Re: Float value 'Infinity' is cast to numeric 1 on Windows

Kohei KaiGai <kaigai@heterodb.com>

From: Kohei KaiGai <kaigai@heterodb.com>
To: Taiki Kondo <tai-kondo@yk.jp.nec.com>
Cc: "pgsql-bugs@postgresql.org" <pgsql-bugs@postgresql.org>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>, Hiroshi Yanagisawa <hir-yanagisawa@ut.jp.nec.com>
Date: 2017-09-27T11:06:55Z
Lists: pgsql-bugs, pgsql-hackers
Hello,

Does it make sense to put a check of "isinf(val)" and ereport prior to
the snprintf()?
It is a lightweight check more than set_var_from_str().

Thanks,

2017-09-27 19:41 GMT+09:00 Taiki Kondo <tai-kondo@yk.jp.nec.com>:
> Hi all,
>
> I build PostgreSQL 9.6.5 by Visual Studio 2013 on Windows, I found weird behavior on it.
>
> I execute following SQL, occurring ERROR is expected, but I got mysterious value 1.
>
>
> postgres=# select (float8 'inf')::numeric;
>  numeric
> ---------
>        1
> (1 row)
>
>
> On Windows, at least Visual Studio, the string of float/double value meaning
> infinity is "1.#INF" not "inf". So, set_var_from_str() called from float8_numeric()
> in utils/adt/numeric.c will return numeric value 1, and no one checks this situation.
>
> This situation is also occurring by cast from float4.
>
> I wrote a patch to add check this situation.
> Please find attached.
>
>
> Sincerely,
>
> --
> Taiki Kondo
> NEC Solution Innovators, Ltd.
>
>
>
>
> --
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-- 
HeteroDB, Inc / The PG-Strom Project
KaiGai Kohei <kaigai@heterodb.com>


Commits

  1. Fix behavior when converting a float infinity to numeric.