feat: refactoring use memory

Author: arturmon

analytics.go

@@ -2,21 +2,31 @@ package multi_tier_caching
 
 import (
 	"sync"
+	"time"
 )
 
 type CacheAnalytics struct {
-	hits, misses int
-	mu           sync.Mutex
+	hits, misses  int
+	frequencies   map[string]int // Request frequency for each keyword
+	recentFreq    sync.Map       // Request frequency in the last minute
+	mu            sync.Mutex
+	lastResetTime time.Time
 }
 
 func NewCacheAnalytics() *CacheAnalytics {
-	return &CacheAnalytics{}
+	return &CacheAnalytics{
+		frequencies:   make(map[string]int),
+		lastResetTime: time.Now(),
+	}
 }
 
-func (ca *CacheAnalytics) LogHit() {
+func (ca *CacheAnalytics) LogHit(key string) {
 	ca.mu.Lock()
 	defer ca.mu.Unlock()
 	ca.hits++
+	ca.frequencies[key]++
+	valRecent, _ := ca.recentFreq.LoadOrStore(key, 0)
+	ca.recentFreq.Store(key, valRecent.(int)+1)
 }
 
 func (ca *CacheAnalytics) LogMiss() {
@@ -30,3 +40,56 @@ func (ca *CacheAnalytics) GetStats() (int, int) {
 	defer ca.mu.Unlock()
 	return ca.hits, ca.misses
 }
+
+func (ca *CacheAnalytics) GetFrequency(key string) int {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	return ca.frequencies[key]
+}
+
+// GetTotalFrequency Returns the total number of times a key has been accessed.
+func (ca *CacheAnalytics) GetTotalFrequency(key string) int {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+	return ca.frequencies[key]
+}
+
+// GetFrequencyPerMinute Returns the request rate per minute and resets the counters
+func (ca *CacheAnalytics) GetFrequencyPerMinute() map[string]int {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+
+	now := time.Now()
+	if now.Sub(ca.lastResetTime).Minutes() < 1 {
+		return nil // Not a minute has passed yet
+	}
+
+	freqCopy := make(map[string]int)
+	// Iterating over the sync.Map using Range
+	ca.recentFreq.Range(func(k, v interface{}) bool {
+		if key, ok := k.(string); ok {
+			if count, ok := v.(int); ok {
+				freqCopy[key] = count
+			}
+		}
+		return true // continue iteration
+	})
+
+	// Resetting temporary data
+	ca.recentFreq = sync.Map{}
+	ca.lastResetTime = now
+
+	return freqCopy
+}
+
+// ResetFrequencies We reset the counters every minute
+func (ca *CacheAnalytics) ResetFrequencies() {
+	ca.mu.Lock()
+	defer ca.mu.Unlock()
+
+	now := time.Now()
+	if now.Sub(ca.lastResetTime).Minutes() >= 1 {
+		ca.frequencies = make(map[string]int) // Clearing the counters
+		ca.lastResetTime = now
+	}
+}

cache.go

@@ -10,61 +10,126 @@ import (
 var ErrCacheMiss = errors.New("cache miss")
 
 type MultiTierCache struct {
-	layers      []CacheLayer
-	db          Database
-	bloomFilter *BloomFilter
-	writeQueue  *WriteQueue
-	analytics   *CacheAnalytics
-	ttlManager  *TTLManager
+	layers         []CacheLayer // Cache layers sorted from hot to cold
+	db             Database
+	bloomFilter    *BloomFilter
+	writeQueue     *WriteQueue
+	analytics      *CacheAnalytics
+	ttlManager     *TTLManager
+	freqThresholds []int // Request rate thresholds for transition between layers
 }
 
