> On 24 Jan 2024, at 17:31, Aleksander Alekseev <aleksan...@timescale.com>
> wrote:
>
> Hi,
>
>> Cfbot also seems to be happy with the patch so I'm changing the CF
>> entry status to RfC.
>
> I've found a bug:
>
> ```
> =# select now() - interval '5000 years';
> ?column?
> ----------------------------------------
> 2977-01-24 15:29:01.779462+02:30:17 BC
>
> Time: 0.957 ms
>
> =# select uuidv7(now() - interval '5000 years');
> uuidv7
> --------------------------------------
> 720c1868-0764-7677-99cd-265b84ea08b9
>
> =# select uuid_extract_time('720c1868-0764-7677-99cd-265b84ea08b9');
> uuid_extract_time
> ----------------------------
> 5943-08-26 21:30:44.836+03
> ```
UUIDv7 range does not correspond to timestamp range. But it’s purpose is not in
storing timestamp, but in being unique identifier. So I don’t think it worth
throwing an error when overflowing value is given. BTW if you will subtract
some nanoseconds - you will not get back timestamp you put into UUID too.
UUID does not store timpestamp, it only uses it to generate an identifier. Some
value can be extracted back, but with limited precision, limited range and only
if UUID was generated precisely by the specification in standard (and standard
allows deviation! Most of implementation try to tradeoff something).
Best regards, Andrey Borodin.
