Horton

Re: Sequence Access Methods, round two

Matthias van de Meent <boekewurm+postgres@gmail.com>

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From: Matthias van de Meent <boekewurm+postgres@gmail.com>
To: Peter Eisentraut <peter@eisentraut.org>
Cc: Michael Paquier <michael@paquier.xyz>, Postgres hackers <pgsql-hackers@lists.postgresql.org>
Date: 2024-01-18T15:54:06Z
Lists: pgsql-hackers

Commits

Same data as JSON: GET /api/v1/messages/:b64id/commits the thread's linked commits as JSON, with link sources. API reference →

  1. Refactor init_params() in sequence.c to not use FormData_pg_sequence_data

  2. Fix comment thinko in sequence.c

  3. Group more closely cache updates for backends in sequence.c

  4. Introduce sequence_*() access functions

On Thu, 18 Jan 2024, 16:06 Peter Eisentraut, <peter@eisentraut.org> wrote:
>
> On 01.12.23 06:00, Michael Paquier wrote:
> > Please find attached a patch set that aims at implementing sequence
> > access methods, with callbacks following a model close to table and
> > index AMs, with a few cases in mind:
> > - Global sequences (including range-allocation, local caching).
> > - Local custom computations (a-la-snowflake).
>
> That's a lot of code, but the use cases are summarized in two lines?!?
>
> I would like to see a lot more elaboration what these uses cases are (I
> recognize the words, but do we have the same interpretation of them?)
> and how they would be addressed by what you are proposing, and better
> yet an actual implementation of something useful, rather than just a
> dummy test module.

At $prevjob we had a use case for PRNG to generate small,
non-sequential "random" numbers without the birthday problem occurring
in sqrt(option space) because that'd increase the printed length of
the numbers beyond a set limit. The sequence API proposed here
would've been a great alternative to the solution we found, as it
would allow a sequence to be backed by an Linear Congruential
Generator directly, rather than the implementation of our own
transactional random_sequence table.

Kind regards,

Matthias van de Meent
Neon (https://neon.tech)