MM-55295: Improve DB performance of some (Take 2) (#25865)

* Revert "Revert "MM-55295: Improve DB performance of some APIs (#25318)" (#25852)"

This reverts commit 077221a940.

* Fix the issue

```release-note
NONE
```

* lint fix

```release-note
NONE
```

server/channels/app/authorization.go

@@ -83,7 +83,6 @@ func (a *App) SessionHasPermissionToChannel(c request.CTX, session model.Session
 	}
 
 	ids, err := a.Srv().Store().Channel().GetAllChannelMembersForUser(session.UserId, true, true)
-
 	var channelRoles []string
 	if err == nil {
 		if roles, ok := ids[channelID]; ok {
@@ -260,17 +259,22 @@ func (a *App) HasPermissionToChannel(c request.CTX, askingUserId string, channel
 		return false
 	}
 
-	channelMember, err := a.GetChannelMember(c, channelID, askingUserId)
+	// We call GetAllChannelMembersForUser instead of just getting
+	// a single member from the DB, because it's cache backed
+	// and this is a very frequent call.
+	ids, err := a.Srv().Store().Channel().GetAllChannelMembersForUser(askingUserId, true, true)
+	var channelRoles []string
 	if err == nil {
-		roles := channelMember.GetRoles()
-		if a.RolesGrantPermission(roles, permission.Id) {
-			return true
+		if roles, ok := ids[channelID]; ok {
+			channelRoles = strings.Fields(roles)
+			if a.RolesGrantPermission(channelRoles, permission.Id) {
+				return true
+			}
 		}
 	}
 
-	var channel *model.Channel
-	channel, err = a.GetChannel(c, channelID)
-	if err == nil {
+	channel, appErr := a.GetChannel(c, channelID)
+	if appErr == nil {
 		return a.HasPermissionToTeam(c, askingUserId, channel.TeamId, permission)
 	}
 

server/channels/app/channel.go

@@ -2063,6 +2063,21 @@ func (s *Server) getChannelMember(c request.CTX, channelID string, userID string
 	return channelMember, nil
 }
 
+func (s *Server) getChannelMemberLastViewedAt(c request.CTX, channelID string, userID string) (int64, *model.AppError) {
+	lastViewedAt, err := s.Store().Channel().GetMemberLastViewedAt(c.Context(), channelID, userID)
+	if err != nil {
+		var nfErr *store.ErrNotFound
+		switch {
+		case errors.As(err, &nfErr):
+			return 0, model.NewAppError("getChannelMemberLastViewedAt", MissingChannelMemberError, nil, "", http.StatusNotFound).Wrap(err)
+		default:
+			return 0, model.NewAppError("getChannelMemberLastViewedAt", "app.channel.get_member.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
+		}
+	}
+
+	return lastViewedAt, nil
+}
+
 func (a *App) GetChannelMembersPage(c request.CTX, channelID string, page, perPage int) (model.ChannelMembers, *model.AppError) {
 	channelMembers, err := a.Srv().Store().Channel().GetMembers(channelID, page*perPage, perPage)
 	if err != nil {

server/channels/app/post.go

@@ -810,9 +810,9 @@ func (a *App) publishWebsocketEventForPermalinkPost(c request.CTX, post *model.P
 		return false, err
 	}
 
-	channelMembers, err := a.GetChannelMembersPage(c, post.ChannelId, 0, 10000000)
-	if err != nil {
-		return false, err
+	userIDs, nErr := a.Srv().Store().Channel().GetAllChannelMemberIdsByChannelId(post.ChannelId)
+	if nErr != nil {
+		return false, model.NewAppError("publishWebsocketEventForPermalinkPost", "app.channel.get_members.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
 	}
 
 	permalinkPreviewedChannel, err := a.GetChannel(c, previewedPost.ChannelId)
@@ -827,19 +827,19 @@ func (a *App) publishWebsocketEventForPermalinkPost(c request.CTX, post *model.P
 	originalEmbeds := post.Metadata.Embeds
 	originalProps := post.GetProps()
 	permalinkPreviewedPost := post.GetPreviewPost()
-	for _, cm := range channelMembers {
+	for _, userID := range userIDs {
 		if permalinkPreviewedPost != nil {
 			post.Metadata.Embeds = originalEmbeds
 			post.SetProps(originalProps)
 		}
 
