README
¶
cache
LRU: 最近没使用的换出缓存，go routine安全
接口LRUFacade
// Get returns a value from the cache, and marks the entry as most recently used.
Get(key interface{}) (v Value, ok bool)
// Peek returns a value from the cache without changing the LRU order.
Peek(key interface{}) (v Value, ok bool)
// Set sets a value in the cache.
Set(key interface{}, value Value)
// Delete removes an entry from the cache, and returns if the entry existed.
Delete(key interface{}) bool
//创建容量为10000的单个LRU Cache
var s = NewSingleLRUCache(10000)
//创建容量为20000的多路LRU Cache
var m = NeWideLRUCache(20000)
//创建容量为20000的多路LRU Cache
//并通过remap.WithPrime(211)明确指定将Cache分成211组
//需要传入一个素数让分组更均匀
var m = NeWideLRUCache(20000, remap.WithPrime(211))
//创建容量为30000的多路LRU Cache，其中在对key做映射时，
//对key做xxhash运算然后用求的的uint64值来计算它对应多路Cache中具体哪一个。
var x = NeWideLRUCache(20000)
Map: 对Map进行了读写锁的封装，go routine安全
接口MapFacade
//MapFacade an interface to define a Map
type MapFacade interface {
//Set : set key-value
Set(key interface{}, value interface{})
//Get : get value
Get(key interface{}) (interface{}, bool)
//Exist : return true if key in map
Exist(key interface{}) bool
//Delete : delete a key
Delete(key interface{})
}
//创建单个Map
var s = NewSingleMap()
//创建容多路Map
var m = NeWideMap()
//创建多路Map
//并通过remap.WithPrime(211)明确指定将Cache分成211组
//需要传入一个素数让分组更均匀
var m = NeWideMap(remap.WithPrime(211))
//创建多路Map，其中在对key做映射时，
//对key做xxhash运算然后用求的的uint64值来计算它对应多路Cache中具体哪一个。
var x = NewWideXHashMap()
特别说明
对LRU和Map进行分组能提高至少一倍的效率，但就算使用单个Map或LRU本身的效率也非常高，可以根据具体的场景来取舍。
LRU的读写测试大概耗时为300ns，分组LRU大概耗时为130ns。
Map的读写测试大概耗时为150ns，分组Map大概耗时为50ns。
Documentation
¶
Overview ¶
Package cache implements a LRU cache.
The implementation borrows heavily from SmallLRUCache (originally by Nathan Schrenk). The object maintains a doubly-linked list of elements. When an element is accessed, it is promoted to the head of the list. When space is needed, the element at the tail of the list (the least recently used element) is evicted.
Index ¶
- Variables
- type GetOptFn
- type Item
- type LRUCache
- func (lru *LRUCache) Capacity() int64
- func (lru *LRUCache) Clear()
- func (lru *LRUCache) Delete(key interface{}) bool
- func (lru *LRUCache) Evictions() int64
- func (lru *LRUCache) Get(key interface{}) (v Value, ok bool)
- func (lru *LRUCache) Init(capacity int64)
- func (lru *LRUCache) Items() []Item
- func (lru *LRUCache) Keys() []interface{}
- func (lru *LRUCache) Length() int64
- func (lru *LRUCache) Peek(key interface{}) (v Value, ok bool)
- func (lru *LRUCache) Set(key interface{}, value Value)
- func (lru *LRUCache) SetAndGetRemoved(key interface{}, value Value) (removedValueList []Value)
- func (lru *LRUCache) SetCapacity(capacity int64)
- func (lru *LRUCache) SetIfAbsent(key interface{}, value Value)
- func (lru *LRUCache) Size() int64
- func (lru *LRUCache) Stats() (length, size, capacity, evictions int64)
- func (lru *LRUCache) StatsJSON() string
- type LRUFacade
- type Map
- type MapFacade
- type SetOptFn
- type TTLCache
- type Value
- type WideLRUCache
- type WideMap
Constants ¶
This section is empty.
Variables ¶
var ( // ErrTTLKeyExists When key exists will return this error. ErrTTLKeyExists = status.Error(codes.AlreadyExists, "ttl.key.exists") // ErrTTLKeyNotFound When key not found will return this error. ErrTTLKeyNotFound = status.Error(codes.NotFound, "ttl.key.not.found") )
Functions ¶
This section is empty.
