The following bug has been logged online:
Bug reference: 4657
Logged by: Fujii Masao
Email address: masao.fujii@gmail.com
PostgreSQL version: 8.3.6 on x86_64
Operating system: Red Hat Enterprise Linux Server release 5.1 (Tikanga)
Description: mod() makes a mistake in calculation in v8.3
Details:
In 8.3, I found the bug of 'mod' function to make an error in calculation
when the second argument is defined as 'numeric'.
postgres=# SELECT version();
version
----------------------------------------------------------------------------
-------------------------------
PostgreSQL 8.3.6 on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC)
4.1.2 20070626 (Red Hat 4.1.2-14)
(1 row)
postgres=# SELECT mod(70000, 35);
mod
-----
0
(1 row)
postgres=# SELECT mod(70000.0, 35.0);
mod
------
35.0
(1 row)
On the other hand, in HEAD, mod() seems to work fine.
postgres=# SELECT version();
version
----------------------------------------------------------------------------
------------------------------------------
PostgreSQL 8.4devel on x86_64-unknown-linux-gnu, compiled by GCC gcc (GCC)
4.1.2 20070626 (Red Hat 4.1.2-14), 64-bit
(1 row)
postgres=# SELECT mod(70000, 35);
mod
-----
0
(1 row)
postgres=# SELECT mod(70000.0, 35.0);
mod
-----
0.0
(1 row)
I guess the following change fixed the bug which I found. Right?
Why don't we backport this?
http://archives.postgresql.org/pgsql-committers/2008-04/msg00030.php
Regards,