-		postForUser := a.sanitizePostMetadataForUserAndChannel(c, post, permalinkPreviewedPost, permalinkPreviewedChannel, cm.UserId)
+		postForUser := a.sanitizePostMetadataForUserAndChannel(c, post, permalinkPreviewedPost, permalinkPreviewedChannel, userID)
 
 		// Using DeepCopy here to avoid a race condition
 		// between publishing the event and setting the "post" data value below.
 		messageCopy := message.DeepCopy()
 		broadcastCopy := messageCopy.GetBroadcast()
-		broadcastCopy.UserId = cm.UserId
+		broadcastCopy.UserId = userID
 		messageCopy.SetBroadcast(broadcastCopy)
 
 		postJSON, jsonErr := postForUser.ToJSON()
@@ -1292,15 +1292,15 @@ func (a *App) AddCursorIdsForPostList(originalList *model.PostList, afterPost, b
 	originalList.PrevPostId = prevPostId
 }
 func (a *App) GetPostsForChannelAroundLastUnread(c request.CTX, channelID, userID string, limitBefore, limitAfter int, skipFetchThreads bool, collapsedThreads, collapsedThreadsExtended bool) (*model.PostList, *model.AppError) {
-	var member *model.ChannelMember
+	var lastViewedAt int64
 	var err *model.AppError
-	if member, err = a.GetChannelMember(c, channelID, userID); err != nil {
+	if lastViewedAt, err = a.Srv().getChannelMemberLastViewedAt(c, channelID, userID); err != nil {
 		return nil, err
-	} else if member.LastViewedAt == 0 {
+	} else if lastViewedAt == 0 {
 		return model.NewPostList(), nil
 	}
 
-	lastUnreadPostId, err := a.GetPostIdAfterTime(channelID, member.LastViewedAt, collapsedThreads)
+	lastUnreadPostId, err := a.GetPostIdAfterTime(channelID, lastViewedAt, collapsedThreads)
 	if err != nil {
 		return nil, err
 	} else if lastUnreadPostId == "" {
@@ -1870,9 +1870,9 @@ func (a *App) countThreadMentions(c request.CTX, user *model.User, post *model.P
 // countMentionsFromPost returns the number of posts in the post's channel that mention the user after and including the
 // given post.
 func (a *App) countMentionsFromPost(c request.CTX, user *model.User, post *model.Post) (int, int, int, *model.AppError) {
-	channel, err := a.GetChannel(c, post.ChannelId)
-	if err != nil {
-		return 0, 0, 0, err
+	channel, appErr := a.GetChannel(c, post.ChannelId)
+	if appErr != nil {
+		return 0, 0, 0, appErr
 	}
 
 	if channel.Type == model.ChannelTypeDirect || channel.Type == model.ChannelTypeGroup {
@@ -1893,15 +1893,15 @@ func (a *App) countMentionsFromPost(c request.CTX, user *model.User, post *model
 		return count, countRoot, urgentCount, nil
 	}
 
-	channelMember, err := a.GetChannelMember(c, channel.Id, user.Id)
+	members, err := a.Srv().Store().Channel().GetAllChannelMembersNotifyPropsForChannel(channel.Id, true)
 	if err != nil {
-		return 0, 0, 0, err
+		return 0, 0, 0, model.NewAppError("countMentionsFromPost", "app.channel.count_posts_since.app_error", nil, "", http.StatusInternalServerError).Wrap(err)
 	}
 
 	keywords := MentionKeywords{}
 	keywords.AddUser(
 		user,
-		channelMember.NotifyProps,
+		members[user.Id],
 		&model.Status{Status: model.StatusOnline}, // Assume the user is online since they would've triggered this
 		true, // Assume channel mentions are always allowed for simplicity
 	)
@@ -1911,9 +1911,9 @@ func (a *App) countMentionsFromPost(c request.CTX, user *model.User, post *model
 	// A mapping of thread root IDs to whether or not a post in that thread mentions the user
 	mentionedByThread := make(map[string]bool)
 
