MM-21552: Adding SaveMultiple to posts (#13766)

* Adding SaveMultiple to posts

* Improving tests

* fixing i18n

* Fixing tests

* Improving testing on top of Save and SaveMultiple

* Fixing shadow variables

* Addressing some PR comments

* More clear update post test

* Addressing some PR comments

* Addressing some PR comments and simplifying the code

* Improting replies in bulk too

* Fixing reply count and processing last imported replies

* Adding OverwriteMultiple to posts aggregating everything in the same transaction

* Adding 2 pending tests to implement

* Adding tests for overwrite multiple posts

* Adding tests for TeamStore.GetByNames method

* Fixing shadow variables

* Addressing PR comments

* Extracting i18n strings

* Fixing tests

* Fixing tests

* Adding more test cases

* Using a variable instead of a fake timestamp

app/import.go

@@ -16,7 +16,10 @@ import (
 	"github.com/mattermost/mattermost-server/v5/model"
 )
 
-const maxScanTokenSize = 16 * 1024 * 1024 // Need to set a higher limit than default because some customers cross the limit. See MM-22314
+const (
+	importMultiplePostsThreshold = 1000
+	maxScanTokenSize             = 16 * 1024 * 1024 // Need to set a higher limit than default because some customers cross the limit. See MM-22314
+)
 
 func stopOnError(err LineImportWorkerError) bool {
 	if err.Error.Id == "api.file.upload_file.large_image.app_error" {
@@ -27,11 +30,41 @@ func stopOnError(err LineImportWorkerError) bool {
 }
 
 func (a *App) bulkImportWorker(dryRun bool, wg *sync.WaitGroup, lines <-chan LineImportWorkerData, errors chan<- LineImportWorkerError) {
+	posts := []*PostImportData{}
+	directPosts := []*DirectPostImportData{}
 	for line := range lines {
-		if err := a.importLine(line.LineImportData, dryRun); err != nil {
-			errors <- LineImportWorkerError{err, line.LineNumber}
+		switch {
+		case line.LineImportData.Type == "post":
+			posts = append(posts, line.Post)
+			if line.Post == nil {
+				errors <- LineImportWorkerError{model.NewAppError("BulkImport", "app.import.import_line.null_post.error", nil, "", http.StatusBadRequest), line.LineNumber}
+			}
+			if len(posts) >= importMultiplePostsThreshold {
+				a.importMultiplePosts(posts, dryRun)
+				posts = []*PostImportData{}
+			}
+		case line.LineImportData.Type == "direct_post":
+			directPosts = append(directPosts, line.DirectPost)
+			if line.DirectPost == nil {
+				errors <- LineImportWorkerError{model.NewAppError("BulkImport", "app.import.import_line.null_direct_post.error", nil, "", http.StatusBadRequest), line.LineNumber}
+			}
+			if len(directPosts) >= importMultiplePostsThreshold {
+				a.importMultipleDirectPosts(directPosts, dryRun)
+				directPosts = []*DirectPostImportData{}
+			}
+		default:
+			if err := a.importLine(line.LineImportData, dryRun); err != nil {
+				errors <- LineImportWorkerError{err, line.LineNumber}
+			}
 		}
 	}
+
+	if len(posts) > 0 {
+		a.importMultiplePosts(posts, dryRun)
+	}
+	if len(directPosts) > 0 {
+		a.importMultipleDirectPosts(directPosts, dryRun)
+	}
 	wg.Done()
 }
 
@@ -159,21 +192,11 @@ func (a *App) importLine(line LineImportData, dryRun bool) *model.AppError {
 			return model.NewAppError("BulkImport", "app.import.import_line.null_user.error", nil, "", http.StatusBadRequest)
 		}
 		return a.importUser(line.User, dryRun)
-	case line.Type == "post":
-		if line.Post == nil {
-			return model.NewAppError("BulkImport", "app.import.import_line.null_post.error", nil, "", http.StatusBadRequest)
-		}
-		return a.importPost(line.Post, dryRun)
 	case line.Type == "direct_channel":
 		if line.DirectChannel == nil {
 			return model.NewAppError("BulkImport", "app.import.import_line.null_direct_channel.error", nil, "", http.StatusBadRequest)
 		}
 		return a.importDirectChannel(line.DirectChannel, dryRun)
-	case line.Type == "direct_post":
-		if line.DirectPost == nil {
-			return model.NewAppError("BulkImport", "app.import.import_line.null_direct_post.error", nil, "", http.StatusBadRequest)
-		}
-		return a.importDirectPost(line.DirectPost, dryRun)
 	case line.Type == "emoji":
 		if line.Emoji == nil {
 			return model.NewAppError("BulkImport", "app.import.import_line.null_emoji.error", nil, "", http.StatusBadRequest)

app/import_functions.go

@@ -851,67 +851,87 @@ func (a *App) importReaction(data *ReactionImportData, post *model.Post, dryRun
 	return nil
 }
 
