MM-57084: Use cache for GetAllProfiles (#26391)

UserStore.GetAllProfiles is a very frequent call. We cache it
when there are no options passed which is the default case.

https://mattermost.atlassian.net/browse/MM-57084

```release-note
NONE
```

server/channels/app/user.go

@@ -263,9 +263,15 @@ func (a *App) createUserOrGuest(c request.CTX, user *model.User, guest bool) (*m
 		}
 	}
 
-	if user.EmailVerified {
-		a.InvalidateCacheForUser(ruser.Id)
+	// We always invalidate the user because we actually need to invalidate
+	// in case the user's EmailVerified is true, but we also always need to invalidate
+	// the GetAllProfiles cache.
+	// To have a proper fix would mean duplicating the invalidation of GetAllProfiles
+	// everywhere else. Therefore, to keep things simple we always invalidate both caches here.
+	// The performance penalty for invalidating the UserById cache is nil because the user was just created.
+	a.InvalidateCacheForUser(ruser.Id)
 
+	if user.EmailVerified {
 		nUser, err := a.ch.srv.userService.GetUser(ruser.Id)
 		if err != nil {
 			var nfErr *store.ErrNotFound

server/channels/store/localcachelayer/layer.go

@@ -112,6 +112,7 @@ type LocalCacheStore struct {
 	postsUsageCache    cache.Cache
 
 	user                   *LocalCacheUserStore
+	allUserCache           cache.Cache
 	userProfileByIdsCache  cache.Cache
 	profilesInChannelCache cache.Cache
 
@@ -315,6 +316,14 @@ func NewLocalCacheLayer(baseStore store.Store, metrics einterfaces.MetricsInterf
 	localCacheStore.termsOfService = LocalCacheTermsOfServiceStore{TermsOfServiceStore: baseStore.TermsOfService(), rootStore: &localCacheStore}
 
 	// Users
+	if localCacheStore.allUserCache, err = cacheProvider.NewCache(&cache.CacheOptions{
+		Size:                   1,
+		Name:                   "AllUserProfiles",
+		DefaultExpiry:          UserProfileByIDSec * time.Second,
+		InvalidateClusterEvent: model.ClusterEventInvalidateCacheForAllProfiles,
+	}); err != nil {
+		return
+	}
 	if localCacheStore.userProfileByIdsCache, err = cacheProvider.NewCache(&cache.CacheOptions{
 		Size:                   UserProfileByIDCacheSize,
 		Name:                   "UserProfileByIds",
@@ -372,6 +381,7 @@ func NewLocalCacheLayer(baseStore store.Store, metrics einterfaces.MetricsInterf
 		cluster.RegisterClusterMessageHandler(model.ClusterEventInvalidateCacheForTermsOfService, localCacheStore.termsOfService.handleClusterInvalidateTermsOfService)
 		cluster.RegisterClusterMessageHandler(model.ClusterEventInvalidateCacheForProfileByIds, localCacheStore.user.handleClusterInvalidateScheme)
 		cluster.RegisterClusterMessageHandler(model.ClusterEventInvalidateCacheForProfileInChannel, localCacheStore.user.handleClusterInvalidateProfilesInChannel)
+		cluster.RegisterClusterMessageHandler(model.ClusterEventInvalidateCacheForAllProfiles, localCacheStore.user.handleClusterInvalidateAllProfiles)
 		cluster.RegisterClusterMessageHandler(model.ClusterEventInvalidateCacheForTeams, localCacheStore.team.handleClusterInvalidateTeam)
 	}
 	return
@@ -497,6 +507,7 @@ func (s *LocalCacheStore) Invalidate() {
 	s.doClearCacheCluster(s.termsOfServiceCache)
 	s.doClearCacheCluster(s.lastPostTimeCache)
 	s.doClearCacheCluster(s.userProfileByIdsCache)
+	s.doClearCacheCluster(s.allUserCache)
 	s.doClearCacheCluster(s.profilesInChannelCache)
 	s.doClearCacheCluster(s.teamAllTeamIdsForUserCache)
 	s.doClearCacheCluster(s.rolePermissionsCache)

server/channels/store/localcachelayer/main_test.go

@@ -157,6 +157,7 @@ func getMockStore(t *testing.T) *mocks.Store {
 	}
 	mockUserStore.On("GetAllProfilesInChannel", mock.Anything, "123", true).Return(fakeProfilesInChannelMap, nil)
 	mockUserStore.On("GetAllProfilesInChannel", mock.Anything, "123", false).Return(fakeProfilesInChannelMap, nil)
+	mockUserStore.On("GetAllProfiles", mock.AnythingOfType("*model.UserGetOptions")).Return(fakeUser, nil)
 
 	mockUserStore.On("Get", mock.Anything, "123").Return(fakeUser[0], nil)
 	users := []*model.User{

server/channels/store/localcachelayer/user_layer.go

@@ -21,6 +21,8 @@ type LocalCacheUserStore struct {
 	userProfileByIdsInvalidations map[string]bool
 }
 