-	thread, err := a.GetPostThread(post.Id, model.GetPostsOptions{}, user.Id)
-	if err != nil {
-		return 0, 0, 0, err
+	thread, appErr := a.GetPostThread(post.Id, model.GetPostsOptions{}, user.Id)
+	if appErr != nil {
+		return 0, 0, 0, appErr
 	}
 
 	count := 0

server/channels/store/opentracinglayer/opentracinglayer.go

@@ -965,16 +965,16 @@ func (s *OpenTracingLayerChannelStore) GetAll(teamID string) ([]*model.Channel,
 	return result, err
 }
 
-func (s *OpenTracingLayerChannelStore) GetAllChannelMembersById(id string) ([]string, error) {
+func (s *OpenTracingLayerChannelStore) GetAllChannelMemberIdsByChannelId(id string) ([]string, error) {
 	origCtx := s.Root.Store.Context()
-	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.GetAllChannelMembersById")
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.GetAllChannelMemberIdsByChannelId")
 	s.Root.Store.SetContext(newCtx)
 	defer func() {
 		s.Root.Store.SetContext(origCtx)
 	}()
 
 	defer span.Finish()
-	result, err := s.ChannelStore.GetAllChannelMembersById(id)
+	result, err := s.ChannelStore.GetAllChannelMemberIdsByChannelId(id)
 	if err != nil {
 		span.LogFields(spanlog.Error(err))
 		ext.Error.Set(span, true)
@@ -1572,6 +1572,24 @@ func (s *OpenTracingLayerChannelStore) GetMemberForPost(postID string, userID st
 	return result, err
 }
 
+func (s *OpenTracingLayerChannelStore) GetMemberLastViewedAt(ctx context.Context, channelID string, userID string) (int64, error) {
+	origCtx := s.Root.Store.Context()
+	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.GetMemberLastViewedAt")
+	s.Root.Store.SetContext(newCtx)
+	defer func() {
+		s.Root.Store.SetContext(origCtx)
+	}()
+
+	defer span.Finish()
+	result, err := s.ChannelStore.GetMemberLastViewedAt(ctx, channelID, userID)
+	if err != nil {
+		span.LogFields(spanlog.Error(err))
+		ext.Error.Set(span, true)
+	}
+
+	return result, err
+}
+
 func (s *OpenTracingLayerChannelStore) GetMembers(channelID string, offset int, limit int) (model.ChannelMembers, error) {
 	origCtx := s.Root.Store.Context()
 	span, newCtx := tracing.StartSpanWithParentByContext(s.Root.Store.Context(), "ChannelStore.GetMembers")

server/channels/store/retrylayer/retrylayer.go

@@ -1049,11 +1049,11 @@ func (s *RetryLayerChannelStore) GetAll(teamID string) ([]*model.Channel, error)
 
 }
 
-func (s *RetryLayerChannelStore) GetAllChannelMembersById(id string) ([]string, error) {
+func (s *RetryLayerChannelStore) GetAllChannelMemberIdsByChannelId(id string) ([]string, error) {
 
 	tries := 0
 	for {
-		result, err := s.ChannelStore.GetAllChannelMembersById(id)
+		result, err := s.ChannelStore.GetAllChannelMemberIdsByChannelId(id)
 		if err == nil {
 			return result, nil
 		}
@@ -1748,6 +1748,27 @@ func (s *RetryLayerChannelStore) GetMemberForPost(postID string, userID string,
 
