Overview

doublejump 的核心是 Google Jump 一致性哈希算法，这个实现弥补了该算法的最大缺点：不能删除节点。

传送门

https://github.com/edwingeng/doublejump

Benchmark

BenchmarkDoubleJumpWithoutLock/10-nodes      50000000     27.6 ns/op
BenchmarkDoubleJumpWithoutLock/100-nodes     30000000     42.7 ns/op
BenchmarkDoubleJumpWithoutLock/1000-nodes    30000000     54.1 ns/op

BenchmarkDoubleJump/10-nodes                 20000000     72.9 ns/op
BenchmarkDoubleJump/100-nodes                20000000     86.1 ns/op
BenchmarkDoubleJump/1000-nodes               20000000     97.9 ns/op

BenchmarkStathatConsistent/10-nodes           5000000    301 ns/op
BenchmarkStathatConsistent/100-nodes          5000000    334 ns/op
BenchmarkStathatConsistent/1000-nodes         3000000    444 ns/op

BenchmarkSerialxHashring/10-nodes             5000000    280 ns/op
BenchmarkSerialxHashring/100-nodes            5000000    340 ns/op
BenchmarkSerialxHashring/1000-nodes           3000000    427 ns/op

Example

h := NewHash()
for i := 0; i < 10; i++ {
    h.Add(fmt.Sprintf("node%d", i))
}

fmt.Println(h.Len())
fmt.Println(h.LooseLen())

fmt.Println(h.Get(1000))
fmt.Println(h.Get(2000))
fmt.Println(h.Get(3000))

h.Remove("node3")
fmt.Println(h.Len())
fmt.Println(h.LooseLen())

fmt.Println(h.Get(1000))
fmt.Println(h.Get(2000))
fmt.Println(h.Get(3000))

// Output:
// 10
// 10
// node9
// node2
// node3
// 9
// 10
// node9
// node2
// node0