+const allUserKey = "ALL"
+
 func (s *LocalCacheUserStore) handleClusterInvalidateScheme(msg *model.ClusterMessage) {
 	if bytes.Equal(msg.Data, clearCacheMessageData) {
 		s.rootStore.userProfileByIdsCache.Purge()
@@ -40,8 +42,17 @@ func (s *LocalCacheUserStore) handleClusterInvalidateProfilesInChannel(msg *mode
 	}
 }
 
+func (s *LocalCacheUserStore) handleClusterInvalidateAllProfiles(msg *model.ClusterMessage) {
+	if bytes.Equal(msg.Data, clearCacheMessageData) {
+		s.rootStore.allUserCache.Purge()
+	} else {
+		s.rootStore.allUserCache.Remove(string(msg.Data))
+	}
+}
+
 func (s *LocalCacheUserStore) ClearCaches() {
 	s.rootStore.userProfileByIdsCache.Purge()
+	s.rootStore.allUserCache.Purge()
 	s.rootStore.profilesInChannelCache.Purge()
 
 	if s.rootStore.metrics != nil {
@@ -55,6 +66,7 @@ func (s *LocalCacheUserStore) InvalidateProfileCacheForUser(userId string) {
 	s.userProfileByIdsInvalidations[userId] = true
 	s.userProfileByIdsMut.Unlock()
 	s.rootStore.doInvalidateCacheCluster(s.rootStore.userProfileByIdsCache, userId, nil)
+	s.rootStore.doInvalidateCacheCluster(s.rootStore.allUserCache, allUserKey, nil)
 
 	if s.rootStore.metrics != nil {
 		s.rootStore.metrics.IncrementMemCacheInvalidationCounter("Profile By Ids - Remove")
@@ -85,6 +97,30 @@ func (s *LocalCacheUserStore) InvalidateProfilesInChannelCache(channelID string)
 	}
 }
 
+func (s *LocalCacheUserStore) GetAllProfiles(options *model.UserGetOptions) ([]*model.User, error) {
+	if isEmptyOptions(options) &&
+		options.Page == 0 && options.PerPage == 100 { // This is hardcoded to the webapp call.
+		// read from cache
+		var users []*model.User
+		if err := s.rootStore.doStandardReadCache(s.rootStore.allUserCache, allUserKey, &users); err == nil {
+			return users, nil
+		}
+
+		users, err := s.UserStore.GetAllProfiles(options)
+		if err != nil {
+			return nil, err
+		}
+
+		// populate the cache only for those options.
+		s.rootStore.doStandardAddToCache(s.rootStore.allUserCache, allUserKey, users)
+
+		return users, nil
+	}
+
+	// For any other case, simply use the store
+	return s.UserStore.GetAllProfiles(options)
+}
+
 func (s *LocalCacheUserStore) GetAllProfilesInChannel(ctx context.Context, channelId string, allowFromCache bool) (map[string]*model.User, error) {
 	if allowFromCache {
 		var cachedMap map[string]*model.User
@@ -261,3 +297,26 @@ func dedup(elements []string) []string {
 
 	return elements[:j+1]
 }
+
+func isEmptyOptions(options *model.UserGetOptions) bool {
+	// We check to see if any of the options are set or not, and then
+	// use the cache only if none are set, which is the most common case.
+	// options.WithoutTeam, Sort is unused
+	if options.InTeamId == "" &&
+		options.NotInTeamId == "" &&
+		options.InChannelId == "" &&
+		options.NotInChannelId == "" &&
+		options.InGroupId == "" &&
+		options.NotInGroupId == "" &&
+		!options.GroupConstrained &&
+		!options.Inactive &&
+		!options.Active &&
+		options.Role == "" &&
+		len(options.Roles) == 0 &&
+		len(options.ChannelRoles) == 0 &&
+		len(options.TeamRoles) == 0 &&
+		options.ViewRestrictions == nil {
+		return true
+	}
+	return false
+}