 }
 
+func (s *RetryLayerChannelStore) GetMemberLastViewedAt(ctx context.Context, channelID string, userID string) (int64, error) {
+
+	tries := 0
+	for {
+		result, err := s.ChannelStore.GetMemberLastViewedAt(ctx, channelID, userID)
+		if err == nil {
+			return result, nil
+		}
+		if !isRepeatableError(err) {
+			return result, err
+		}
+		tries++
+		if tries >= 3 {
+			err = errors.Wrap(err, "giving up after 3 consecutive repeatable transaction failures")
+			return result, err
+		}
+		timepkg.Sleep(100 * timepkg.Millisecond)
+	}
+
+}
+
 func (s *RetryLayerChannelStore) GetMembers(channelID string, offset int, limit int) (model.ChannelMembers, error) {
 
 	tries := 0

server/channels/store/searchlayer/channel_layer.go

@@ -40,7 +40,7 @@ func (c *SearchChannelStore) indexChannel(rctx request.CTX, channel *model.Chann
 	var userIDs, teamMemberIDs []string
 	var err error
 	if channel.Type == model.ChannelTypePrivate {
-		userIDs, err = c.GetAllChannelMembersById(channel.Id)
+		userIDs, err = c.GetAllChannelMemberIdsByChannelId(channel.Id)
 		if err != nil {
 			rctx.Logger().Warn("Encountered error while indexing channel", mlog.String("channel_id", channel.Id), mlog.Err(err))
 			return

server/channels/store/sqlstore/channel_store.go

@@ -1126,26 +1126,16 @@ func (s SqlChannelStore) GetChannelsByUser(userId string, includeDeleted bool, l
 	return channels, nil
 }
 
-func (s SqlChannelStore) GetAllChannelMembersById(channelID string) ([]string, error) {
-	sql, args, err := s.channelMembersForTeamWithSchemeSelectQuery.Where(sq.Eq{
-		"ChannelId": channelID,
-	}).ToSql()
-	if err != nil {
-		return nil, errors.Wrap(err, "GetAllChannelMembersById_ToSql")
-	}
-
-	dbMembers := channelMemberWithSchemeRolesList{}
-	err = s.GetReplicaX().Select(&dbMembers, sql, args...)
+func (s SqlChannelStore) GetAllChannelMemberIdsByChannelId(channelID string) ([]string, error) {
+	userIDs := []string{}
+	err := s.GetReplicaX().Select(&userIDs, `SELECT UserId
+		FROM ChannelMembers
+		WHERE ChannelId=?`, channelID)
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to get ChannelMembers with channelID=%s", channelID)
 	}
 
-	res := make([]string, len(dbMembers))
-	for i, member := range dbMembers.ToModel() {
-		res[i] = member.UserId
-	}
-
-	return res, nil
+	return userIDs, nil
 }
 
 func (s SqlChannelStore) GetAllChannels(offset, limit int, opts store.ChannelSearchOpts) (model.ChannelListWithTeamData, error) {
@@ -2070,6 +2060,20 @@ func (s SqlChannelStore) GetMember(ctx context.Context, channelID string, userID
 	return dbMember.ToModel(), nil
 }
 
+func (s SqlChannelStore) GetMemberLastViewedAt(ctx context.Context, channelID string, userID string) (int64, error) {
+	var lastViewedAt int64
+	if err := s.DBXFromContext(ctx).Get(&lastViewedAt, `SELECT COALESCE(LastViewedAt, 0) AS LastViewedAt
+		FROM ChannelMembers
+		WHERE ChannelId=? AND UserId=?`, channelID, userID); err != nil {
+		if err == sql.ErrNoRows {
+			return 0, store.NewErrNotFound("LastViewedAt", fmt.Sprintf("channelId=%s, userId=%s", channelID, userID))
+		}
+		return 0, errors.Wrapf(err, "failed to get lastViewedAt with channelId=%s and userId=%s", channelID, userID)
+	}
+
+	return lastViewedAt, nil
+}
+
 func (s SqlChannelStore) InvalidateAllChannelMembersForUser(userId string) {
 	allChannelMembersForUserCache.Remove(userId)
 	allChannelMembersForUserCache.Remove(userId + "_deleted")