-func (a *App) importReply(data *ReplyImportData, post *model.Post, teamId string, dryRun bool) *model.AppError {
+func (a *App) importReplies(data []ReplyImportData, post *model.Post, teamId string, dryRun bool) *model.AppError {
 	var err *model.AppError
-	if err = validateReplyImportData(data, post.CreateAt, a.MaxPostSize()); err != nil {
-		return err
-	}
-
-	var user *model.User
-	user, err = a.Srv().Store.User().GetByUsername(*data.User)
-	if err != nil {
-		return model.NewAppError("BulkImport", "app.import.import_post.user_not_found.error", map[string]interface{}{"Username": data.User}, err.Error(), http.StatusBadRequest)
-	}
-
-	// Check if this post already exists.
-	replies, err := a.Srv().Store.Post().GetPostsCreatedAt(post.ChannelId, *data.CreateAt)
-	if err != nil {
-		return err
-	}
-
-	var reply *model.Post
-	for _, r := range replies {
-		if r.Message == *data.Message && r.RootId == post.Id {
-			reply = r
-			break
-		}
-	}
-
-	if reply == nil {
-		reply = &model.Post{}
-	}
-	reply.UserId = user.Id
-	reply.ChannelId = post.ChannelId
-	reply.ParentId = post.Id
-	reply.RootId = post.Id
-	reply.Message = *data.Message
-	reply.CreateAt = *data.CreateAt
-
-	fileIds, err := a.uploadAttachments(data.Attachments, reply, teamId, dryRun)
-	if err != nil {
-		return err
-	}
-	for _, fileID := range reply.FileIds {
-		if _, ok := fileIds[fileID]; !ok {
-			a.Srv().Store.FileInfo().PermanentDelete(fileID)
-		}
-	}
-	reply.FileIds = make([]string, 0)
-	for fileID := range fileIds {
-		reply.FileIds = append(reply.FileIds, fileID)
-	}
-
-	if reply.Id == "" {
-		if _, err := a.Srv().Store.Post().Save(reply); err != nil {
+	usernames := []string{}
+	for _, replyData := range data {
+		if err = validateReplyImportData(&replyData, post.CreateAt, a.MaxPostSize()); err != nil {
 			return err
 		}
-	} else {
-		if _, err := a.Srv().Store.Post().Overwrite(reply); err != nil {
+		usernames = append(usernames, *replyData.User)
+	}
+
+	users, err := a.getUsersByUsernames(usernames)
+	if err != nil {
+		return err
+	}
+
+	postsWithData := []postAndData{}
+	postsForCreateList := []*model.Post{}
+	postsForOverwriteList := []*model.Post{}
+
+	for _, replyData := range data {
+		user := users[*replyData.User]
+
+		// Check if this post already exists.
+		replies, err := a.Srv().Store.Post().GetPostsCreatedAt(post.ChannelId, *replyData.CreateAt)
+		if err != nil {
+			return err
+		}
+
+		var reply *model.Post
+		for _, r := range replies {
+			if r.Message == *replyData.Message && r.RootId == post.Id {
+				reply = r
+				break
+			}
+		}
+
+		if reply == nil {
+			reply = &model.Post{}
+		}
+		reply.UserId = user.Id
+		reply.ChannelId = post.ChannelId
+		reply.ParentId = post.Id
+		reply.RootId = post.Id
+		reply.Message = *replyData.Message
+		reply.CreateAt = *replyData.CreateAt
+
+		fileIds, err := a.uploadAttachments(replyData.Attachments, reply, teamId, dryRun)
+		if err != nil {
+			return err
+		}
+		for _, fileID := range reply.FileIds {
+			if _, ok := fileIds[fileID]; !ok {
+				a.Srv().Store.FileInfo().PermanentDelete(fileID)
+			}
+		}
+		reply.FileIds = make([]string, 0)
+		for fileID := range fileIds {
+			reply.FileIds = append(reply.FileIds, fileID)
+		}
+
+		if len(reply.Id) == 0 {
+			postsForCreateList = append(postsForCreateList, reply)
+		} else {
+			postsForOverwriteList = append(postsForOverwriteList, reply)
+		}
+		postsWithData = append(postsWithData, postAndData{post: reply, replyData: &replyData})
+	}
+
+	if len(postsForCreateList) > 0 {
+		if _, err := a.Srv().Store.Post().SaveMultiple(postsForCreateList); err != nil {
 			return err
 		}
 	}
 
-	a.updateFileInfoWithPostId(reply)
+	if _, err := a.Srv().Store.Post().OverwriteMultiple(postsForOverwriteList); err != nil {
+		return err
+	}
+
+	for _, postWithData := range postsWithData {
+		a.updateFileInfoWithPostId(postWithData.post)
+	}
 
 	return nil
 }
@@ -961,9 +981,70 @@ func (a *App) importAttachment(data *AttachmentImportData, post *model.Post, tea
 	return fileInfo, nil
 }
 
-func (a *App) importPost(data *PostImportData, dryRun bool) *model.AppError {
-	if err := validatePostImportData(data, a.MaxPostSize()); err != nil {
-		return err
+type postAndData struct {
+	post           *model.Post
+	postData       *PostImportData
+	directPostData *DirectPostImportData
+	replyData      *ReplyImportData
+	team           *model.Team
+}
+
+func (a *App) getUsersByUsernames(usernames []string) (map[string]*model.User, *model.AppError) {
+	uniqueUsernames := utils.RemoveDuplicatesFromStringArray(usernames)
+	allUsers, err := a.Srv().Store.User().GetProfilesByUsernames(uniqueUsernames, nil)
+	if err != nil {
+		return nil, model.NewAppError("BulkImport", "app.import.get_users_by_username.some_users_not_found.error", nil, err.Error(), http.StatusBadRequest)
+	}
+
+	if len(allUsers) != len(uniqueUsernames) {
+		return nil, model.NewAppError("BulkImport", "app.import.get_users_by_username.some_users_not_found.error", nil, "", http.StatusBadRequest)
+	}
+
+	users := make(map[string]*model.User)
+	for _, user := range allUsers {
+		users[user.Username] = user
+	}
+	return users, nil
+}
+
+func (a *App) getTeamsByNames(names []string) (map[string]*model.Team, *model.AppError) {
+	allTeams, err := a.Srv().Store.Team().GetByNames(names)
+	if err != nil {
+		return nil, model.NewAppError("BulkImport", "app.import.get_teams_by_names.some_teams_not_found.error", nil, err.Error(), http.StatusBadRequest)
+	}
+
+	teams := make(map[string]*model.Team)
+	for _, team := range allTeams {
+		teams[team.Name] = team
+	}
+	return teams, nil
+}
+
+func (a *App) getChannelsForPosts(teams map[string]*model.Team, data []*PostImportData) (map[string]*model.Channel, *model.AppError) {
+	channels := make(map[string]*model.Channel)
+	for _, postData := range data {
+		team := teams[*postData.Team]
+		if channel, ok := channels[*postData.Channel]; !ok || channel == nil {
+			var err *model.AppError
+			channel, err = a.Srv().Store.Channel().GetByName(team.Id, *postData.Channel, true)
+			if err != nil {
+				return nil, model.NewAppError("BulkImport", "app.import.import_post.channel_not_found.error", map[string]interface{}{"ChannelName": *postData.Channel}, err.Error(), http.StatusBadRequest)
+			}
+			channels[*postData.Channel] = channel
+		}
+	}
+	return channels, nil
+}
+
+func (a *App) importMultiplePosts(data []*PostImportData, dryRun bool) *model.AppError {
+	if len(data) == 0 {
+		return nil
+	}
+
+	for _, postData := range data {
+		if err := validatePostImportData(postData, a.MaxPostSize()); err != nil {
+			return err
+		}
 	}
 
