diff --git a/internal/ttlcache/piece.go b/internal/ttlcache/piece.go
index 40d48c0..2c4251b 100644
--- a/internal/ttlcache/piece.go
+++ b/internal/ttlcache/piece.go
@@ -24,11 +24,19 @@ func NewPiece[T any](maxItems int) *Piece[T] {
 }
 
 func (this *Piece[T]) Add(key uint64, item *Item[T]) (ok bool) {
-	this.locker.Lock()
+	this.locker.RLock()
 	if this.maxItems > 0 && len(this.m) >= this.maxItems {
-		this.locker.Unlock()
+		this.locker.RUnlock()
 		return
 	}
+	this.locker.RUnlock()
+
+	this.locker.Lock()
+	oldItem, exists := this.m[key]
+	if exists && oldItem.expiredAt == item.expiredAt {
+		this.locker.Unlock()
+		return true
+	}
 	this.m[key] = item
 	this.locker.Unlock()
 
diff --git a/internal/ttlcache/piece_test.go b/internal/ttlcache/piece_test.go
index 4605f37..947244b 100644
--- a/internal/ttlcache/piece_test.go
+++ b/internal/ttlcache/piece_test.go
@@ -18,6 +18,16 @@ func TestPiece_Add(t *testing.T) {
 	t.Log(piece.Read(1))
 }
 
+func TestPiece_Add_Same(t *testing.T) {
+	piece := NewPiece[int](10)
+	piece.Add(1, &Item[int]{expiredAt: time.Now().Unix() + 3600})
+	piece.Add(1, &Item[int]{expiredAt: time.Now().Unix() + 3600})
+	for key, item := range piece.m {
+		t.Log(key, item.Value)
+	}
+	t.Log(piece.Read(1))
+}
+
 func TestPiece_MaxItems(t *testing.T) {
 	piece := NewPiece[int](10)
 	for i := 0; i < 1000; i++ {
diff --git a/internal/utils/expires/list_test.go b/internal/utils/expires/list_test.go
index dab6a7c..9a8ae3f 100644
--- a/internal/utils/expires/list_test.go
+++ b/internal/utils/expires/list_test.go
@@ -2,6 +2,7 @@ package expires
 
 import (
 	"github.com/TeaOSLab/EdgeNode/internal/utils/fasttime"
+	"github.com/TeaOSLab/EdgeNode/internal/utils/testutils"
 	"github.com/iwind/TeaGo/assert"
 	"github.com/iwind/TeaGo/logs"
 	timeutil "github.com/iwind/TeaGo/utils/time"
@@ -84,6 +85,10 @@ func TestList_GC_Batch(t *testing.T) {
 }
 
 func TestList_Start_GC(t *testing.T) {
+	if !testutils.IsSingleTesting() {
+		return
+	}
+
 	list := NewList()
 	list.Add(1, time.Now().Unix()+1)
 	list.Add(2, time.Now().Unix()+1)
@@ -125,6 +130,25 @@ func TestList_ManyItems(t *testing.T) {
 	t.Log(time.Since(now))
 }
 
+func TestList_Memory(t *testing.T) {
+	if !testutils.IsSingleTesting() {
+		return
+	}
+
+	var list = NewList()
+
+	testutils.StartMemoryStats(t, func() {
+		t.Log(list.Count(), "items")
+	})
+
+
+	for i := 0; i < 10_000_000; i++ {
+		list.Add(uint64(i), time.Now().Unix()+1800)
+	}
+
+	time.Sleep(1 * time.Hour)
+}
+
 func TestList_Map_Performance(t *testing.T) {
 	t.Log("max uint32", math.MaxUint32)
 
diff --git a/internal/utils/expires/manager.go b/internal/utils/expires/manager.go
index cbbb360..352f25f 100644
--- a/internal/utils/expires/manager.go
+++ b/internal/utils/expires/manager.go
@@ -33,7 +33,7 @@ func (this *Manager) init() {
 	for range this.ticker.C {
 		var currentTime = time.Now().Unix()
 		if lastTimestamp == 0 {
-			lastTimestamp = currentTime - 3600
+			lastTimestamp = currentTime - 86400 // prevent timezone changes
 		}
 
 		if currentTime >= lastTimestamp {