server/channels/store/store.go

@@ -205,7 +205,7 @@ type ChannelStore interface {
 	GetDeleted(team_id string, offset int, limit int, userID string) (model.ChannelList, error)
 	GetChannels(teamID, userID string, opts *model.ChannelSearchOpts) (model.ChannelList, error)
 	GetChannelsByUser(userID string, includeDeleted bool, lastDeleteAt, pageSize int, fromChannelID string) (model.ChannelList, error)
-	GetAllChannelMembersById(id string) ([]string, error)
+	GetAllChannelMemberIdsByChannelId(id string) ([]string, error)
 	GetAllChannels(page, perPage int, opts ChannelSearchOpts) (model.ChannelListWithTeamData, error)
 	GetAllChannelsCount(opts ChannelSearchOpts) (int64, error)
 	GetMoreChannels(teamID string, userID string, offset int, limit int) (model.ChannelList, error)
@@ -227,6 +227,7 @@ type ChannelStore interface {
 	UpdateMemberNotifyProps(channelID, userID string, props map[string]string) (*model.ChannelMember, error)
 	GetMembers(channelID string, offset, limit int) (model.ChannelMembers, error)
 	GetMember(ctx context.Context, channelID string, userID string) (*model.ChannelMember, error)
+	GetMemberLastViewedAt(ctx context.Context, channelID string, userID string) (int64, error)
 	GetChannelMembersTimezones(channelID string) ([]model.StringMap, error)
 	GetAllChannelMembersForUser(userID string, allowFromCache bool, includeDeleted bool) (map[string]string, error)
 	GetChannelsMemberCount(channelIDs []string) (map[string]int64, error)

server/channels/store/storetest/channel_store.go

@@ -110,6 +110,7 @@ func TestChannelStore(t *testing.T, rctx request.CTX, ss store.Store, s SqlStore
 	t.Run("IncrementMentionCount", func(t *testing.T) { testChannelStoreIncrementMentionCount(t, rctx, ss) })
 	t.Run("UpdateChannelMember", func(t *testing.T) { testUpdateChannelMember(t, rctx, ss) })
 	t.Run("GetMember", func(t *testing.T) { testGetMember(t, rctx, ss) })
+	t.Run("GetMemberLastViewedAt", func(t *testing.T) { testGetMemberLastViewedAt(t, rctx, ss) })
 	t.Run("GetMemberForPost", func(t *testing.T) { testChannelStoreGetMemberForPost(t, rctx, ss) })
 	t.Run("GetMemberCount", func(t *testing.T) { testGetMemberCount(t, rctx, ss) })
 	t.Run("GetMemberCountsByGroup", func(t *testing.T) { testGetMemberCountsByGroup(t, rctx, ss) })
@@ -246,6 +247,10 @@ func testChannelStoreSaveDirectChannel(t *testing.T, rctx request.CTX, ss store.
 	require.NoError(t, nErr)
 	require.Len(t, members, 2, "should have saved 2 members")
 
+	userIDs, nErr := ss.Channel().GetAllChannelMemberIdsByChannelId(o1.Id)
+	require.NoError(t, nErr)
+	require.ElementsMatch(t, []string{u1.Id, u2.Id}, userIDs)
+
 	_, nErr = ss.Channel().SaveDirectChannel(rctx, &o1, &m1, &m2)
 	require.Error(t, nErr, "shouldn't be a able to update from save")
 
@@ -282,6 +287,10 @@ func testChannelStoreSaveDirectChannel(t *testing.T, rctx request.CTX, ss store.
 	require.NoError(t, nErr)
 	require.Len(t, members, 1, "should have saved just 1 member")
 
+	userIDs, nErr = ss.Channel().GetAllChannelMemberIdsByChannelId(o1.Id)
+	require.NoError(t, nErr)
+	require.ElementsMatch(t, []string{u1.Id}, userIDs)
+
 	// Manually truncate Channels table until testlib can handle cleanups
 	s.GetMasterX().Exec("TRUNCATE Channels")
 }
@@ -4892,6 +4901,62 @@ func testGetMember(t *testing.T, rctx request.CTX, ss store.Store) {
 	ss.Channel().InvalidateCacheForChannelMembersNotifyProps(c2.Id)
 }
 