-func NewMultiTierCache(layers []CacheLayer, db Database) *MultiTierCache {
-	return &MultiTierCache{
-		layers:      layers,
-		db:          db,
-		bloomFilter: NewBloomFilter(1000000, 5),
-		writeQueue:  NewWriteQueue(func(task WriteTask) { _ = db.Set(context.Background(), task.Key, task.Value, 0) }),
-		analytics:   NewCacheAnalytics(),
-		ttlManager:  NewTTLManager(),
+func NewMultiTierCache(layers []CacheLayer, db Database, thresholds []int) *MultiTierCache {
+	cache := &MultiTierCache{
+		layers:         layers,
+		db:             db,
+		bloomFilter:    NewBloomFilter(1000000, 5),
+		writeQueue:     NewWriteQueue(func(task WriteTask) { _ = db.Set(context.Background(), task.Key, task.Value, 0) }),
+		analytics:      NewCacheAnalytics(),
+		ttlManager:     NewTTLManager(),
+		freqThresholds: thresholds,
 	}
+
+	// Starting a background process to clean frequencies
+	go func() {
+		for {
+			time.Sleep(60 * time.Second)
+			cache.analytics.ResetFrequencies()
+		}
+	}()
+
+	return cache
 }
 
 func (c *MultiTierCache) Get(ctx context.Context, key string) (string, error) {
+	// Searching in cache layers
 	for _, layer := range c.layers {
 		value, err := layer.Get(ctx, key)
 		if err == nil {
-			c.analytics.LogHit()
+			c.analytics.LogHit(key) // Logging a hit with a key
 			return value, nil
 		}
 	}
-
+	// Checking in Bloom filter
 	if !c.bloomFilter.Exists(key) {
 		c.analytics.LogMiss()
 		return "", ErrCacheMiss
 	}
-
+	// Getting from DB
 	value, err := c.db.Get(ctx, key)
 	if err != nil {
 		return "", err
 	}
 
-	err = c.Set(ctx, key, value)
+	// Defining target layers based on frequency
+	freq := c.analytics.GetFrequency(key)
+	targetLayers := c.selectTargetLayers(freq)
+
+	// Update cache only in selected layers
+	err = c.updateLayers(ctx, key, value, targetLayers)
 	if err != nil {
 		return "", err
 	}
+
 	c.bloomFilter.Add(key)
 	return value, nil
 }
 
 func (c *MultiTierCache) Set(ctx context.Context, key, value string) error {
-	ttl := c.ttlManager.AdjustTTL(key)
+	freq := c.analytics.GetFrequency(key)
+	ttl := c.calculateAdaptiveTTL(freq) // New Method for Adaptive TTL
 	ttlSeconds := time.Duration(ttl) * time.Second
+
 	for _, layer := range c.layers {
 		err := layer.Set(ctx, key, value, ttlSeconds)
 		if err != nil {
 			return err
 		}
 	}
+
+	c.writeQueue.Enqueue(WriteTask{Key: key, Value: value})
+	return nil
+}
+
+func (c *MultiTierCache) selectTargetLayers(freq int) []CacheLayer {
+	var layers []CacheLayer
+
+	// Adaptive movement: frequently requested data stays in fast layers
+	for i := len(c.freqThresholds) - 1; i >= 0; i-- {
+		if freq >= c.freqThresholds[i] {
+			layers = append(layers, c.layers[i])
+		}
+	}
+	return layers
+}
+
+func (c *MultiTierCache) updateLayers(ctx context.Context, key, value string, targetLayers []CacheLayer) error {
+	ttl := c.ttlManager.AdjustTTL(key)
+	ttlSeconds := time.Duration(ttl) * time.Second
+
+	// We update only target layers
+	for _, layer := range targetLayers {
+		if err := layer.Set(ctx, key, value, ttlSeconds); err != nil {
+			return err
+		}
+	}
+
+	// Clearing the key from layers not included in the target
+	for _, layer := range c.layers {
+		if !containsLayer(targetLayers, layer) {
+			layer.Delete(ctx, key)
+		}
+	}
+
 	c.writeQueue.Enqueue(WriteTask{Key: key, Value: value})
 	return nil
 }
+
+func containsLayer(layers []CacheLayer, target CacheLayer) bool {
+	for _, l := range layers {
+		if l == target {
+			return true
+		}
+	}
+	return false
+}

go.mod

@@ -4,26 +4,29 @@ go 1.23.1
 
 require (
 	github.com/bits-and-blooms/bloom/v3 v3.7.0
-	github.com/bradfitz/gomemcache v0.0.0-20230905024940-24af94b03874
+	github.com/dgraph-io/ristretto v0.2.0
 	github.com/jackc/pgx/v5 v5.7.2
 	github.com/redis/go-redis/v9 v9.7.0
-	github.com/stretchr/testify v1.8.1
+	github.com/stretchr/testify v1.8.4
 )
 
