Thread: Rounding incompatibility

Hi,

I have found the following strangeness on Windows versions:

create table round_test (id int primary key, value double precision);
insert into round_test(id, value) values(1, 1.5);
insert into round_test(id, value) values(2, -1.5);
insert into round_test(id, value) values(3, 3.5);
select round(value) from round_test;

psql 8.2.13 returns

2
-2
4

But psql 8.3.3 returns

1
-1
3

Trying more values it seems that 8.2 rounding works according to banker's rounding rules.
Can you confirm this?
How can I avoid this incompatibility or perhaps bug?

Thanks,
Otto

=?ISO-8859-1?Q?Havasv=F6lgyi_Ott=F3?= <havasvolgyi.otto@gmail.com> writes:
> I have found the following strangeness on Windows versions:

Were your two versions built different ways (perhaps with different
compilers)?  This comes down to what the system-supplied rint() function
does.

            regards, tom lane

On Mon, Jun 15, 2009 at 3:33 PM, Tom Lane<tgl@sss.pgh.pa.us> wrote:
> =?ISO-8859-1?Q?Havasv=F6lgyi_Ott=F3?= <havasvolgyi.otto@gmail.com> writes:
>> I have found the following strangeness on Windows versions:
>
> Were your two versions built different ways (perhaps with different
> compilers)?  This comes down to what the system-supplied rint() function
> does.

If they are our packages, then 8.2 was built with mingw/msys, and 8.3 with VC++.


--
Dave Page
EnterpriseDB UK:   http://www.enterprisedb.com

Yes, they are both your packages from your official site. So this means that in 8.2 and in earlier versions the rounding is not the regular one.

Best regards,
Otto