Re: Fix formatting of Interval output

Joseph Koshakow <koshy44(at)gmail(dot)com> writes:
> When formatting the output of an Interval, we call abs() on the hours
> field of the Interval. Calling abs(INT_MIN) returns back INT_MIN
> causing the output to contain two '-' characters. The attached patch
> fixes that issue by special casing INT_MIN hours.

Good catch, but it looks to me like three out of the four formats in
EncodeInterval have variants of this problem --- there are assumptions
throughout that code that we can compute "-x" or "abs(x)" without
fear. Not much point in fixing only one symptom.

Also, I notice that there's an overflow hazard upstream of here,
in interval2tm:

regression=# select interval '214748364 hours' * 11;
ERROR: interval out of range
regression=# \errverbose
ERROR: 22008: interval out of range
LOCATION: interval2tm, timestamp.c:1982

There's no good excuse for not being able to print a value that
we computed successfully.

I wonder if the most reasonable fix would be to start using int64
instead of int arithmetic for the values that are potentially large.
I doubt that we'd be taking much of a performance hit on modern
hardware.

regards, tom lane