https://github.com/creadone/guava
Jump Consistent Hash
https://github.com/creadone/guava
consistent-hashing crystal
Last synced: about 1 year ago
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Jump Consistent Hash
- Host: GitHub
- URL: https://github.com/creadone/guava
- Owner: creadone
- License: mit
- Created: 2023-04-27T18:47:53.000Z (almost 3 years ago)
- Default Branch: master
- Last Pushed: 2023-05-01T23:08:31.000Z (almost 3 years ago)
- Last Synced: 2025-01-02T04:26:39.394Z (about 1 year ago)
- Topics: consistent-hashing, crystal
- Language: C
- Homepage:
- Size: 10.7 KB
- Stars: 1
- Watchers: 1
- Forks: 0
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# Guava
This is a library with a fast and minimal memory-consuming hashing function also known as Jump [Consistent Hash](https://en.wikipedia.org/wiki/Consistent_hashing) from the original work "A Fast, Minimal Memory, Consistent Hash Algorithm" by Google (see [1406.2294v1.pdf](https://arxiv.org/pdf/1406.2294v1.pdf)).
> In comparison to the algorithm of Karger et al., jump consistent hash requires no storage, is faster, and does a better job of evenly dividing the key
space among the buckets and of evenly dividing the workload when the number of buckets changes.
## Installation
Add this to your application's `shard.yml`:
```yaml
dependencies:
guava:
github: creadone/guava
```
Then run `shards install`.
## Usage
```crystal
require "guava"
Guava.jump(7234672323_u64, 12_i32) # => 9
```
## Tests
### Data distribution
```crystal
require "guava"
ary = Array.new(10){ Array.new(1){ 0 } }
values = (0_u64..1_000_000_u64).to_a
values.each do |i|
num = Guava.jump(i, 10_i32)
ary[num].push 0
end
ary.each_with_index do |cell, idx|
puts [idx, cell.size]
end
```
**Result**
| 0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 |
| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- |
| 100001 | 100001 | 100022 | 100004 | 99960 | 100058 | 99945 | 100070 | 99957 | 99992 |
### CPU time to call
> 3,6 GHz Quad-Core Intel Core i3, Mac Mini 2018
```crystal
values = (0_u64..1_000_000_u64).to_a
puts Benchmark.measure {
values.each do |i|
Guava.jump(i, 10_i32)
end
}
```
**Result**
| User CPU | System CPU | Sum of previous | Elapsed real time |
| --------- | --------- | --------- | --------- |
| 0.027966 | 0.000021 | 0.027987 | 0.028015 |
## Contributing
1. Fork it (https://github.com/creadone/guava/fork)
2. Create your feature branch (`git checkout -b my-new-feature`)
3. Commit your changes (`git commit -am 'Add some feature'`)
4. Push to the branch (`git push origin my-new-feature`)
5. Create a new Pull Request
## Contributors
- [creadone](https://github.com/creadone) - creator and maintainer