Types ¶
type GetOptFn ¶ added in v0.8.1
type GetOptFn func(*getOption)
func WithRemoveAfterGet ¶ added in v0.8.1
func WithRemoveAfterGet() GetOptFn
func WithUpdateTTL ¶ added in v0.8.3
type LRUCache ¶
type LRUCache struct {
// contains filtered or unexported fields
}
LRUCache is a typical LRU cache implementation. If the cache reaches the capacity, the least recently used item is deleted from the cache. Note the capacity is not the number of items, but the total sum of the Size() of each item.
func NewLRUCache ¶
NewLRUCache creates a new empty cache with the given capacity.
func (*LRUCache) Get ¶
Get returns a value from the cache, and marks the entry as most recently used.
func (*LRUCache) Items ¶
Items returns all the values for the cache, ordered from most recently used to last recently used.
func (*LRUCache) Keys ¶
func (lru *LRUCache) Keys() []interface{}
Keys returns all the keys for the cache, ordered from most recently used to last recently used.
func (*LRUCache) SetAndGetRemoved ¶
SetAndGetRemoved sets a value in the cache and returns the removed value list
func (*LRUCache) SetCapacity ¶
SetCapacity will set the capacity of the cache. If the capacity is smaller, and the current cache size exceed that capacity, the cache will be shrank.
func (*LRUCache) SetIfAbsent ¶
SetIfAbsent will set the value in the cache if not present. If the value exists in the cache, we don't set it.
type LRUFacade ¶ added in v0.2.7
type LRUFacade interface {
// Get returns a value from the cache, and marks the entry as most recently used.
Get(key interface{}) (v Value, ok bool)
// Peek returns a value from the cache without changing the LRU order.
Peek(key interface{}) (v Value, ok bool)
// Set sets a value in the cache.
Set(key interface{}, value Value)
// Delete removes an entry from the cache, and returns if the entry existed.
Delete(key interface{}) bool
}
LRUFacade an interface to define a LRU cache
func NeWideLRUCache ¶ added in v0.2.7
NeWideLRUCache new wide lru cache
func NewSingleLRUCache ¶ added in v0.2.7
NewSingleLRUCache create a single lru cache
type MapFacade ¶ added in v0.2.7
type MapFacade interface {
//Set : set key-value
Set(key interface{}, value interface{})
//Get : get value
Get(key interface{}) (interface{}, bool)
//Exist : return true if key in map
Exist(key interface{}) bool
//Delete : delete a key
Delete(key interface{})
}
MapFacade an interface to define a Map
func NewWideMap ¶ added in v0.2.8
NewWideMap new wide Map
func NewWideXHashMap ¶ added in v0.2.7
NewWideXHashMap new wide Map use xxhash as group
type SetOptFn ¶ added in v0.8.1
type SetOptFn func(*setOption)
func WithKeepTTL ¶ added in v0.8.3
func WithKeepTTL() SetOptFn
func WithMustNotExist ¶ added in v0.8.1
func WithMustNotExist() SetOptFn
type TTLCache ¶ added in v0.8.0
type TTLCache interface {
// Set key value into ttl cache.
Set(ctx context.Context, key string, value []byte, fns ...SetOptFn) error
// Get value by key from ttl cache.
Get(ctx context.Context, key string, fns ...GetOptFn) ([]byte, error)
// Remove value by key.
Remove(ctx context.Context, key string) error
// Clear cache.
Clear(ctx context.Context)
}
func NewTTLMemCache ¶ added in v0.8.2
NewTTLMemCache New ttl cache
func NewTTLRdsCache ¶ added in v0.8.2
type Value ¶
type Value interface {
// Size returns how big this value is. If you want to just track
// the cache by number of objects, you may return the size as 1.
Size() int
}
Value is the interface values that go into LRUCache need to satisfy
type WideLRUCache ¶ added in v0.2.7
type WideLRUCache struct {
// contains filtered or unexported fields
}
WideLRUCache use LruCache group array as a wide lru cache
func (*WideLRUCache) Delete ¶ added in v0.2.7
func (w *WideLRUCache) Delete(key interface{}) bool
Delete removes an entry from the cache, and returns if the entry existed.
func (*WideLRUCache) Get ¶ added in v0.2.7
func (w *WideLRUCache) Get(key interface{}) (v Value, ok bool)
Get returns a value from the cache, and marks the entry as most recently used.
func (*WideLRUCache) Peek ¶ added in v0.2.7
func (w *WideLRUCache) Peek(key interface{}) (v Value, ok bool)
Peek returns a value from the cache without changing the LRU order.
func (*WideLRUCache) Set ¶ added in v0.2.7
func (w *WideLRUCache) Set(key interface{}, value Value)
Set sets a value in the cache.
type WideMap ¶ added in v0.2.7
type WideMap struct {
// contains filtered or unexported fields
}
WideMap use Map group array as a wide map
func (*WideMap) Delete ¶ added in v0.2.7
func (w *WideMap) Delete(key interface{})
Delete : delete a key
Source Files