Overview

• WUID is a unique number generator, but not a UUID implementation.
• WUID is 10-135 times faster than UUID and 4600 times faster than generating unique numbers with Redis.
• WUID generates unique 64-bit integers in sequence. The high 24 bits are loaded from a data store. By now, Redis, MySQL, and MongoDB are supported.

Benchmarks

BenchmarkWUID       100000000           10.3 ns/op         0 B/op          0 allocs/op
BenchmarkRand        50000000           24.6 ns/op         0 B/op          0 allocs/op
BenchmarkTimestamp  100000000           12.3 ns/op         0 B/op          0 allocs/op
BenchmarkUUID_V1     20000000          107 ns/op           0 B/op          0 allocs/op
BenchmarkUUID_V2     20000000          106 ns/op           0 B/op          0 allocs/op
BenchmarkUUID_V3      5000000          359 ns/op         144 B/op          4 allocs/op
BenchmarkUUID_V4      1000000         1376 ns/op          16 B/op          1 allocs/op
BenchmarkUUID_V5      3000000          424 ns/op         176 B/op          4 allocs/op
BenchmarkRedis          30000        46501 ns/op         176 B/op          5 allocs/op
BenchmarkSnowflake    5000000          244 ns/op           0 B/op          0 allocs/op

Features

• Extremely fast
• Thread-safe
• Being unique within a data center
• Being unique across time
• Being unique globally if all data centers share the same data store, or they use different section IDs
• Being capable of generating 100M unique numbers in a single second
• Auto-renew when the low 40 bits are about to run out

Install

go get -u github.com/edwingeng/wuid/...

Or choose one from the following commands if you use dep:

dep ensure -add github.com/edwingeng/wuid/redis
dep ensure -add github.com/edwingeng/wuid/mysql
dep ensure -add github.com/edwingeng/wuid/mongo
dep ensure -add github.com/edwingeng/wuid/callback

Usage examples

Redis

import "github.com/edwingeng/wuid/redis"

// Setup
g := wuid.NewWUID("default", nil)
g.LoadH24FromRedis("127.0.0.1:6379", "", "wuid")

// Generate
for i := 0; i < 10; i++ {
    fmt.Printf("%#016x\n", g.Next())
}

MySQL

import "github.com/edwingeng/wuid/mysql"

// Setup
g := wuid.NewWUID("default", nil)
g.LoadH24FromMysql("127.0.0.1:3306", "root", "", "test", "wuid")

// Generate
for i := 0; i < 10; i++ {
    fmt.Printf("%#016x\n", g.Next())
}

MongoDB

import "github.com/edwingeng/wuid/mongo"

// Setup
g := wuid.NewWUID("default", nil)
g.LoadH24FromMongo("127.0.0.1:27017", "", "", "test", "foo", "wuid")

// Generate
for i := 0; i < 10; i++ {
    fmt.Printf("%#016x\n", g.Next())
}

Callback

import "github.com/edwingeng/wuid/callback"

// Setup
g := wuid.NewWUID("default", nil)
g.LoadH24WithCallback(func() (uint64, error) {
    resp, err := http.Get("https://stackoverflow.com/")
    if resp != nil {
        defer resp.Body.Close()
    }
    if err != nil {
        return 0, err
    }

    bytes, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        return 0, err
    }

    fmt.Printf("Page size: %d (%#06x)\n\n", len(bytes), len(bytes))
    return uint64(len(bytes)), nil
})

// Generate
for i := 0; i < 10; i++ {
    fmt.Printf("%#016x\n", g.Next())
}

Mysql table creation

CREATE TABLE `wuid` (
    `h` int(10) NOT NULL AUTO_INCREMENT,
    `x` tinyint(4) NOT NULL DEFAULT '0',
    PRIMARY KEY (`x`),
    UNIQUE KEY `h` (`h`)
) ENGINE=InnoDB DEFAULT CHARSET=latin1;

Section ID

You can specify a custom section ID for the generated numbers with wuid.WithSection when you call wuid.NewWUID. The section ID must be in between [1, 15]. It occupies the highest 4 bits of the numbers.

Best practices

• Use different keys/tables/docs for different purposes.

Special thanks

• dustinfog