Universally Unique Lexicographically Sortable Identifiers in R
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title: "Introduction to {ulid}"
output: rmarkdown::html_vignette
vignette: >
%\VignetteIndexEntry{Introduction to {ulid}}
```{r, include = FALSE}
collapse = TRUE,
comment = "#>"
## UUID : Universally Unique Lexicographically Sortable Identifiers
UUID can be suboptimal for many uses-cases because:
- It isn't the most character efficient way of encoding 128 bits of randomness
- UUID v1/v2 is impractical in many environments, as it requires access to a unique, stable MAC address
- UUID v3/v5 requires a unique seed and produces randomly distributed IDs, which can cause fragmentation in many data structures
- UUID v4 provides no other information than randomness which can cause fragmentation in many data structures
Instead, herein is proposed ULID:
- 128-bit compatibility with UUID
- 1.21e+24 unique ULIDs per millisecond
- Lexicographically sortable!
- Canonically encoded as a 26 character string, as opposed to the 36 character UUID
- Uses Crockford's base32 for better efficiency and readability (5 bits per character)
- Case insensitive
- No special characters (URL safe)
- Monotonic sort order (correctly detects and handles the same millisecond)
01AN4Z07BY 79KA1307SR9X4MV3
|----------| |----------------|
Timestamp Randomness
48bits 80bits
### Components
- 48 bit integer
- UNIX-time in milliseconds
- Won't run out of space till the year 10889 AD.
- 80 bits
- Cryptographically secure source of randomness, if possible
### Sorting
The left-most character must be sorted first, and the right-most character sorted last (lexical order). The default ASCII character set must be used. Within the same millisecond, sort order is not guaranteed.
## What's Inside The Tin
The following functions are implemented:
- `ULIDgenerate` / `generate` / `ulid_generate`: Generate a time-based ULID
- `ts_generate`: Generate ULID from timestamps
- `unmarshal`: Unmarshal a ULID into a data frame with timestamp and random bitstring columns
```{r setup}
### One
### Many
(u <- ulid::ULIDgenerate(20))
### Unmarshal
### Use defined timestamps
(ut <- ts_generate(as.POSIXct("2017-11-01 15:00:00", origin="1970-01-01")))