timeflake
sequential-uuids
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timeflake | sequential-uuids | |
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5 | 7 | |
807 | 293 | |
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6.4 | 3.6 | |
8 months ago | 7 months ago | |
Python | C | |
MIT License | MIT License |
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timeflake
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PostgreSQL UUID vs. Serial vs. Identity
Yeah, just use a UUID unless the bits to store the UUID really are your driving limitation (they're not), having a UUID that is non-linear is almost always the most straight-forward option for identifying things, for the tradeoff of human readability (though you can get some of that back with prefixes and some other schemes). I'm not going to rehash the benefits that people have brought up for UUIDs, but they're in this thread. At this point what I'm concerned about is just... what is the best kind of UUID to use -- I've recently started using mostly v1 because time relationship is important to me (despite the unfortunate order issues) and v6[0] isn't quite so spread yet. Here's a list of other approaches out there worth looking at
- isntauuid[1] (mentioned in this thread, I've given it a name here)
- timeflake[2]
- HiLo[3][4]
- ulid[5]
- ksuid[6] (made popular by segment.io)
- v1-v6 UUIDs (the ones we all know and some love)
- sequential interval based UUIDs in Postgres[7]
Just add a UUID -- this almost surely isn't going to be what bricks your architecture unless you have some crazy high write use case like time series or IoT or something maybe.
[0]: http://gh.peabody.io/uuidv6/
[1]: https://instagram-engineering.com/sharding-ids-at-instagram-...
[2]: https://github.com/anthonynsimon/timeflake
[3]: https://en.wikipedia.org/wiki/Hi/Lo_algorithm
[4]: https://www.npgsql.org/efcore/modeling/generated-properties....
[5]: https://github.com/edoceo/pg-ulid
[6]: https://github.com/segmentio/ksuid
[7]: https://www.2ndquadrant.com/en/blog/sequential-uuid-generato...
- Show HN: 128-bit, roughly-ordered, URL-safe UUIDs
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Timeflake: 128-bit, roughly-ordered, URL-safe UUIDs
- How long the user took to write the post. This can happen if the app creates the ID when the user starts editing the post and also shares a timestamp of the publication or save time.
- Whether or not the user edited the post after posting it. This can happen if the posts's displayed time doesn't match the timestamp in the ID.
- Whether or not the user prepared the post in advance and set it to post automatically. If the timestamp is very close to a round numbered time like 21:00:00, it was likely posted automatically. If the posting platform does not provide such functionality, then the user must be using some third-party software or custom software to do it. This information can help de-anonymize the user.
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[0] https://github.com/anthonynsimon/timeflake/issues/3
[1] https://firebase.google.com/docs/cloud-messaging/android/cli...
[2] https://www.eff.org/deeplinks/2017/03/five-creepy-things-you...
[3] https://digitalcontentnext.org/wp-content/uploads/2018/08/DC...
[4] https://www.eff.org/deeplinks/2016/08/windows-10-microsoft-b...
[5] https://www.eff.org/deeplinks/2020/11/macos-leaks-applicatio...
sequential-uuids
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Choosing a Postgres Primary Key
Disclaimer: not a dba so my terms might not be appropriate
I’ve seen uuid4 which replaces the first 4 bytes with a timestamp. It was mentioned to me that this strategy allows postgres to write at the end of the index instead of arbitrarily on disk. I also presume it means it has some decent sorting.
[inspiration](https://github.com/tvondra/sequential-uuids/blob/master/sequ...)
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Install extensions from PGDG repo to YugabyteDB - example with sequential_uuids
yum install -y git git clone https://github.com/tvondra/sequential-uuids.git ysqlsh -h $(hostname) --echo-all --quiet \ --file sequential-uuids/test/sql/uuids.sql | sdiff sequential-uuids/test/expected/uuids.out -
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Using a custom GUID (not provided by Postgres). What to keep in mind for performance gains
If you want to keep locality when using uuids, use a different generation function such as: https://github.com/tvondra/sequential-uuids
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Any significant performance disadvantage to using uuid as primary key?
OP, have a pretty large B2B SAAS app with all UUID pkeys, and the largest issues i'd say with UUID compared to bigint are: size, index bloat, WAL bloat, much slower GIST indexes (for exclusion constraints). You can work around some of the issues (WAL bloat, index bloat) by using a better behaved UUID generation function: https://github.com/tvondra/sequential-uuids You can get something similar for your app side of things if you need to generate UUIDs there.
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Timeflake: 128-bit, roughly-ordered, URL-safe UUIDs
Use this: https://github.com/tvondra/sequential-uuids
If you cannot install extensions, I just wrote a PL/PGSQL implementation for the time-based generator I could share.
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UUID vs int for primary key - Which is better (with auto increment), especially if you are scared you'll run out of ids?
Just fyi, UUID in Postgres is not 40 text chars, it's 16 bytes binary and has a canonical text representation. Also, you don't need to use UUIDv4, I am quite partial to: https://github.com/tvondra/sequential-uuids
What are some alternatives?
uulid.go - ULID-UUID compatibility library for generating and parsing ULIDs.
Pomelo.EntityFrameworkCore.MySql - Entity Framework Core provider for MySQL and MariaDB built on top of MySqlConnector
Dapper - Dapper - a simple object mapper for .Net
pg_tuid - generate_tuid function for postgres
pg-ulid - ULID Functions for PostgreSQL
id128 - 128-bit id generation in multiple formats
ksuid - K-Sortable Globally Unique IDs
umbrella - ⛱ Broadly scoped ecosystem & mono-repository of 192 TypeScript projects (and 157 examples) for general purpose, functional, data driven development
pg_tle - Framework for building trusted language extensions for PostgreSQL