Re: Unexpected interval comparison

On 03/21/2017 07:42 AM, Tom Lane wrote:
> Frazer McLean <frazer(at)frazermclean(dot)co(dot)uk> writes:
>> I came across an unexpected comparison (tested on PostgreSQL 9.4 and
>> 9.6) for intervals with a large difference in magnitude.
>
>> '1 year'::interval > '32618665 years'::interval;
>
>> Is this a bug?
>
> It looks like the problem is overflow of the result of interval_cmp_value,
> because it's trying to compute
>
> =# select '32618665'::int8 * 30 * 86400 * 1000000;
> ERROR: bigint out of range
>
> It's not immediately obvious how to avoid that while preserving the same
> comparison semantics :-(

Not sure if it helps but this works:

test=# select extract(epoch from '1 year'::interval) > extract(epoch
from '32618665 years'::interval);
?column?
----------
f

>
> regards, tom lane
>
>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com