Re: Infinite Interval

Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>

From: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
To: Joseph Koshakow <koshy44@gmail.com>
Cc: Tom Lane <tgl@sss.pgh.pa.us>, "Gregory Stark (as CFM)" <stark.cfm@gmail.com>, jian he <jian.universality@gmail.com>, PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>
Date: 2023-03-31T12:46:12Z
Lists: pgsql-hackers

Attachments

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

Commits

  1. Support +/- infinity in the interval data type.

  2. Avoid integer overflow hazard in interval_time().

  3. Guard against overflow in make_interval().

  4. Fix minmax-multi on infinite date/timestamp values

  5. Optimize various aggregate deserialization functions, take 2

  6. Remove dead code in DecodeInterval()

  7. Accept "+infinity" in date and timestamp[tz] input.

  8. Fix overflow hazards in interval input and output conversions.