server/channels/store/localcachelayer/user_layer_test.go

@@ -118,6 +118,43 @@ func TestUserStoreCache(t *testing.T) {
 	})
 }
 
+func TestUserStoreGetAllProfiles(t *testing.T) {
+	t.Run("first call not cached, second cached and returning same data", func(t *testing.T) {
+		mockStore := getMockStore(t)
+		mockCacheProvider := getMockCacheProvider()
+		cachedStore, err := NewLocalCacheLayer(mockStore, nil, nil, mockCacheProvider)
+		require.NoError(t, err)
+
+		users, err := cachedStore.User().GetAllProfiles(&model.UserGetOptions{Page: 0, PerPage: 100})
+		require.NoError(t, err)
+		mockStore.User().(*mocks.UserStore).AssertNumberOfCalls(t, "GetAllProfiles", 1)
+
+		users2, _ := cachedStore.User().GetAllProfiles(&model.UserGetOptions{Page: 0, PerPage: 100})
+		mockStore.User().(*mocks.UserStore).AssertNumberOfCalls(t, "GetAllProfiles", 1)
+		assert.Equal(t, users, users2)
+
+		_, _ = cachedStore.User().GetAllProfiles(&model.UserGetOptions{Page: 2, PerPage: 1})
+		mockStore.User().(*mocks.UserStore).AssertNumberOfCalls(t, "GetAllProfiles", 2)
+		assert.Equal(t, users, users2)
+	})
+
+	t.Run("different page sizes aren't cached", func(t *testing.T) {
+		mockStore := getMockStore(t)
+		mockCacheProvider := getMockCacheProvider()
+		cachedStore, err := NewLocalCacheLayer(mockStore, nil, nil, mockCacheProvider)
+		require.NoError(t, err)
+
+		_, _ = cachedStore.User().GetAllProfiles(&model.UserGetOptions{Page: 0, PerPage: 100})
+		mockStore.User().(*mocks.UserStore).AssertNumberOfCalls(t, "GetAllProfiles", 1)
+
+		_, _ = cachedStore.User().GetAllProfiles(&model.UserGetOptions{Page: 2, PerPage: 1})
+		mockStore.User().(*mocks.UserStore).AssertNumberOfCalls(t, "GetAllProfiles", 2)
+
+		_, _ = cachedStore.User().GetAllProfiles(&model.UserGetOptions{Page: 1, PerPage: 2})
+		mockStore.User().(*mocks.UserStore).AssertNumberOfCalls(t, "GetAllProfiles", 3)
+	})
+}
+
 func TestUserStoreProfilesInChannelCache(t *testing.T) {
 	fakeChannelId := "123"
 	fakeUserId := "456"

server/public/model/cluster_message.go

@@ -20,6 +20,7 @@ const (
 	ClusterEventInvalidateCacheForRoles                     ClusterEvent = "inv_roles"
 	ClusterEventInvalidateCacheForRolePermissions           ClusterEvent = "inv_role_permissions"
 	ClusterEventInvalidateCacheForProfileByIds              ClusterEvent = "inv_profile_ids"
+	ClusterEventInvalidateCacheForAllProfiles               ClusterEvent = "inv_all_profiles"
 	ClusterEventInvalidateCacheForProfileInChannel          ClusterEvent = "inv_profile_in_channel"
 	ClusterEventInvalidateCacheForSchemes                   ClusterEvent = "inv_schemes"
 	ClusterEventInvalidateCacheForFileInfos                 ClusterEvent = "inv_file_infos"

webapp/channels/src/packages/mattermost-redux/src/constants/general.ts

@@ -8,7 +8,7 @@ export default {
     PAGE_SIZE_MAXIMUM: 200,
     LOGS_PAGE_SIZE_DEFAULT: 10000,
     AUDITS_CHUNK_SIZE: 100,
-    PROFILE_CHUNK_SIZE: 100,
+    PROFILE_CHUNK_SIZE: 100, // WARN: Do not change this without changing the cache key on server side as well. See https://github.com/mattermost/mattermost/pull/26391.
     CHANNELS_CHUNK_SIZE: 50,
     TEAMS_CHUNK_SIZE: 50,
     JOBS_CHUNK_SIZE: 50,