Re: Infinite Interval - Mailing list pgsql-hackers

From Ashutosh Bapat
Subject Re: Infinite Interval
Date
Msg-id CAExHW5vT1_P=pzNhvyf2vPmRURenzyu0v0o0qpvxkzf8BeX=4w@mail.gmail.com
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In response to Re: Infinite Interval  (Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>)
Responses Re: Infinite Interval  (Joseph Koshakow <koshy44@gmail.com>)
List pgsql-hackers
I hurried too much on the previous patch. It introduced other
problems. Attached is a better patch and also fixes problem below
#select 'infinity'::interval * 0;
 ?column?
----------
 infinity
(1 row)

with the patch we see
#select 'infinity'::interval * 0;
2023-03-31 18:00:43.131 IST [240892] ERROR:  interval out of range
2023-03-31 18:00:43.131 IST [240892] STATEMENT:  select
'infinity'::interval * 0;
ERROR:  interval out of range

which looks more appropriate given 0 * inf = Nan for float.

There's some way to avoid separate checks for infinite-ness of
interval and factor and use a single block using some integer
arithmetic. But I think this is more readable. So I avoided doing
that. Let me know if this works for you.

Also added some test cases.

--
Best Wishes,
Ashutosh Bapat

On Fri, Mar 31, 2023 at 3:46 PM Ashutosh Bapat
<ashutosh.bapat.oss@gmail.com> wrote:
>
> On Tue, Mar 28, 2023 at 7:17 PM Ashutosh Bapat
> <ashutosh.bapat.oss@gmail.com> wrote:
>  > make sure that every
> > operator that interval as one of its operands or the result has been
> > covered in the code.
>
> time_mi_time - do we want to add an Assert to make sure that this
> function does not produce an Interval structure which looks like
> non-finite interval?
>
> multiplying an interval by infinity throws an error
> #select '5 days'::interval * 'infinity'::float8;
> 2023-03-29 19:40:15.797 IST [136240] ERROR:  interval out of range
> 2023-03-29 19:40:15.797 IST [136240] STATEMENT:  select '5
> days'::interval * 'infinity'::float8;
> ERROR:  interval out of range
>
> I think this should produce an infinite interval now. Attached patch
> to fix this, to be applied on top of your patch. With the patch
> #select '5 days'::interval * 'infinity'::float8;
>  ?column?
> ----------
>  infinity
> (1 row)
>
> Going through the tests now.
>
> --
> Best Wishes,
> Ashutosh Bapat

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