Comments (6)
This is a tricky one to solve 🤔 To work around it I guess you have to prevent concurrent usage by creating a new hasher inside the loop like so:
func TestHashString(t *testing.T) {
- hasher := New(2, fnv.New64a())
input := "123456789"
errCount := make(chan int)
for i := 0; i < 1000; i++ {
go func(i int) {
+ hasher := New(2, fnv.New64a())
res := hasher.Hash(input)
if res != 0 {
errCount <- 1
t.Errorf("hash %d error: res is %d", i, res)
}
}(i)
}
s := 0
go func() {
for j := range errCount {
s += j
}
}()
time.Sleep(1 * time.Second)
fmt.Println("errCount:", s)
}
from go-jump-consistent-hash.
Hopefully fixed by GH-10
from go-jump-consistent-hash.
I use the function:
func HashString(key string, buckets int) int32 {
h := fnv.New64a()
h.Reset()
_, err := io.WriteString(h, key)
if err != nil {
return 0
}
return Hash(h.Sum64(), int32(buckets))
}
func BenchmarkHashStringFNV1a(b *testing.B) {
s := "123456789"
buckets := 2
for i := 0; i < b.N; i++ {
HashString(s, buckets)
}
}
Result:
BenchmarkHashStringFNV1a
BenchmarkHashStringFNV1a-12 17144026 70.3 ns/op
I tested the mutex, little lower.
func BenchmarkHashStringFNV1a2(b *testing.B) {
s := "123456789"
hasher := New(2, FNV1a)
for i := 0; i < b.N; i++ {
hasher.Hash(s)
}
}
benchmark with mutex:
BenchmarkHashStringFNV1a2
BenchmarkHashStringFNV1a2-12 15999657 79.8 ns/op
from go-jump-consistent-hash.
I can only think of two solutions for this problem though:
- Either use a mutex to prevent buffer corruption of the underlying
hash.Hash
object. - Always create a new instance of the
hash.Hash
/KeyHasher
object.
Note that this is only a problem when sharing a hasher between goroutines. Ideally I would like to change the function signature of HashString
like below. It would fix some of the usage errors, but it would also break compatibility which I'm not super keen on:
-func HashString(key string, buckets int32, h KeyHasher) int32 {
+func HashString(key string, buckets int32, h func() KeyHasher) int32 {
from go-jump-consistent-hash.
Also, try using jump.NewFNV1a()
instead of fnv.New64a()
since it's just a thread safe wrapper around the latter.
from go-jump-consistent-hash.
Duplicate of #6
from go-jump-consistent-hash.
Related Issues (3)
Recommend Projects
-
React
A declarative, efficient, and flexible JavaScript library for building user interfaces.
-
Vue.js
🖖 Vue.js is a progressive, incrementally-adoptable JavaScript framework for building UI on the web.
-
Typescript
TypeScript is a superset of JavaScript that compiles to clean JavaScript output.
-
TensorFlow
An Open Source Machine Learning Framework for Everyone
-
Django
The Web framework for perfectionists with deadlines.
-
Laravel
A PHP framework for web artisans
-
D3
Bring data to life with SVG, Canvas and HTML. 📊📈🎉
-
Recommend Topics
-
javascript
JavaScript (JS) is a lightweight interpreted programming language with first-class functions.
-
web
Some thing interesting about web. New door for the world.
-
server
A server is a program made to process requests and deliver data to clients.
-
Machine learning
Machine learning is a way of modeling and interpreting data that allows a piece of software to respond intelligently.
-
Visualization
Some thing interesting about visualization, use data art
-
Game
Some thing interesting about game, make everyone happy.
Recommend Org
-
Facebook
We are working to build community through open source technology. NB: members must have two-factor auth.
-
Microsoft
Open source projects and samples from Microsoft.
-
Google
Google ❤️ Open Source for everyone.
-
Alibaba
Alibaba Open Source for everyone
-
D3
Data-Driven Documents codes.
-
Tencent
China tencent open source team.
from go-jump-consistent-hash.