 	// If this is a Dry Run, do not continue any further.
@@ -971,113 +1052,148 @@ func (a *App) importPost(data *PostImportData, dryRun bool) *model.AppError {
 		return nil
 	}
 
-	team, err := a.Srv().Store.Team().GetByName(*data.Team)
-	if err != nil {
-		return model.NewAppError("BulkImport", "app.import.import_post.team_not_found.error", map[string]interface{}{"TeamName": *data.Team}, err.Error(), http.StatusBadRequest)
+	usernames := []string{}
+	teamNames := []string{}
+	for _, postData := range data {
+		usernames = append(usernames, *postData.User)
+		if postData.FlaggedBy != nil {
+			usernames = append(usernames, *postData.FlaggedBy...)
+		}
+		teamNames = append(teamNames, *postData.Team)
 	}
 
-	channel, err := a.Srv().Store.Channel().GetByName(team.Id, *data.Channel, false)
-	if err != nil {
-		return model.NewAppError("BulkImport", "app.import.import_post.channel_not_found.error", map[string]interface{}{"ChannelName": *data.Channel}, err.Error(), http.StatusBadRequest)
-	}
-
-	var user *model.User
-	user, err = a.Srv().Store.User().GetByUsername(*data.User)
-	if err != nil {
-		return model.NewAppError("BulkImport", "app.import.import_post.user_not_found.error", map[string]interface{}{"Username": *data.User}, err.Error(), http.StatusBadRequest)
-	}
-
-	// Check if this post already exists.
-	posts, err := a.Srv().Store.Post().GetPostsCreatedAt(channel.Id, *data.CreateAt)
+	users, err := a.getUsersByUsernames(usernames)
 	if err != nil {
 		return err
 	}
 
-	var post *model.Post
-	for _, p := range posts {
-		if p.Message == *data.Message {
-			post = p
-			break
-		}
-	}
-
-	if post == nil {
-		post = &model.Post{}
-	}
-
-	post.ChannelId = channel.Id
-	post.Message = *data.Message
-	post.UserId = user.Id
-	post.CreateAt = *data.CreateAt
-
-	post.Hashtags, _ = model.ParseHashtags(post.Message)
-
-	fileIds, err := a.uploadAttachments(data.Attachments, post, team.Id, dryRun)
+	teams, err := a.getTeamsByNames(teamNames)
 	if err != nil {
 		return err
 	}
-	for _, fileID := range post.FileIds {
-		if _, ok := fileIds[fileID]; !ok {
-			a.Srv().Store.FileInfo().PermanentDelete(fileID)
-		}
-	}
-	post.FileIds = make([]string, 0)
-	for fileID := range fileIds {
-		post.FileIds = append(post.FileIds, fileID)
-	}
 
-	if post.Id == "" {
-		if _, err = a.Srv().Store.Post().Save(post); err != nil {
+	channels, err := a.getChannelsForPosts(teams, data)
+	if err != nil {
+		return err
+	}
+	postsWithData := []postAndData{}
+	postsForCreateList := []*model.Post{}
+	postsForOverwriteList := []*model.Post{}
+
+	for _, postData := range data {
+		team := teams[*postData.Team]
+		channel := channels[*postData.Channel]
+		user := users[*postData.User]
+
+		// Check if this post already exists.
+		posts, err := a.Srv().Store.Post().GetPostsCreatedAt(channel.Id, *postData.CreateAt)
+		if err != nil {
 			return err
 		}
-	} else {
-		if _, err = a.Srv().Store.Post().Overwrite(post); err != nil {
+
+		var post *model.Post
+		for _, p := range posts {
+			if p.Message == *postData.Message {
+				post = p
+				break
+			}
+		}
+
+		if post == nil {
+			post = &model.Post{}
+		}
+
+		post.ChannelId = channel.Id
+		post.Message = *postData.Message
+		post.UserId = user.Id
+		post.CreateAt = *postData.CreateAt
+		post.Hashtags, _ = model.ParseHashtags(post.Message)
+
+		fileIds, err := a.uploadAttachments(postData.Attachments, post, team.Id, dryRun)
+		if err != nil {
+			return err
+		}
+		for _, fileID := range post.FileIds {
+			if _, ok := fileIds[fileID]; !ok {
+				a.Srv().Store.FileInfo().PermanentDelete(fileID)
+			}
+		}
+		post.FileIds = make([]string, 0)
+		for fileID := range fileIds {
+			post.FileIds = append(post.FileIds, fileID)
+		}
+
+		if len(post.Id) == 0 {
+			postsForCreateList = append(postsForCreateList, post)
+		} else {
+			postsForOverwriteList = append(postsForOverwriteList, post)
+		}
+		postsWithData = append(postsWithData, postAndData{post: post, postData: postData, team: team})
+	}
+
+	if len(postsForCreateList) > 0 {
+		if _, err := a.Srv().Store.Post().SaveMultiple(postsForCreateList); err != nil {
 			return err
 		}
 	}
 
-	if data.FlaggedBy != nil {
-		var preferences model.Preferences
+	if _, err := a.Srv().Store.Post().OverwriteMultiple(postsForOverwriteList); err != nil {
+		return err
+	}
 
