| From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
|---|---|
| To: | Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> |
| Cc: | Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>, pgsql-committers(at)postgresql(dot)org |
| Subject: | Re: pgsql: Fix NUMERIC modulus to properly truncate |
| Date: | 2005-06-05 04:51:43 |
| Message-ID: | 911.1117947103@sss.pgh.pa.us |
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| Lists: | pgsql-committers pgsql-hackers |
Christopher Kings-Lynne <chriskl(at)familyhealth(dot)com(dot)au> writes:
>> No, I don't think so. It doesn't seem to be something that enough
>> people use to risk the change in behavior --- it might break something
>> that was working. But, if folks want it backported we can do it. It is
>> only a change to properly do modulus for numeric.
> Well, from my point of view it's an absolute mathematical error - i'd
> backport it. I can't see anyone relying on it :)
Doesn't this patch break the basic theorem that
a = trunc(a / b) * b + (a mod b)
? If division rounds and mod doesn't, you've got pretty serious issues.
regards, tom lane
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