Re: UUID v7

From: "Andrey M(dot) Borodin" <x4mmm(at)yandex-team(dot)ru>
To: Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com>
Cc: Sergey Prokhorenko <sergeyprokhorenko(at)yahoo(dot)com(dot)au>, Jelte Fennema-Nio <postgres(at)jeltef(dot)nl>, Michael Paquier <michael(at)paquier(dot)xyz>, Aleksander Alekseev <aleksander(at)timescale(dot)com>, pgsql-hackers mailing list <pgsql-hackers(at)postgresql(dot)org>, Peter Eisentraut <peter(at)eisentraut(dot)org>, Przemysław Sztoch <przemyslaw(at)sztoch(dot)pl>, "David G(dot) Johnston" <david(dot)g(dot)johnston(at)gmail(dot)com>, Mat Arye <mat(at)timescaledb(dot)com>, Matthias van de Meent <boekewurm+postgres(at)gmail(dot)com>, Nikolay Samokhvalov <samokhvalov(at)gmail(dot)com>, Junwang Zhao <zhjwpku(at)gmail(dot)com>
Subject: Re: UUID v7
Date: 2024-11-01 04:53:36
Message-ID: 3D3C3CFB-A689-47F0-968E-E136D6B126CF@yandex-team.ru
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> On 1 Nov 2024, at 03:00, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
>
> Therefore, if the
> system clock moves backward due to NTP, we cannot guarantee
> monotonicity and sortability. Is that right?

Not exactly. Monotonicity is ensured for a given backend. We make sure that timestamp is advanced at least for ~250ns forward on each UUID generation. 60 bits of time are unique and ascending for a given backend.

Thanks!

Best regards, Andrey Borodin.

In response to

  • Re: UUID v7 at 2024-10-31 23:00:47 from Masahiko Sawada

Responses

  • Re: UUID v7 at 2024-11-01 06:33:08 from Masahiko Sawada

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