#W-TinyLFU (Windowed TinyLFU) Cache

W-TinyLFU is a windowed TinyLFU with sliding window.

#Overview

W-TinyLFU (Windowed TinyLFU) adds a sliding window mechanism to TinyLFU. It uses a time window to track access frequency, better handling time-based access patterns and periodic data access.

#Features

• Hit Rate: 90%
• Memory Usage: Medium
• Concurrency: High
• Implementation Complexity: Complex

#Use Cases

• Time-based access patterns
• Periodic data access
• Sliding window requirements
• Scenarios requiring time window statistics

#Quick Start

#Installation

go get github.com/lazygophers/utils/cache/wtinylfu

#Basic Usage

package main

import (
    "fmt"
    "github.com/lazygophers/utils/cache/wtinylfu"
)

func main() {
    // Create cache with capacity of 1000, window size of 100
    cache := wtinylfu.New(1000, 100)

    // Set values
    cache.Set("key1", "value1")
    cache.Set("key2", "value2")

    // Get values
    if value, ok := cache.Get("key1"); ok {
        fmt.Println("Found:", value)
    }

    // Delete values
    cache.Delete("key1")

    // Clear cache
    cache.Clear()
}

#How It Works

W-TinyLFU uses a sliding window:

Time Window
┌────────────────────────────┐
│  [access1, access2, ...]    │  ← Inside window
│  [access1, access2, ...]    │  ← Outside window
└────────────────────────────┘
    ↑ Window slides

Accesses within the window are used to calculate frequency, accesses outside the window gradually decay.

#API Reference

#Constructors

// Create new W-TinyLFU cache
func New(capacity int, windowSize int) *WTinyLFU

// Create new W-TinyLFU cache with options
func NewWithOpts(opts Options) *WTinyLFU

#Main Methods

// Set key-value pair
func (c *WTinyLFU) Set(key string, value interface{})

// Get value
func (c *WTinyLFU) Get(key string) (interface{}, bool)

// Delete key
func (c *WTinyLFU) Delete(key string)

// Clear cache
func (c *WTinyLFU) Clear()

// Get statistics
func (c *WTinyLFU) Stats() Stats

#Performance Characteristics

• Time Complexity:
  • Set: O(1) average
  • Get: O(1) average
  • Delete: O(1)
• Space Complexity: O(n), where n is cache capacity

#Best Practices

1. Choose appropriate window size: Adjust window size based on access patterns
2. Periodic access: W-TinyLFU is particularly suitable for periodic access patterns
3. Time window statistics: Suitable for scenarios requiring time window statistics

#Related Documentation

• Cache Overview
• TinyLFU Cache
• Cache Selection Guide