| From: | Sergey Prokhorenko <sergeyprokhorenko(at)yahoo(dot)com(dot)au> |
|---|---|
| To: | Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> |
| Cc: | "Andrey M(dot) Borodin" <x4mmm(at)yandex-team(dot)ru>, 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>, Stepan Neretin <sncfmgg(at)gmail(dot)com> |
| Subject: | Re: UUID v7 |
| Date: | 2024-11-09 17:07:04 |
| Message-ID: | 1165679715.493882.1731172024740@mail.yahoo.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Saturday 9 November 2024 at 01:00:15 am GMT+3, Masahiko Sawada <sawada(dot)mshk(at)gmail(dot)com> wrote:
> the microsecond part is working also as a counter in a sense. IT seems fine to me but I'm slightly concerned that there is no guidance of such implementation in RFC 9562.
In fact, there is guidance of similar implementation in RFC 9562:https://datatracker.ietf.org/doc/html/rfc9562#name-monotonicity-and-counters"Counter Rollover Handling:""Alternatively, implementations MAY increment the timestamp ahead of the actual time and reinitialize the counter."
> Do you think method 3 is sufficient even with microsecond precision (i.e. storing only 10 bits microseconds in rand_a space)?
The maximum write performance in PostgreSQL is approximately 500 rows per millisecond, but under normal conditions 50 rows per millisecond. This corresponds to a precision of 2 microseconds and 20 microseconds respectively.
Andrey Borodin's implementation of method 3 provides a precision of approximately 0.25 microseconds.
You offer a precision of approximately 0.98 microseconds. This is about twice as good as what is needed for 500 rows per millisecond write performance. But in the near future, this may not be enough for the highest-performance systems.
Sergey Prokhorenkosergeyprokhorenko(at)yahoo(dot)com(dot)au
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Rishu Bagga | 2024-11-09 17:32:14 | Re: Proposal to add page headers to SLRU pages |
| Previous Message | Nathan Bossart | 2024-11-09 15:59:42 | Re: New GUC autovacuum_max_threshold ? |