Horton

Re: UUID v7

x4mmm@yandex-team.ru

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From: "Andrey M. Borodin" <x4mmm@yandex-team.ru>
To: Mat Arye <mat@timescaledb.com>
Cc: 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>, Andrey Borodin <amborodin86@gmail.com>, PostgreSQL Hackers <pgsql-hackers@postgresql.org>, "brad@peabody.io" <brad@peabody.io>, "wolakk@gmail.com" <wolakk@gmail.com>, sergeyprokhorenko@yahoo.com.au
Date: 2023-08-31T18:51:35Z
Lists: pgsql-hackers 
Thanks for interesting ideas, Mat!

> On 31 Aug 2023, at 20:32, Mat Arye <mat@timescaledb.com> wrote:
> 
> From a user perspective, it would be great to add 2 things:
> - A function to extract the timestamp from a V7 UUID (very useful for defining constraints if partitioning by the uuid-embedded timestamps, for instance).

Well, as far as I know, RFC discourages extracting timestamps from UUIDs. But we still can have such functions...maybe as an extension?

> - Can we add an optional timestamptz argument to gen_uuid_v7 so that you can explicitly specify a time instead of always generating for the current time? If the argument is NULL, then use current time. This could be useful for backfilling and other applications.

I think this makes sense. We could also have a counter as an argument. I'll try to implement that.
However, so far I haven't figured out how to implement optional arguments for catalog functions. I'd appreciate any pointers here.


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