111 lines
2.5 KiB
Go
111 lines
2.5 KiB
Go
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/*
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Copyright 2013 Google Inc.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package consistenthash
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import (
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"fmt"
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"strconv"
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"testing"
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)
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func TestHashing(t *testing.T) {
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// Override the hash function to return easier to reason about values. Assumes
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// the keys can be converted to an integer.
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hash := New(3, func(key []byte) uint32 {
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i, err := strconv.Atoi(string(key))
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if err != nil {
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panic(err)
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}
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return uint32(i)
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})
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// Given the above hash function, this will give replicas with "hashes":
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// 2, 4, 6, 12, 14, 16, 22, 24, 26
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hash.Add("6", "4", "2")
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testCases := map[string]string{
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"2": "2",
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"11": "2",
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"23": "4",
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"27": "2",
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}
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for k, v := range testCases {
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if hash.Get(k) != v {
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t.Errorf("Asking for %s, should have yielded %s", k, v)
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}
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}
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// Adds 8, 18, 28
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hash.Add("8")
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// 27 should now map to 8.
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testCases["27"] = "8"
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for k, v := range testCases {
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if hash.Get(k) != v {
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t.Errorf("Asking for %s, should have yielded %s", k, v)
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}
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}
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}
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func TestConsistency(t *testing.T) {
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hash1 := New(1, nil)
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hash2 := New(1, nil)
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hash1.Add("Bill", "Bob", "Bonny")
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hash2.Add("Bob", "Bonny", "Bill")
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if hash1.Get("Ben") != hash2.Get("Ben") {
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t.Errorf("Fetching 'Ben' from both hashes should be the same")
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}
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hash2.Add("Becky", "Ben", "Bobby")
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if hash1.Get("Ben") != hash2.Get("Ben") ||
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hash1.Get("Bob") != hash2.Get("Bob") ||
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hash1.Get("Bonny") != hash2.Get("Bonny") {
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t.Errorf("Direct matches should always return the same entry")
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}
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}
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func BenchmarkGet8(b *testing.B) { benchmarkGet(b, 8) }
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func BenchmarkGet32(b *testing.B) { benchmarkGet(b, 32) }
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func BenchmarkGet128(b *testing.B) { benchmarkGet(b, 128) }
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func BenchmarkGet512(b *testing.B) { benchmarkGet(b, 512) }
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func benchmarkGet(b *testing.B, shards int) {
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hash := New(50, nil)
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var buckets []string
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for i := 0; i < shards; i++ {
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buckets = append(buckets, fmt.Sprintf("shard-%d", i))
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}
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hash.Add(buckets...)
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b.ResetTimer()
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for i := 0; i < b.N; i++ {
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hash.Get(buckets[i&(shards-1)])
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}
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}
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