-		for _, username := range *data.FlaggedBy {
-			var user *model.User
-			user, err = a.Srv().Store.User().GetByUsername(username)
-			if err != nil {
-				return model.NewAppError("BulkImport", "app.import.import_post.user_not_found.error", map[string]interface{}{"Username": username}, err.Error(), http.StatusBadRequest)
+	var lastPostWithData *postAndData
+	repliesBulk := []ReplyImportData{}
+	for _, postWithData := range postsWithData {
+		if postWithData.postData.FlaggedBy != nil {
+			var preferences model.Preferences
+
+			for _, username := range *postWithData.postData.FlaggedBy {
+				user := users[username]
+
+				preferences = append(preferences, model.Preference{
+					UserId:   user.Id,
+					Category: model.PREFERENCE_CATEGORY_FLAGGED_POST,
+					Name:     postWithData.post.Id,
+					Value:    "true",
+				})
 			}
 
-			preferences = append(preferences, model.Preference{
-				UserId:   user.Id,
-				Category: model.PREFERENCE_CATEGORY_FLAGGED_POST,
-				Name:     post.Id,
-				Value:    "true",
-			})
+			if len(preferences) > 0 {
+				if err := a.Srv().Store.Preference().Save(&preferences); err != nil {
+					return model.NewAppError("BulkImport", "app.import.import_post.save_preferences.error", nil, err.Error(), http.StatusInternalServerError)
+				}
+			}
 		}
 
-		if len(preferences) > 0 {
-			if err := a.Srv().Store.Preference().Save(&preferences); err != nil {
-				return model.NewAppError("BulkImport", "app.import.import_post.save_preferences.error", nil, err.Error(), http.StatusInternalServerError)
+		if postWithData.postData.Reactions != nil {
+			for _, reaction := range *postWithData.postData.Reactions {
+				if err := a.importReaction(&reaction, postWithData.post, dryRun); err != nil {
+					return err
+				}
 			}
 		}
+
+		if postWithData.postData.Replies != nil {
+			repliesBulk = append(repliesBulk, *postWithData.postData.Replies...)
+			if len(repliesBulk) >= importMultiplePostsThreshold {
+				err := a.importReplies(repliesBulk, postWithData.post, postWithData.team.Id, dryRun)
+				if err != nil {
+					return err
+				}
+				repliesBulk = []ReplyImportData{}
+			}
+		}
+		a.updateFileInfoWithPostId(postWithData.post)
+		lastPostWithData = &postWithData
+	}
+
+	if len(repliesBulk) >= 0 && lastPostWithData != nil {
+		err := a.importReplies(repliesBulk, lastPostWithData.post, lastPostWithData.team.Id, dryRun)
+		if err != nil {
+			return err
+		}
 	}
 
-	if data.Reactions != nil {
-		for _, reaction := range *data.Reactions {
-			if err := a.importReaction(&reaction, post, dryRun); err != nil {
-				return err
-			}
-		}
-	}
-
-	if data.Replies != nil {
-		for _, reply := range *data.Replies {
-			if err := a.importReply(&reply, post, team.Id, dryRun); err != nil {
-				return err
-			}
-		}
-	}
-
-	a.updateFileInfoWithPostId(post)
 	return nil
 }
 
@@ -1116,15 +1232,12 @@ func (a *App) importDirectChannel(data *DirectChannelImportData, dryRun bool) *m
 	}
 
 	var userIds []string
-	userMap := make(map[string]string)
-	for _, username := range *data.Members {
-		var user *model.User
-		user, err = a.Srv().Store.User().GetByUsername(username)
-		if err != nil {
-			return model.NewAppError("BulkImport", "app.import.import_direct_channel.member_not_found.error", nil, err.Error(), http.StatusBadRequest)
-		}
-		userIds = append(userIds, user.Id)
-		userMap[username] = user.Id
+	userMap, err := a.getUsersByUsernames(*data.Members)
+	if err != nil {
+		return err
+	}
+	for _, user := range *data.Members {
+		userIds = append(userIds, userMap[user].Id)
 	}
 
 	var channel *model.Channel
@@ -1157,7 +1270,7 @@ func (a *App) importDirectChannel(data *DirectChannelImportData, dryRun bool) *m
 	if data.FavoritedBy != nil {
 		for _, favoriter := range *data.FavoritedBy {
 			preferences = append(preferences, model.Preference{
-				UserId:   userMap[favoriter],
+				UserId:   userMap[favoriter].Id,
 				Category: model.PREFERENCE_CATEGORY_FAVORITE_CHANNEL,
 				Name:     channel.Id,
 				Value:    "true",
@@ -1180,10 +1293,15 @@ func (a *App) importDirectChannel(data *DirectChannelImportData, dryRun bool) *m
 	return nil
 }
 
-func (a *App) importDirectPost(data *DirectPostImportData, dryRun bool) *model.AppError {
-	var err *model.AppError
-	if err = validateDirectPostImportData(data, a.MaxPostSize()); err != nil {
-		return err
+func (a *App) importMultipleDirectPosts(data []*DirectPostImportData, dryRun bool) *model.AppError {
+	if len(data) == 0 {
+		return nil
+	}
+
+	for _, postData := range data {
+		if err := validateDirectPostImportData(postData, a.MaxPostSize()); err != nil {
+			return err
+		}
 	}
 
 	// If this is a Dry Run, do not continue any further.
@@ -1191,129 +1309,143 @@ func (a *App) importDirectPost(data *DirectPostImportData, dryRun bool) *model.A
 		return nil
 	}
 
