Horton

Re: UUID v7

Andrey Borodin <amborodin86@gmail.com>

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From: Andrey Borodin <amborodin86@gmail.com>
To: Jelte Fennema <postgres@jeltef.nl>
Cc: Nick Babadzhanian <pgnickb@gmail.com>, "Andrey M. Borodin" <x4mmm@yandex-team.ru>, Mat Arye <mat@timescaledb.com>, Peter Eisentraut <peter.eisentraut@enterprisedb.com>, Tom Lane <tgl@sss.pgh.pa.us>, Daniel Gustafsson <daniel@yesql.se>, Matthias van de Meent <boekewurm+postgres@gmail.com>, Nikolay Samokhvalov <samokhvalov@gmail.com>, "Kyzer Davis (kydavis)" <kydavis@cisco.com>, Andres Freund <andres@anarazel.de>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, "brad@peabody.io" <brad@peabody.io>, "wolakk@gmail.com" <wolakk@gmail.com>, sergeyprokhorenko@yahoo.com.au
Date: 2023-10-09T18:46:06Z
Lists: pgsql-hackers 
On Mon, Oct 9, 2023 at 11:11 PM Jelte Fennema <postgres@jeltef.nl> wrote:
>
> I think using `now()` is quite prone to sequence rollover. With the
> current patch inserting more than 2^18~=0.26M rows into a table with
> `gen_uuid_v7()` as the default in a single transaction would already
> cause sequence rollover.

Well, the current patch will just use now()+1ms when 2^18 is
exhausted. Even if now() would be passed as an argument (however
current patch does not support an argument).

Best regards, Andrey Borodin.

Commits

  1. Fix timestamp overflow in UUIDv7 implementation.

  2. Add UUID version 7 generation function.

  3. Add some UUID support functions