https://github.com/go-faster/city
go cityhash implementation
https://github.com/go-faster/city
cityhash go golang hashing
Last synced: about 1 month ago
JSON representation
go cityhash implementation
- Host: GitHub
- URL: https://github.com/go-faster/city
- Owner: go-faster
- License: mit
- Created: 2021-11-17T00:46:40.000Z (over 3 years ago)
- Default Branch: main
- Last Pushed: 2022-08-07T19:39:48.000Z (almost 3 years ago)
- Last Synced: 2025-04-09T19:18:40.598Z (about 1 month ago)
- Topics: cityhash, go, golang, hashing
- Language: Go
- Homepage: https://clickhouse.com/docs/en/native-protocol/hash
- Size: 652 KB
- Stars: 37
- Watchers: 3
- Forks: 3
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# city [](https://pkg.go.dev/github.com/go-faster/city#section-documentation) [](https://codecov.io/gh/go-faster/city) [](https://go-faster.org/docs/projects/status#stable)
[CityHash](https://github.com/google/cityhash) in Go. Fork of [tenfyzhong/cityhash](https://github.com/tenfyzhong/cityhash).
Note: **prefer [xxhash](https://github.com/cespare/xxhash) as non-cryptographic hash algorithm**, this package is intended
for places where CityHash is already used.
CityHash **is not compatible** to [FarmHash](https://github.com/google/farmhash), use [go-farm](https://github.com/dgryski/go-farm).
```console
go get github.com/go-faster/city
```
```go
city.Hash128([]byte("hello"))
```
* Faster
* Supports ClickHouse hash
```
name old time/op new time/op delta
CityHash64-32 333ns ± 2% 108ns ± 3% -67.57% (p=0.000 n=10+10)
CityHash128-32 347ns ± 2% 112ns ± 2% -67.74% (p=0.000 n=9+10)
name old speed new speed delta
CityHash64-32 3.08GB/s ± 2% 9.49GB/s ± 3% +208.40% (p=0.000 n=10+10)
CityHash128-32 2.95GB/s ± 2% 9.14GB/s ± 2% +209.98% (p=0.000 n=9+10)
```
## Examples
Let's take 64-bit hash from `Moscow` string.
```sql
:) SELECT cityHash64('Moscow')
12507901496292878638
```
```go
s := []byte("Moscow")
fmt.Print("ClickHouse: ")
fmt.Println(city.CH64(s))
fmt.Print("CityHash: ")
fmt.Println(city.Hash64(s))
// Output:
// ClickHouse: 12507901496292878638
// CityHash: 5992710078453357409
```
You can use [test data corpus](https://github.com/go-faster/city/blob/main/_testdata/data.json) to check your implementation of ClickHouse CityHash variant if needed.
```json
{
"Seed": {
"Low": 5577006791947779410,
"High": 8674665223082153551
},
"entries": [
{
"Input": "Moscow",
"City32": 431367057,
"City64": 5992710078453357409,
"City128": {
"Low": 10019773792274861915,
"High": 12276543986707912152
},
"City128Seed": {
"Low": 13396466470330251720,
"High": 5508504338941663328
},
"ClickHouse64": 12507901496292878638,
"ClickHouse128": {
"Low": 3377444358654451565,
"High": 2499202049363713365
},
"ClickHouse128Seed": {
"Low": 568168482305327346,
"High": 1719721512326527886
}
}
]
}
```
## Benchmarks
```
goos: linux
goarch: amd64
pkg: github.com/go-faster/city
cpu: AMD Ryzen 9 5950X 16-Core Processor
BenchmarkClickHouse128/16 2213.98 MB/s
BenchmarkClickHouse128/64 4712.24 MB/s
BenchmarkClickHouse128/256 7561.58 MB/s
BenchmarkClickHouse128/1024 10158.98 MB/s
BenchmarkClickHouse64 10379.89 MB/s
BenchmarkCityHash32 3140.54 MB/s
BenchmarkCityHash64 9508.45 MB/s
BenchmarkCityHash128 9304.27 MB/s
BenchmarkCityHash64Small 2700.84 MB/s
BenchmarkCityHash128Small 1175.65 MB/s
```