-	var userIds []string
-	for _, username := range *data.ChannelMembers {
-		var user *model.User
-		user, err = a.Srv().Store.User().GetByUsername(username)
+	usernames := []string{}
+	for _, postData := range data {
+		usernames = append(usernames, *postData.User)
+		if postData.FlaggedBy != nil {
+			usernames = append(usernames, *postData.FlaggedBy...)
+		}
+		usernames = append(usernames, *postData.ChannelMembers...)
+	}
+
+	users, err := a.getUsersByUsernames(usernames)
+	if err != nil {
+		return err
+	}
+
+	postsWithData := []postAndData{}
+	postsForCreateList := []*model.Post{}
+	postsForOverwriteList := []*model.Post{}
+
+	for _, postData := range data {
+		var userIds []string
+		var err *model.AppError
+		for _, username := range *postData.ChannelMembers {
+			user := users[username]
+			userIds = append(userIds, user.Id)
+		}
+
+		var channel *model.Channel
+		var ch *model.Channel
+		if len(userIds) == 2 {
+			ch, err = a.GetOrCreateDirectChannel(userIds[0], userIds[1])
+			if err != nil && err.Id != store.CHANNEL_EXISTS_ERROR {
+				return model.NewAppError("BulkImport", "app.import.import_direct_post.create_direct_channel.error", nil, err.Error(), http.StatusBadRequest)
+			}
+			channel = ch
+		} else {
+			ch, err = a.createGroupChannel(userIds, userIds[0])
+			if err != nil && err.Id != store.CHANNEL_EXISTS_ERROR {
+				return model.NewAppError("BulkImport", "app.import.import_direct_post.create_group_channel.error", nil, err.Error(), http.StatusBadRequest)
+			}
+			channel = ch
+		}
+
+		user := users[*postData.User]
+
+		// Check if this post already exists.
+		posts, err := a.Srv().Store.Post().GetPostsCreatedAt(channel.Id, *postData.CreateAt)
 		if err != nil {
-			return model.NewAppError("BulkImport", "app.import.import_direct_post.channel_member_not_found.error", nil, err.Error(), http.StatusBadRequest)
-		}
-		userIds = append(userIds, user.Id)
-	}
-
-	var channel *model.Channel
-	var ch *model.Channel
-	if len(userIds) == 2 {
-		ch, err = a.createDirectChannel(userIds[0], userIds[1])
-		if err != nil && err.Id != store.CHANNEL_EXISTS_ERROR {
-			return model.NewAppError("BulkImport", "app.import.import_direct_post.create_direct_channel.error", nil, err.Error(), http.StatusBadRequest)
-		}
-		channel = ch
-	} else {
-		ch, err = a.createGroupChannel(userIds, userIds[0])
-		if err != nil && err.Id != store.CHANNEL_EXISTS_ERROR {
-			return model.NewAppError("BulkImport", "app.import.import_direct_post.create_group_channel.error", nil, err.Error(), http.StatusBadRequest)
-		}
-		channel = ch
-	}
-
-	var user *model.User
-	user, err = a.Srv().Store.User().GetByUsername(*data.User)
-	if err != nil {
-		return model.NewAppError("BulkImport", "app.import.import_direct_post.user_not_found.error", map[string]interface{}{"Username": *data.User}, "", http.StatusBadRequest)
-	}
-
-	// Check if this post already exists.
-	posts, err := a.Srv().Store.Post().GetPostsCreatedAt(channel.Id, *data.CreateAt)
-	if err != nil {
-		return err
-	}
-
-	var post *model.Post
-	for _, p := range posts {
-		if p.Message == *data.Message {
-			post = p
-			break
-		}
-	}
-
-	if post == nil {
-		post = &model.Post{}
-	}
-
-	post.ChannelId = channel.Id
-	post.Message = *data.Message
-	post.UserId = user.Id
-	post.CreateAt = *data.CreateAt
-
-	post.Hashtags, _ = model.ParseHashtags(post.Message)
-
-	fileIds, err := a.uploadAttachments(data.Attachments, post, "noteam", dryRun)
-	if err != nil {
-		return err
-	}
-	for _, fileID := range post.FileIds {
-		if _, ok := fileIds[fileID]; !ok {
-			a.Srv().Store.FileInfo().PermanentDelete(fileID)
-		}
-	}
-	post.FileIds = make([]string, 0)
-	for fileID := range fileIds {
-		post.FileIds = append(post.FileIds, fileID)
-	}
-
-	if post.Id == "" {
-		if _, err = a.Srv().Store.Post().Save(post); err != nil {
 			return err
 		}
-	} else {
-		if _, err = a.Srv().Store.Post().Overwrite(post); err != nil {
+
+		var post *model.Post
+		for _, p := range posts {
+			if p.Message == *postData.Message {
+				post = p
+				break
+			}
+		}
+
+		if post == nil {
+			post = &model.Post{}
+		}
+
+		post.ChannelId = channel.Id
+		post.Message = *postData.Message
+		post.UserId = user.Id
+		post.CreateAt = *postData.CreateAt
+		post.Hashtags, _ = model.ParseHashtags(post.Message)
+
+		fileIds, err := a.uploadAttachments(postData.Attachments, post, "noteam", dryRun)
+		if err != nil {
+			return err
+		}
+		for _, fileID := range post.FileIds {
+			if _, ok := fileIds[fileID]; !ok {
+				a.Srv().Store.FileInfo().PermanentDelete(fileID)
+			}
+		}
+		post.FileIds = make([]string, 0)
+		for fileID := range fileIds {
+			post.FileIds = append(post.FileIds, fileID)
+		}
+
+		if len(post.Id) == 0 {
+			postsForCreateList = append(postsForCreateList, post)
+		} else {
+			postsForOverwriteList = append(postsForOverwriteList, post)
+		}
+		postsWithData = append(postsWithData, postAndData{post: post, directPostData: postData})
+	}
+
+	if len(postsForCreateList) > 0 {
+		if _, err := a.Srv().Store.Post().SaveMultiple(postsForCreateList); err != nil {
 			return err
 		}
 	}
-
-	if data.FlaggedBy != nil {
-		var preferences model.Preferences
-
-		for _, username := range *data.FlaggedBy {
-			var user *model.User
-			user, err = a.Srv().Store.User().GetByUsername(username)
-			if err != nil {
-				return model.NewAppError("BulkImport", "app.import.import_direct_post.user_not_found.error", map[string]interface{}{"Username": username}, "", http.StatusBadRequest)
-			}
-
-			preferences = append(preferences, model.Preference{
-				UserId:   user.Id,
-				Category: model.PREFERENCE_CATEGORY_FLAGGED_POST,
-				Name:     post.Id,
-				Value:    "true",
-			})
-		}
-
-		if len(preferences) > 0 {
-			if err := a.Srv().Store.Preference().Save(&preferences); err != nil {
-				return model.NewAppError("BulkImport", "app.import.import_direct_post.save_preferences.error", nil, err.Error(), http.StatusInternalServerError)
-			}
-		}
+	if _, err := a.Srv().Store.Post().OverwriteMultiple(postsForOverwriteList); err != nil {
+		return err
 	}
 
