Re: Fix overflow in justify_interval related functions

On Mon, Feb 14, 2022 at 01:55:56PM -0500, Tom Lane wrote:
> Nathan Bossart <nathandbossart@gmail.com> writes:
>> On Sun, Feb 13, 2022 at 01:28:38PM -0500, Joseph Koshakow wrote:
>>> +SELECT justify_hours(interval '2147483647 days 24 hrs');
>>> +ERROR:  interval out of range
> 
>> The docs [0] claim that the maximum value for interval is 178 million
>> years, but this test case is only ~6 million.  Should we instead rework the
>> logic to avoid overflow for this case?
> 
> I think the docs are misleading you on this point.  The maximum
> value of the months part of an interval is 2^31 months or
> about 178Myr, but what we're dealing with here is days, which
> likewise caps at 2^31 days.  justify_hours is not chartered
> to transpose up to months, so it can't avoid that limit.

Makes sense.  So we could likely avoid it for justify_interval, but the
others are at the mercy of the interval implementation.

-- 
Nathan Bossart
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