README
¶
LFU Cache
LFU cache in Go offering O(1) Get and Insert outlined here.
Install
go get -u github.com/mtchavez/lfu
Usage
package main
import (
"fmt"
"github.com/mtchavez/lfu"
)
func main() {
cache := lfu.NewLFU()
// Insert
cache.Insert(42, []byte("user:42:user@example.com"))
// Insert existing key
success, err := cache.Insert(42, "Nope")
if !success {
fmt.Println("Error inserting:", err)
}
var data interface{}
var e error
// Get
data, e = cache.Get(42)
fmt.Println("Data for 42 is", data)
// Get not found
data, e = cache.Get(987654321)
if e != nil {
fmt.Println("Error on get:", e)
}
}
Tests
go test --cover
Benhcmarks
Get and insert methods are benchmarked. Results from OS X with
a 2.3 GHz Intel Core i7 on go version go1.8.3 darwin/amd64
# Updated: 2017-08-15
BenchmarkInsert-8 1000000 1860 ns/op
BenchmarkParallelInsert-8 1000000 1861 ns/op
BenchmarkGet_EmptyCache-8 5000000 362 ns/op
BenchmarkGet_AllMisses-8 3000000 732 ns/op
BenchmarkGet_AllHits-8 1000000 1417 ns/op
BenchmarkParallelGet-8 2000000 1405 ns/op
TODO
- Some kind of eviction
Documentation
¶
Index ¶
Examples ¶
Constants ¶
This section is empty.
Variables ¶
This section is empty.
Functions ¶
This section is empty.
Types ¶
type Cache ¶
Cache used to call core cache methods off of
func (*Cache) Get ¶
Get takes a key for an item in the cache to look up Returns the data associated with that key and an
Example ¶
cache := NewLFU()
cache.Insert(1, []byte("user:1:aeb31da42fae09afqld"))
// Get key 1
data, _ := cache.Get(1)
fmt.Println("Cached data for key 1:", string(reflect.ValueOf(data).Bytes()))
// Get a not cached key
_, err := cache.Get(42)
fmt.Println("Failed get:", err)
Output: Cached data for key 1: user:1:aeb31da42fae09afqld Failed get: Key: 42 not found in cache
func (*Cache) GetLFUItem ¶
func (c *Cache) GetLFUItem() (value interface{}, data interface{})
GetLFUItem returns the key and data of the least frequently updated item in the cache or -1 and nil for not found
func (*Cache) Insert ¶
Insert takes a key and a value to insert into the cache Returns a boolean for successful insert and an error if failed
Example ¶
cache := NewLFU()
inserted, _ := cache.Insert(1, []byte("user:1:aeb31da42fae09afqld"))
fmt.Println("Inserted:", inserted)
// Insert existing key
_, err := cache.Insert(1, "boom")
fmt.Println("Insert error:", err)
Output: Inserted: true Insert error: Key already exists in cache
Source Files
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