
    CALL test_proc9(_a, _b);
    RAISE NOTICE '_a: %, _b: %', _a, _b;
  END
  $$;
  
  
  DROP PROCEDURE test_proc1;
  DROP PROCEDURE test_proc2;
  DROP PROCEDURE test_proc3;
  
  DROP TABLE test1;
  