 require (
 	github.com/bits-and-blooms/bitset v1.10.0 // indirect
 	github.com/cespare/xxhash/v2 v2.2.0 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f // indirect
+	github.com/dustin/go-humanize v1.0.1 // indirect
 	github.com/jackc/pgpassfile v1.0.0 // indirect
 	github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 // indirect
 	github.com/jackc/puddle/v2 v2.2.2 // indirect
 	github.com/kr/text v0.2.0 // indirect
+	github.com/pkg/errors v0.9.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
 	github.com/rogpeppe/go-internal v1.13.1 // indirect
 	github.com/stretchr/objx v0.5.0 // indirect
 	golang.org/x/crypto v0.31.0 // indirect
 	golang.org/x/sync v0.10.0 // indirect
+	golang.org/x/sys v0.28.0 // indirect
 	golang.org/x/text v0.21.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )

go.sum

@@ -2,8 +2,6 @@ github.com/bits-and-blooms/bitset v1.10.0 h1:ePXTeiPEazB5+opbv5fr8umg2R/1NlzgDsy
 github.com/bits-and-blooms/bitset v1.10.0/go.mod h1:7hO7Gc7Pp1vODcmWvKMRA9BNmbv6a/7QIWpPxHddWR8=
 github.com/bits-and-blooms/bloom/v3 v3.7.0 h1:VfknkqV4xI+PsaDIsoHueyxVDZrfvMn56jeWUzvzdls=
 github.com/bits-and-blooms/bloom/v3 v3.7.0/go.mod h1:VKlUSvp0lFIYqxJjzdnSsZEw4iHb1kOL2tfHTgyJBHg=
-github.com/bradfitz/gomemcache v0.0.0-20230905024940-24af94b03874 h1:N7oVaKyGp8bttX0bfZGmcGkjz7DLQXhAn3DNd3T0ous=
-github.com/bradfitz/gomemcache v0.0.0-20230905024940-24af94b03874/go.mod h1:r5xuitiExdLAJ09PR7vBVENGvp4ZuTBeWTGtxuX3K+c=
 github.com/bsm/ginkgo/v2 v2.12.0 h1:Ny8MWAHyOepLGlLKYmXG4IEkioBysk6GpaRTLC8zwWs=
 github.com/bsm/ginkgo/v2 v2.12.0/go.mod h1:SwYbGRRDovPVboqFv0tPTcG1sN61LM1Z4ARdbAV9g4c=
 github.com/bsm/gomega v1.27.10 h1:yeMWxP2pV2fG3FgAODIY8EiRE3dy0aeFYt4l7wh6yKA=
@@ -14,8 +12,14 @@ github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ3
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/dgraph-io/ristretto v0.2.0 h1:XAfl+7cmoUDWW/2Lx8TGZQjjxIQ2Ley9DSf52dru4WE=
+github.com/dgraph-io/ristretto v0.2.0/go.mod h1:8uBHCU/PBV4Ag0CJrP47b9Ofby5dqWNh4FicAdoqFNU=
+github.com/dgryski/go-farm v0.0.0-20200201041132-a6ae2369ad13 h1:fAjc9m62+UWV/WAFKLNi6ZS0675eEUC9y3AlwSbQu1Y=
+github.com/dgryski/go-farm v0.0.0-20200201041132-a6ae2369ad13/go.mod h1:SqUrOPUnsFjfmXRMNPybcSiG0BgUW2AuFH8PAnS2iTw=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f h1:lO4WD4F/rVNCu3HqELle0jiPLLBs70cWOduZpkS1E78=
 github.com/dgryski/go-rendezvous v0.0.0-20200823014737-9f7001d12a5f/go.mod h1:cuUVRXasLTGF7a8hSLbxyZXjz+1KgoB3wDUb6vlszIc=