-	if data.Reactions != nil {
-		for _, reaction := range *data.Reactions {
-			if err := a.importReaction(&reaction, post, dryRun); err != nil {
+	for _, postWithData := range postsWithData {
+		if postWithData.directPostData.FlaggedBy != nil {
+			var preferences model.Preferences
+
+			for _, username := range *postWithData.directPostData.FlaggedBy {
+				user := users[username]
+
+				preferences = append(preferences, model.Preference{
+					UserId:   user.Id,
+					Category: model.PREFERENCE_CATEGORY_FLAGGED_POST,
+					Name:     postWithData.post.Id,
+					Value:    "true",
+				})
+			}
+
+			if len(preferences) > 0 {
+				if err := a.Srv().Store.Preference().Save(&preferences); err != nil {
+					return model.NewAppError("BulkImport", "app.import.import_post.save_preferences.error", nil, err.Error(), http.StatusInternalServerError)
+				}
+			}
+		}
+
+		if postWithData.directPostData.Reactions != nil {
+			for _, reaction := range *postWithData.directPostData.Reactions {
+				if err := a.importReaction(&reaction, postWithData.post, dryRun); err != nil {
+					return err
+				}
+			}
+		}
+
+		if postWithData.directPostData.Replies != nil {
+			if err := a.importReplies(*postWithData.directPostData.Replies, postWithData.post, "noteam", dryRun); err != nil {
 				return err
 			}
 		}
-	}
 
-	if data.Replies != nil {
-		for _, reply := range *data.Replies {
-			if err := a.importReply(&reply, post, "noteam", dryRun); err != nil {
-				return err
-			}
-		}
+		a.updateFileInfoWithPostId(postWithData.post)
 	}
-
-	a.updateFileInfoWithPostId(post)
 	return nil
 }
 

app/import_test.go

@@ -239,12 +239,12 @@ func GetAttachments(userId string, th *TestHelper, t *testing.T) []*model.FileIn
 
 func AssertFileIdsInPost(files []*model.FileInfo, th *TestHelper, t *testing.T) {
 	postId := files[0].PostId
-	assert.NotNil(t, postId)
+	require.NotNil(t, postId)
 
 	posts, err := th.App.Srv().Store.Post().GetPostsByIds([]string{postId})
 	require.Nil(t, err)
 
-	assert.Equal(t, len(posts), 1)
+	require.Len(t, posts, 1)
 	for _, file := range files {
 		assert.Contains(t, posts[0].FileIds, file.Id)
 	}

cmd/mattermost/commands/sampledata.go

@@ -325,6 +325,11 @@ func sampleDataCmdF(command *cobra.Command, args []string) error {
 		user2 := allUsers[rand.Intn(len(allUsers))]
 		channelLine := createDirectChannel([]string{user1, user2})
 		encoder.Encode(channelLine)
+	}
+
+	for i := 0; i < directChannels; i++ {
+		user1 := allUsers[rand.Intn(len(allUsers))]
+		user2 := allUsers[rand.Intn(len(allUsers))]
 
 		dates := sortedRandomDates(postsPerDirectChannel)
 		for j := 0; j < postsPerDirectChannel; j++ {
@@ -344,6 +349,17 @@ func sampleDataCmdF(command *cobra.Command, args []string) error {
 		}
 		channelLine := createDirectChannel(users)
 		encoder.Encode(channelLine)
+	}
+
+	for i := 0; i < groupChannels; i++ {
+		users := []string{}
+		totalUsers := 3 + rand.Intn(3)
+		for len(users) < totalUsers {
+			user := allUsers[rand.Intn(len(allUsers))]
+			if !sliceIncludes(users, user) {
+				users = append(users, user)
+			}
+		}
 
 		dates := sortedRandomDates(postsPerGroupChannel)
 		for j := 0; j < postsPerGroupChannel; j++ {

