diff --git a/event_test.go b/event_test.go
index d0a20d0..decdaa4 100644
--- a/event_test.go
+++ b/event_test.go
@@ -3,6 +3,7 @@ package event_emitter
 import (
 	"context"
 	"fmt"
+	"github.com/lxzan/event_emitter/internal/helper"
 	"github.com/stretchr/testify/assert"
 	"sync"
 	"testing"
@@ -102,6 +103,48 @@ func TestEventEmitter_Publish(t *testing.T) {
 			assert.Equal(t, mapping[topic], i+1)
 		}
 	})
+
+	t.Run("batch3", func(t *testing.T) {
+		var em = New(&Config{BucketNum: 1})
+		var count = 1000
+		var mapping1 = make(map[string]int)
+		var mapping2 = make(map[string]int)
+		var mu = &sync.Mutex{}
+		var subjects = make(map[string]uint8)
+		var wg = &sync.WaitGroup{}
+
+		for i := 0; i < count; i++ {
+			var topics []string
+			for j := 0; j < 100; j++ {
+				topic := fmt.Sprintf("topic-%d", helper.Numeric.Intn(count))
+				topics = append(topics, topic)
+			}
+
+			topics = helper.Uniq(topics)
+			wg.Add(len(topics))
+			for j, _ := range topics {
+				var topic = topics[j]
+				mapping1[topic]++
+				subjects[topic] = 1
+				em.Subscribe(int64(i), topic, func(msg any) {
+					mu.Lock()
+					mapping2[topic]++
+					mu.Unlock()
+					wg.Done()
+				})
+			}
+		}
+
+		for k, _ := range subjects {
+			var err = em.Publish(context.Background(), k, "hello")
+			assert.NoError(t, err)
+		}
+
+		wg.Wait()
+		for k, _ := range subjects {
+			assert.Equal(t, mapping1[k], mapping2[k])
+		}
+	})
 }
 
 func TestEventEmitter_UnSubscribe(t *testing.T) {
diff --git a/internal/helper/helper.go b/internal/helper/helper.go
new file mode 100644
index 0000000..e2b7cfc
--- /dev/null
+++ b/internal/helper/helper.go
@@ -0,0 +1,13 @@
+package helper
+
+func Uniq[T comparable](arr []T) []T {
+	var m = make(map[T]struct{}, len(arr))
+	var list = make([]T, 0, len(arr))
+	for _, item := range arr {
+		m[item] = struct{}{}
+	}
+	for k, _ := range m {
+		list = append(list, k)
+	}
+	return list
+}
diff --git a/internal/helper/helper_test.go b/internal/helper/helper_test.go
new file mode 100644
index 0000000..91e2f28
--- /dev/null
+++ b/internal/helper/helper_test.go
@@ -0,0 +1,18 @@
+package helper
+
+import (
+	"github.com/stretchr/testify/assert"
+	"testing"
+)
+
+func TestRandomString(t *testing.T) {
+	assert.Less(t, Numeric.Intn(10), 10)
+	assert.Equal(t, len(AlphabetNumeric.Generate(16)), 16)
+	Numeric.Uint32()
+	Numeric.Uint64()
+}
+
+func TestUniq(t *testing.T) {
+	assert.ElementsMatch(t, Uniq([]int{1, 3, 5, 7, 7, 9}), []int{1, 3, 5, 7, 9})
+	assert.ElementsMatch(t, Uniq([]string{"ming", "ming", "shi"}), []string{"ming", "shi"})
+}
diff --git a/internal/helper/random.go b/internal/helper/random.go
new file mode 100644
index 0000000..46659cf
--- /dev/null
+++ b/internal/helper/random.go
@@ -0,0 +1,60 @@
+package helper
+
+import (
+	"math/rand"
+	"sync"
+	"time"
+)
+
+type RandomString struct {
+	mu     sync.Mutex
+	r      *rand.Rand
+	layout string
+}
+
+var (
+	AlphabetNumeric = &RandomString{
+		layout: "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",
+		r:      rand.New(rand.NewSource(time.Now().UnixNano())),
+		mu:     sync.Mutex{},
+	}
+
+	Numeric = &RandomString{
+		layout: "0123456789",
+		r:      rand.New(rand.NewSource(time.Now().UnixNano())),
+		mu:     sync.Mutex{},
+	}
+)
+
+func (c *RandomString) Generate(n int) []byte {
+	c.mu.Lock()
+	var b = make([]byte, n, n)
+	var length = len(c.layout)
+	for i := 0; i < n; i++ {
+		var idx = c.r.Intn(length)
+		b[i] = c.layout[idx]
+	}
+	c.mu.Unlock()
+	return b
+}
+
+func (c *RandomString) Intn(n int) int {
+	c.mu.Lock()
+	x := c.r.Intn(n)
+	c.mu.Unlock()
+	return x
+}
+
+func (c *RandomString) Uint32() uint32 {
+	c.mu.Lock()
+	x := c.r.Uint32()
+	c.mu.Unlock()
+	return x
+}
+
+func (c *RandomString) Uint64() uint64 {
+	c.mu.Lock()
+	x := c.r.Uint64()
+	c.mu.Unlock()
+	return x
+}