+func testGetMemberLastViewedAt(t *testing.T, rctx request.CTX, ss store.Store) {
+	userId := model.NewId()
+
+	c1 := &model.Channel{
+		TeamId:      model.NewId(),
+		DisplayName: model.NewId(),
+		Name:        model.NewId(),
+		Type:        model.ChannelTypeOpen,
+	}
+	_, nErr := ss.Channel().Save(c1, -1)
+	require.NoError(t, nErr)
+
+	c2 := &model.Channel{
+		TeamId:      c1.TeamId,
+		DisplayName: model.NewId(),
+		Name:        model.NewId(),
+		Type:        model.ChannelTypeOpen,
+	}
+	_, nErr = ss.Channel().Save(c2, -1)
+	require.NoError(t, nErr)
+
+	m1 := &model.ChannelMember{
+		ChannelId:    c1.Id,
+		UserId:       userId,
+		NotifyProps:  model.GetDefaultChannelNotifyProps(),
+		LastViewedAt: int64(100),
+	}
+	_, err := ss.Channel().SaveMember(m1)
+	require.NoError(t, err)
+
+	m2 := &model.ChannelMember{
+		ChannelId:    c2.Id,
+		UserId:       userId,
+		NotifyProps:  model.GetDefaultChannelNotifyProps(),
+		LastViewedAt: int64(200),
+	}
+	_, err = ss.Channel().SaveMember(m2)
+	require.NoError(t, err)
+
+	_, err = ss.Channel().GetMemberLastViewedAt(context.Background(), model.NewId(), userId)
+	require.Error(t, err, "should've failed to get member for non-existent channel")
+
+	_, err = ss.Channel().GetMemberLastViewedAt(context.Background(), c1.Id, model.NewId())
+	require.Error(t, err, "should've failed to get member for non-existent user")
+
+	lvAt, err := ss.Channel().GetMemberLastViewedAt(context.Background(), c1.Id, userId)
+	require.NoError(t, err, "shouldn't have errored when getting member", err)
+	require.Equal(t, m1.LastViewedAt, lvAt, "should've gotten LastViewedAt of channel 1")
+
+	lvAt, err = ss.Channel().GetMemberLastViewedAt(context.Background(), c2.Id, userId)
+	require.NoError(t, err, "shouldn't have errored when getting member", err)
+	require.Equal(t, m2.LastViewedAt, lvAt, "should've gotten gotten LastViewedAt of channel 2")
+
+	ss.Channel().InvalidateCacheForChannelMembersNotifyProps(c2.Id)
+}
+
 func testChannelStoreGetMemberForPost(t *testing.T, rctx request.CTX, ss store.Store) {
 	ch := &model.Channel{
 		TeamId:      model.NewId(),
@@ -7477,6 +7542,10 @@ func testChannelStoreRemoveAllDeactivatedMembers(t *testing.T, rctx request.CTX,
 	assert.NoError(t, err)
 	assert.Len(t, d1, 3)
 
+	userIDs, nErr := ss.Channel().GetAllChannelMemberIdsByChannelId(c1.Id)
+	require.NoError(t, nErr)
+	require.ElementsMatch(t, []string{u1.Id, u2.Id, u3.Id}, userIDs)
+
 	// Deactivate users 1 & 2.
 	u1.DeleteAt = model.GetMillis()
 	u2.DeleteAt = model.GetMillis()
@@ -7494,6 +7563,10 @@ func testChannelStoreRemoveAllDeactivatedMembers(t *testing.T, rctx request.CTX,
 	assert.Len(t, d2, 1)
 	assert.Equal(t, u3.Id, d2[0].UserId)
 
+	userIDs, nErr = ss.Channel().GetAllChannelMemberIdsByChannelId(c1.Id)
+	require.NoError(t, nErr)
+	require.ElementsMatch(t, []string{u3.Id}, userIDs)
+
 	// Manually truncate Channels table until testlib can handle cleanups
 	s.GetMasterX().Exec("TRUNCATE Channels")
 }

server/channels/store/storetest/mocks/ChannelStore.go

@@ -432,8 +432,8 @@ func (_m *ChannelStore) GetAll(teamID string) ([]*model.Channel, error) {
 	return r0, r1
 }
 
