BUG #4657: mod() makes a mistake in calculation in v8.3

Started by Fujii Masaoabout 17 years ago2 messagesbugs
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#1Fujii Masao
masao.fujii@gmail.com

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,

#2Tom Lane
tgl@sss.pgh.pa.us
In reply to: Fujii Masao (#1)
Re: BUG #4657: mod() makes a mistake in calculation in v8.3

"Fujii Masao" <masao.fujii@gmail.com> writes:

Why don't we backport this?
http://archives.postgresql.org/pgsql-committers/2008-04/msg00030.php

See the thread in which it was decided not to apply that to 8.3.

regards, tom lane