diff --git a/group/memory_group.go b/group/memory_group.go
index a6e809c..dd870c7 100644
--- a/group/memory_group.go
+++ b/group/memory_group.go
@@ -4,13 +4,17 @@ import (
 	"context"
 	"sync"
 	"time"
+
+	"github.com/metagogs/gogs/utils/slicex"
 )
 
 var _ Group = (*MemoryGroup)(nil)
 
 type MemoryGroup struct {
+	mutex       sync.RWMutex
 	name        string
-	uids        sync.Map
+	uids        map[string]struct{}
+	uidsList    []string
 	groupID     int64
 	lastRefresh int64
 }
@@ -19,13 +23,17 @@ func NewMemoryGroup(name string, groupID int64) *MemoryGroup {
 	return &MemoryGroup{
 		name:        name,
 		groupID:     groupID,
+		uids:        make(map[string]struct{}),
 		lastRefresh: time.Now().Unix(),
 	}
 }
 
 func (group *MemoryGroup) AddUser(ctx context.Context, uid string) error {
-	if _, ok := group.uids.Load(uid); !ok {
-		group.uids.Store(uid, uid)
+	group.mutex.Lock()
+	defer group.mutex.Unlock()
+	if _, ok := group.uids[uid]; !ok {
+		group.uids[uid] = struct{}{}
+		group.uidsList = append(group.uidsList, uid)
 		group.lastRefresh = time.Now().Unix()
 		return nil
 	}
@@ -34,8 +42,11 @@ func (group *MemoryGroup) AddUser(ctx context.Context, uid string) error {
 }
 
 func (group *MemoryGroup) RemoveUser(ctx context.Context, uid string) error {
-	if _, ok := group.uids.Load(uid); ok {
-		group.uids.Delete(uid)
+	group.mutex.Lock()
+	defer group.mutex.Unlock()
+	if _, ok := group.uids[uid]; ok {
+		delete(group.uids, uid)
+		group.uidsList = slicex.RemoveSliceItem(group.uidsList, uid)
 		group.lastRefresh = time.Now().Unix()
 		return nil
 	}
@@ -51,31 +62,20 @@ func (group *MemoryGroup) RemoveUsers(ctx context.Context, uids []string) {
 }
 
 func (group *MemoryGroup) RemoveAllUsers(ctx context.Context) {
-	group.uids.Range(func(key, value interface{}) bool {
-		group.uids.Delete(key)
-		group.lastRefresh = time.Now().Unix()
-		return true
-	})
+	group.mutex.Lock()
+	defer group.mutex.Unlock()
+	group.uids = make(map[string]struct{})
+	group.uidsList = nil
 }
 
 func (group *MemoryGroup) GetUsers(ctx context.Context) []string {
-	uids := []string{}
-	group.uids.Range(func(key, value interface{}) bool {
-		uids = append(uids, key.(string))
-		return true
-	})
-
-	return uids
+	group.mutex.RLock()
+	defer group.mutex.RUnlock()
+	return group.uidsList
 }
 
 func (group *MemoryGroup) GetUserCount(ctx context.Context) int {
-	count := 0
-	group.uids.Range(func(key, value interface{}) bool {
-		count++
-		return true
-	})
-
-	return count
+	return len(group.uidsList)
 }
 
 func (group *MemoryGroup) GetLastRefresh(ctx context.Context) int64 {
@@ -83,7 +83,9 @@ func (group *MemoryGroup) GetLastRefresh(ctx context.Context) int64 {
 }
 
 func (group *MemoryGroup) ContainsUser(ctx context.Context, uid string) bool {
-	_, ok := group.uids.Load(uid)
+	group.mutex.RLock()
+	defer group.mutex.RUnlock()
+	_, ok := group.uids[uid]
 	return ok
 }
 
diff --git a/group/memory_group_test.go b/group/memory_group_test.go
index e587b12..ce9fb26 100644
--- a/group/memory_group_test.go
+++ b/group/memory_group_test.go
@@ -1,8 +1,10 @@
 package group
 
 import (
+	"sync"
 	"testing"
 
+	"github.com/metagogs/gogs/utils/randstr"
 	"github.com/stretchr/testify/assert"
 )
 
@@ -64,4 +66,28 @@ func TestMemoryGroup_AddUser(t *testing.T) {
 	exist = memGroup.ContainsUser(nil, "test2")
 	assert.True(t, exist)
 
+	var wg sync.WaitGroup
+	for i := 0; i < 1000; i++ {
+		wg.Add(1)
+		go func() {
+			defer wg.Done()
+			memGroup.AddUser(nil, randstr.RandStr(10))
+			memGroup.AddUser(nil, "test")
+			memGroup.GetUsers(nil)
+			memGroup.GetUserCount(nil)
+			memGroup.GetGroupID(nil)
+			memGroup.GetGroupName(nil)
+			memGroup.ContainsUser(nil, "test")
+			memGroup.ContainsUser(nil, "test2")
+			memGroup.RemoveUser(nil, "test")
+			memGroup.RemoveUsers(nil, []string{"test2"})
+			memGroup.RemoveAllUsers(nil)
+			memGroup.AddUser(nil, randstr.RandStr(10))
+			memGroup.AddUser(nil, "test")
+			memGroup.GetUsers(nil)
+			memGroup.GetUserCount(nil)
+			memGroup.RemoveAllUsers(nil)
+		}()
+	}
+	wg.Wait()
 }
diff --git a/session/pool.go b/session/pool.go
index 8eaa102..64b56b8 100644
--- a/session/pool.go
+++ b/session/pool.go
@@ -61,20 +61,17 @@ func (s *sessionList) GetList(filter *SessionFilter) ([]int64, []int64) {
 	}
 	result := []int64{}
 	for _, v := range s.data {
-		if filter != nil {
-			if len(filter.ConnType) > 0 && v.ConnType != filter.ConnType {
-				continue
-			}
-
-			if len(filter.ConnName) > 0 && v.ConnName != filter.ConnName {
-				continue
-			}
-
-			if len(filter.ConnGroup) > 0 && v.ConnGroup != filter.ConnGroup {
-				continue
-			}
+		if len(filter.ConnType) > 0 && v.ConnType != filter.ConnType {
+			continue
 		}
 
+		if len(filter.ConnName) > 0 && v.ConnName != filter.ConnName {
+			continue
+		}
+
+		if len(filter.ConnGroup) > 0 && v.ConnGroup != filter.ConnGroup {
+			continue
+		}
 		result = append(result, v.SessionID)
 	}