-// GetAllChannelMembersById provides a mock function with given fields: id
-func (_m *ChannelStore) GetAllChannelMembersById(id string) ([]string, error) {
+// GetAllChannelMemberIdsByChannelId provides a mock function with given fields: id
+func (_m *ChannelStore) GetAllChannelMemberIdsByChannelId(id string) ([]string, error) {
 	ret := _m.Called(id)
 
 	var r0 []string
@@ -1314,6 +1314,30 @@ func (_m *ChannelStore) GetMemberForPost(postID string, userID string, includeAr
 	return r0, r1
 }
 
+// GetMemberLastViewedAt provides a mock function with given fields: ctx, channelID, userID
+func (_m *ChannelStore) GetMemberLastViewedAt(ctx context.Context, channelID string, userID string) (int64, error) {
+	ret := _m.Called(ctx, channelID, userID)
+
+	var r0 int64
+	var r1 error
+	if rf, ok := ret.Get(0).(func(context.Context, string, string) (int64, error)); ok {
+		return rf(ctx, channelID, userID)
+	}
+	if rf, ok := ret.Get(0).(func(context.Context, string, string) int64); ok {
+		r0 = rf(ctx, channelID, userID)
+	} else {
+		r0 = ret.Get(0).(int64)
+	}
+
+	if rf, ok := ret.Get(1).(func(context.Context, string, string) error); ok {
+		r1 = rf(ctx, channelID, userID)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
 // GetMembers provides a mock function with given fields: channelID, offset, limit
 func (_m *ChannelStore) GetMembers(channelID string, offset int, limit int) (model.ChannelMembers, error) {
 	ret := _m.Called(channelID, offset, limit)

server/channels/store/timerlayer/timerlayer.go

@@ -917,10 +917,10 @@ func (s *TimerLayerChannelStore) GetAll(teamID string) ([]*model.Channel, error)
 	return result, err
 }
 
-func (s *TimerLayerChannelStore) GetAllChannelMembersById(id string) ([]string, error) {
+func (s *TimerLayerChannelStore) GetAllChannelMemberIdsByChannelId(id string) ([]string, error) {
 	start := time.Now()
 
-	result, err := s.ChannelStore.GetAllChannelMembersById(id)
+	result, err := s.ChannelStore.GetAllChannelMemberIdsByChannelId(id)
 
 	elapsed := float64(time.Since(start)) / float64(time.Second)
 	if s.Root.Metrics != nil {
@@ -928,7 +928,7 @@ func (s *TimerLayerChannelStore) GetAllChannelMembersById(id string) ([]string,
 		if err == nil {
 			success = "true"
 		}
-		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.GetAllChannelMembersById", success, elapsed)
+		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.GetAllChannelMemberIdsByChannelId", success, elapsed)
 	}
 	return result, err
 }
@@ -1461,6 +1461,22 @@ func (s *TimerLayerChannelStore) GetMemberForPost(postID string, userID string,
 	return result, err
 }
 
+func (s *TimerLayerChannelStore) GetMemberLastViewedAt(ctx context.Context, channelID string, userID string) (int64, error) {
+	start := time.Now()
+
+	result, err := s.ChannelStore.GetMemberLastViewedAt(ctx, channelID, userID)
+
+	elapsed := float64(time.Since(start)) / float64(time.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if err == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("ChannelStore.GetMemberLastViewedAt", success, elapsed)
+	}
+	return result, err
+}
+
 func (s *TimerLayerChannelStore) GetMembers(channelID string, offset int, limit int) (model.ChannelMembers, error) {
 	start := time.Now()
 

server/platform/services/searchengine/bleveengine/indexer/indexing_job.go

@@ -526,7 +526,7 @@ func (worker *BleveIndexerWorker) BulkIndexChannels(logger mlog.LoggerIFace, cha
 			var userIDs []string
 			var err error
 			if channel.Type == model.ChannelTypePrivate {
-				userIDs, err = worker.jobServer.Store.Channel().GetAllChannelMembersById(channel.Id)
+				userIDs, err = worker.jobServer.Store.Channel().GetAllChannelMemberIdsByChannelId(channel.Id)
 				if err != nil {
 					return nil, model.NewAppError("BleveIndexerWorker.BulkIndexChannels", "bleveengine.indexer.do_job.bulk_index_channels.batch_error", nil, "", http.StatusInternalServerError).Wrap(err)
 				}