i18n/en.json

@@ -2958,6 +2958,14 @@
     "id": "app.import.emoji.bad_file.error",
     "translation": "Error reading import emoji image file. Emoji with name: \"{{.EmojiName}}\""
   },
+  {
+    "id": "app.import.get_teams_by_names.some_teams_not_found.error",
+    "translation": "Some teams not found"
+  },
+  {
+    "id": "app.import.get_users_by_username.some_users_not_found.error",
+    "translation": "Some users not found"
+  },
   {
     "id": "app.import.import_channel.scheme_deleted.error",
     "translation": "Unable to set a channel to use a deleted scheme."
@@ -2978,18 +2986,10 @@
     "id": "app.import.import_direct_channel.create_group_channel.error",
     "translation": "Failed to create group channel"
   },
-  {
-    "id": "app.import.import_direct_channel.member_not_found.error",
-    "translation": "Could not find channel member when importing direct channel"
-  },
   {
     "id": "app.import.import_direct_channel.update_header_failed.error",
     "translation": "Failed to update direct channel header"
   },
-  {
-    "id": "app.import.import_direct_post.channel_member_not_found.error",
-    "translation": "Could not find channel member when importing direct channel post"
-  },
   {
     "id": "app.import.import_direct_post.create_direct_channel.error",
     "translation": "Failed to get direct channel"
@@ -2998,14 +2998,6 @@
     "id": "app.import.import_direct_post.create_group_channel.error",
     "translation": "Failed to get group channel"
   },
-  {
-    "id": "app.import.import_direct_post.save_preferences.error",
-    "translation": "Error importing direct post. Failed to save preferences."
-  },
-  {
-    "id": "app.import.import_direct_post.user_not_found.error",
-    "translation": "Post user does not exist"
-  },
   {
     "id": "app.import.import_line.null_channel.error",
     "translation": "Import data line has type \"channel\" but the channel object is null."
@@ -3050,10 +3042,6 @@
     "id": "app.import.import_post.save_preferences.error",
     "translation": "Error importing post. Failed to save preferences."
   },
-  {
-    "id": "app.import.import_post.team_not_found.error",
-    "translation": "Error importing post. Team with name \"{{.TeamName}}\" could not be found."
-  },
   {
     "id": "app.import.import_post.user_not_found.error",
     "translation": "Error importing post. User with username \"{{.Username}}\" could not be found."
@@ -6982,6 +6970,14 @@
     "id": "store.sql_team.get_by_name.missing.app_error",
     "translation": "Unable to find the existing team."
   },
+  {
+    "id": "store.sql_team.get_by_names.app_error",
+    "translation": "Unable to get the teams by names"
+  },
+  {
+    "id": "store.sql_team.get_by_names.missing.app_error",
+    "translation": "Unable to find some of the requested teams"
+  },
   {
     "id": "store.sql_team.get_by_scheme.app_error",
     "translation": "Unable to get the channels for the provided scheme."

store/sqlstore/post_store.go

@@ -30,6 +30,33 @@ type SqlPostStore struct {
 func (s *SqlPostStore) ClearCaches() {
 }
 
+func postSliceColumns() []string {
+	return []string{"Id", "CreateAt", "UpdateAt", "EditAt", "DeleteAt", "IsPinned", "UserId", "ChannelId", "RootId", "ParentId", "OriginalId", "Message", "Type", "Props", "Hashtags", "Filenames", "FileIds", "HasReactions"}
+}
+
+func postToSlice(post *model.Post) []interface{} {
+	return []interface{}{
+		post.Id,
+		post.CreateAt,
+		post.UpdateAt,
+		post.EditAt,
+		post.DeleteAt,
+		post.IsPinned,
+		post.UserId,
+		post.ChannelId,
+		post.RootId,
+		post.ParentId,
+		post.OriginalId,
+		post.Message,
+		post.Type,
+		model.StringInterfaceToJson(post.Props),
+		post.Hashtags,
+		model.ArrayToJson(post.Filenames),
+		model.ArrayToJson(post.FileIds),
+		post.HasReactions,
+	}
+}
+
 func newSqlPostStore(sqlStore SqlStore, metrics einterfaces.MetricsInterface) store.PostStore {
 	s := &SqlPostStore{
 		SqlStore:          sqlStore,
@@ -72,48 +99,97 @@ func (s *SqlPostStore) createIndexesIfNotExists() {
 	s.CreateFullTextIndexIfNotExists("idx_posts_hashtags_txt", "Posts", "Hashtags")
 }
 
-func (s *SqlPostStore) Save(post *model.Post) (*model.Post, *model.AppError) {
-	if len(post.Id) > 0 {
-		return nil, model.NewAppError("SqlPostStore.Save", "store.sql_post.save.existing.app_error", nil, "id="+post.Id, http.StatusBadRequest)
-	}
-
-	maxPostSize := s.GetMaxPostSize()
-
-	post.PreSave()
-	if err := post.IsValid(maxPostSize); err != nil {
-		return nil, err
-	}
-
-	if err := s.GetMaster().Insert(post); err != nil {
-		return nil, model.NewAppError("SqlPostStore.Save", "store.sql_post.save.app_error", nil, "id="+post.Id+", "+err.Error(), http.StatusInternalServerError)
-	}
-
-	time := post.UpdateAt
-
-	if !post.IsJoinLeaveMessage() {
-		if _, err := s.GetMaster().Exec("UPDATE Channels SET LastPostAt = GREATEST(:LastPostAt, LastPostAt), TotalMsgCount = TotalMsgCount + 1 WHERE Id = :ChannelId", map[string]interface{}{"LastPostAt": time, "ChannelId": post.ChannelId}); err != nil {
-			mlog.Error("Error updating Channel LastPostAt.", mlog.Err(err))
+func (s *SqlPostStore) SaveMultiple(posts []*model.Post) ([]*model.Post, *model.AppError) {
+	channelNewPosts := make(map[string]int)
+	maxDateNewPosts := make(map[string]int64)
+	rootIds := make(map[string]int)
+	maxDateRootIds := make(map[string]int64)
+	for _, post := range posts {
+		if len(post.Id) > 0 {
+			return nil, model.NewAppError("SqlPostStore.Save", "store.sql_post.save.existing.app_error", nil, "id="+post.Id, http.StatusBadRequest)
 		}
-	} else {
-		// don't update TotalMsgCount for unimportant messages so that the channel isn't marked as unread
-		if _, err := s.GetMaster().Exec("UPDATE Channels SET LastPostAt = :LastPostAt WHERE Id = :ChannelId AND LastPostAt < :LastPostAt", map[string]interface{}{"LastPostAt": time, "ChannelId": post.ChannelId}); err != nil {
+		post.PreSave()
+		maxPostSize := s.GetMaxPostSize()
+		if err := post.IsValid(maxPostSize); err != nil {
+			return nil, err
+		}
+
+		currentChannelCount, ok := channelNewPosts[post.ChannelId]
+		if !ok {
+			if post.IsJoinLeaveMessage() {
+				channelNewPosts[post.ChannelId] = 0
+			} else {
+				channelNewPosts[post.ChannelId] = 1
+			}
+			maxDateNewPosts[post.ChannelId] = post.CreateAt
+		} else {
+			if !post.IsJoinLeaveMessage() {
+				channelNewPosts[post.ChannelId] = currentChannelCount + 1
+			}
+			if post.CreateAt > maxDateNewPosts[post.ChannelId] {
+				maxDateNewPosts[post.ChannelId] = post.CreateAt
+			}
+		}
+
+		if len(post.RootId) == 0 {
+			continue
+		}
+
+		currentRootCount, ok := rootIds[post.RootId]
+		if !ok {
+			rootIds[post.RootId] = 1
+			maxDateRootIds[post.RootId] = post.CreateAt
+		} else {
+			rootIds[post.RootId] = currentRootCount + 1
+			if post.CreateAt > maxDateRootIds[post.RootId] {
+				maxDateRootIds[post.RootId] = post.CreateAt
+			}
+		}
+	}
+
+	query := s.getQueryBuilder().Insert("Posts").Columns(postSliceColumns()...)
+	for _, post := range posts {
+		query = query.Values(postToSlice(post)...)
+	}
+	sql, args, err := query.ToSql()
+	if err != nil {
+		return nil, model.NewAppError("SqlPostStore.Save", "store.sql_post.save.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	if _, err := s.GetMaster().Exec(sql, args...); err != nil {
+		return nil, model.NewAppError("SqlPostStore.Save", "store.sql_post.save.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	for channelId, count := range channelNewPosts {
+		if _, err := s.GetMaster().Exec("UPDATE Channels SET LastPostAt = GREATEST(:LastPostAt, LastPostAt), TotalMsgCount = TotalMsgCount + :Count WHERE Id = :ChannelId", map[string]interface{}{"LastPostAt": maxDateNewPosts[channelId], "ChannelId": channelId, "Count": count}); err != nil {
 			mlog.Error("Error updating Channel LastPostAt.", mlog.Err(err))
 		}
 	}
 
