> On 12 Dec 2024, at 23:08, Masahiko Sawada <sawada.mshk@gmail.com> wrote:
>
> Pushed
Hi Masahiko!
I’ve found some inconsistency in handling of overflow. I’m not sure we should handle it, but anyway.
postgres=# select x,
uuid_extract_timestamp(uuidv7((x::text || ' year'::text)::interval)),
(x::text || ' year'::text)::interval
from generate_series(237,238) x;;
x | uuid_extract_timestamp | interval
-----+-----------------------------+-----------
237 | 2262-01-30 13:43:23.737+05 | 237 years
238 | 10598-02-10 19:41:13.736+05 | 238 years
(2 rows)
The thing is per RFC we represent time as number of nanoseconds since UNIX epoch. And we use int64, which will overflow
inyear 2262. I sincerely wish us to see this great year.
We can have a couple more centuries if we resort to unsigned int 64.
But it would be great to make our code work until
postgres=# select uuid_extract_timestamp('FFFFFFFF-FFFF-7FFF-bFFF-FFFFFFFFFFFF');
uuid_extract_timestamp
-----------------------------
10889-08-02 10:31:50.655+05
(1 row)
And using uint64 won’t help us.
Can we use int128 in code? Or, perhaps, carry this extra 10 bits in the extra argument of generate_uuidv7()? Or,
perhaps,leave things as they stand now?
Thanks!
Best regards, Andrey Borodin.