+github.com/dustin/go-humanize v1.0.1 h1:GzkhY7T5VNhEkwH0PVJgjz+fX1rhBrR7pRT3mDkpeCY=
+github.com/dustin/go-humanize v1.0.1/go.mod h1:Mu1zIs6XwVuF/gI1OepvI0qD18qycQx+mFykh5fBlto=
 github.com/jackc/pgpassfile v1.0.0 h1:/6Hmqy13Ss2zCq62VdNG8tM1wchn8zjSGOBJ6icpsIM=
 github.com/jackc/pgpassfile v1.0.0/go.mod h1:CEx0iS5ambNFdcRtxPj5JhEz+xB6uRky5eyVu/W2HEg=
 github.com/jackc/pgservicefile v0.0.0-20240606120523-5a60cdf6a761 h1:iCEnooe7UlwOQYpKFhBabPMi4aNAfoODPEFNiAnClxo=
@@ -28,6 +32,8 @@ github.com/kr/pretty v0.3.0 h1:WgNl7dwNpEZ6jJ9k1snq4pZsg7DOEN8hP9Xw0Tsjwk0=
 github.com/kr/pretty v0.3.0/go.mod h1:640gp4NfQd8pI5XOwp5fnNeVWj67G7CFk/SaSQn7NBk=
 github.com/kr/text v0.2.0 h1:5Nx0Ya0ZqY2ygV366QzturHI13Jq95ApcVaJBhpS+AY=
 github.com/kr/text v0.2.0/go.mod h1:eLer722TekiGuMkidMxC/pM04lWEeraHUUmBw8l2grE=
+github.com/pkg/errors v0.9.1 h1:FEBLx1zS214owpjy7qsBeixbURkuhQAwrK5UwLGTwt4=
+github.com/pkg/errors v0.9.1/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/redis/go-redis/v9 v9.7.0 h1:HhLSs+B6O021gwzl+locl0zEDnyNkxMtf/Z3NNBMa9E=
@@ -42,14 +48,16 @@ github.com/stretchr/testify v1.3.0/go.mod h1:M5WIy9Dh21IEIfnGCwXGc5bZfKNJtfHm1UV
 github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.7.1/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg=
 github.com/stretchr/testify v1.8.0/go.mod h1:yNjHg4UonilssWZ8iaSj1OCr/vHnekPRkoO+kdMU+MU=
-github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
-github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
+github.com/stretchr/testify v1.8.4 h1:CcVxjf3Q8PM0mHUKJCdn+eZZtm5yQwehR5yeSVQQcUk=
+github.com/stretchr/testify v1.8.4/go.mod h1:sz/lmYIOXD/1dqDmKjjqLyZ2RngseejIcXlSw2iwfAo=
 github.com/twmb/murmur3 v1.1.6 h1:mqrRot1BRxm+Yct+vavLMou2/iJt0tNVTTC0QoIjaZg=
 github.com/twmb/murmur3 v1.1.6/go.mod h1:Qq/R7NUyOfr65zD+6Q5IHKsJLwP7exErjN6lyyq3OSQ=
 golang.org/x/crypto v0.31.0 h1:ihbySMvVjLAeSH1IbfcRTkD/iNscyz8rGzjF/E5hV6U=
 golang.org/x/crypto v0.31.0/go.mod h1:kDsLvtWBEx7MV9tJOj9bnXsPbxwJQ6csT/x4KIN4Ssk=
 golang.org/x/sync v0.10.0 h1:3NQrjDixjgGwUOCaF8w2+VYHv0Ve/vGYSbdkTa98gmQ=
 golang.org/x/sync v0.10.0/go.mod h1:Czt+wKu1gCyEFDUtn0jG5QVvpJ6rzVqr5aXyt9drQfk=
+golang.org/x/sys v0.28.0 h1:Fksou7UEQUWlKvIdsqzJmUmCX3cZuD2+P3XyyzwMhlA=
+golang.org/x/sys v0.28.0/go.mod h1:/VUhepiaJMQUp4+oa/7Zr1D23ma6VTLIYjOOTFZPUcA=
 golang.org/x/text v0.21.0 h1:zyQAAkrwaneQ066sspRyJaG9VNi/YJ1NfzcGB3hZ/qo=
 golang.org/x/text v0.21.0/go.mod h1:4IBbMaMmOPCJ8SecivzSH54+73PCFmPWxNTLm+vZkEQ=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=