what data type should be returned by sum(float4)

Hello,

http://www.postgresql.org/docs/devel/static/functions-aggregate.html

The documentation says that return type of sum(expression) is... bigint for smallint or int arguments, numeric for
bigintarguments, double precision for floating-point arguments, otherwise the same as the argument data type 

Does it expect sum(float4) returns float8, doesn't it?

On the other hand, catalog definition seems to me it returns float4.

postgres=# select * from pg_aggregate where aggfnoid in (2110, 2111);   aggfnoid    | aggkind | aggnumdirectargs |
aggtransfn| aggfinalfn | aggmtra 
nsfn | aggminvtransfn | aggmfinalfn | aggfinalextra | aggmfinalextra | aggsortop| aggtranstype | aggtransspace |
aggmtranstype| aggmtransspace | agginitval | 
aggminitval
----------------+---------+------------------+------------+------------+--------
-----+----------------+-------------+---------------+----------------+----------
-+--------------+---------------+---------------+----------------+------------+-
------------pg_catalog.sum | n       |                0 | float4pl   | -          | -    | -              | -
|f             | f              |         0|          700 |             0 |             0 |              0 |
|pg_catalog.sum| n       |                0 | float8pl   | -          | -    | -              | -           | f
   | f              |         0|          701 |             0 |             0 |              0 |            | 
(2 rows)

Which one shall be fixed?

Thanks,
--
NEC OSS Promotion Center / PG-Strom Project
KaiGai Kohei <kaigai@ak.jp.nec.com>