Once is an Ecto type for locally unique (unique within your domain or application) 64-bit IDs generated by multiple Elixir nodes. Locally unique IDs make it easier to keep things separated, simplify caching and simplify inserting related things (because you don’t have to wait for the database to return the ID).
Because a Once fits into an SQL bigint, they use little space and keep indexes small and fast. Because of their structure they have counter-like data locality, which helps your indexes perform well, unlike UUIDv4s.
Once IDs are base on counter, time-sortable or encrypted nonces. These underlying values can then be encoded in several formats, can be prefixed and can be masked. And you can combine all of these options, providing great flexibility.
The library has only Ecto and its sibling NoNoncense as dependencies. NoNoncense generates the actual values and performs incredibly well, hitting rates of tens of millions of nonces per second, and it also helps you to safeguard the uniqueness guarantees.
Package: once | Hex
Source: GitHub - juulSme/Once: Ecto type for 64-bit IDs - prefixed, k-sorted, masked, multiformat, distributed, fast · GitHub
Docs: Once v1.3.1 — Documentation