-	if len(post.RootId) > 0 {
-		if _, err := s.GetMaster().Exec("UPDATE Posts SET UpdateAt = :UpdateAt WHERE Id = :RootId", map[string]interface{}{"UpdateAt": time, "RootId": post.RootId}); err != nil {
+	for rootId := range rootIds {
+		if _, err := s.GetMaster().Exec("UPDATE Posts SET UpdateAt = :UpdateAt WHERE Id = :RootId", map[string]interface{}{"UpdateAt": maxDateRootIds[rootId], "RootId": rootId}); err != nil {
 			mlog.Error("Error updating Post UpdateAt.", mlog.Err(err))
 		}
-	} else {
-		if count, err := s.GetMaster().SelectInt("SELECT COUNT(*) FROM Posts WHERE RootId = :Id", map[string]interface{}{"Id": post.Id}); err != nil {
-			mlog.Error("Error fetching post's thread.", mlog.Err(err))
-		} else {
-			post.ReplyCount = count
+	}
+
+	for _, post := range posts {
+		if len(post.RootId) == 0 {
+			count, ok := rootIds[post.Id]
+			if ok {
+				post.ReplyCount += int64(count)
+			}
 		}
 	}
 
-	return post, nil
+	return posts, nil
+}
+
+func (s *SqlPostStore) Save(post *model.Post) (*model.Post, *model.AppError) {
+	posts, err := s.SaveMultiple([]*model.Post{post})
+	if err != nil {
+		return nil, err
+	}
+	return posts[0], nil
 }
 
 func (s *SqlPostStore) Update(newPost *model.Post, oldPost *model.Post) (*model.Post, *model.AppError) {
@@ -149,19 +225,45 @@ func (s *SqlPostStore) Update(newPost *model.Post, oldPost *model.Post) (*model.
 	return newPost, nil
 }
 
-func (s *SqlPostStore) Overwrite(post *model.Post) (*model.Post, *model.AppError) {
-	post.UpdateAt = model.GetMillis()
-
+func (s *SqlPostStore) OverwriteMultiple(posts []*model.Post) ([]*model.Post, *model.AppError) {
+	updateAt := model.GetMillis()
 	maxPostSize := s.GetMaxPostSize()
-	if appErr := post.IsValid(maxPostSize); appErr != nil {
-		return nil, appErr
+	for _, post := range posts {
+		post.UpdateAt = updateAt
+		if appErr := post.IsValid(maxPostSize); appErr != nil {
+			return nil, appErr
+		}
 	}
 
-	if _, err := s.GetMaster().Update(post); err != nil {
-		return nil, model.NewAppError("SqlPostStore.Overwrite", "store.sql_post.overwrite.app_error", nil, "id="+post.Id+", "+err.Error(), http.StatusInternalServerError)
+	tx, err := s.GetMaster().Begin()
+	if err != nil {
+		return nil, model.NewAppError("SqlPostStore.Overwrite", "store.sql_post.overwrite.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	for _, post := range posts {
+		if _, err = tx.Update(post); err != nil {
+			txErr := tx.Rollback()
+			if txErr != nil {
+				return nil, model.NewAppError("SqlPostStore.Overwrite", "store.sql_post.overwrite.app_error", nil, txErr.Error(), http.StatusInternalServerError)
+			}
+
+			return nil, model.NewAppError("SqlPostStore.Overwrite", "store.sql_post.overwrite.app_error", nil, "id="+post.Id+", "+err.Error(), http.StatusInternalServerError)
+		}
+	}
+	err = tx.Commit()
+	if err != nil {
+		return nil, model.NewAppError("SqlPostStore.Overwrite", "store.sql_post.overwrite.app_error", nil, err.Error(), http.StatusInternalServerError)
 	}
 
-	return post, nil
+	return posts, nil
+}
+
+func (s *SqlPostStore) Overwrite(post *model.Post) (*model.Post, *model.AppError) {
+	posts, err := s.OverwriteMultiple([]*model.Post{post})
+	if err != nil {
+		return nil, err
+	}
+
+	return posts[0], nil
 }
 
 func (s *SqlPostStore) GetFlaggedPosts(userId string, offset int, limit int) (*model.PostList, *model.AppError) {

store/sqlstore/team_store.go

@@ -13,6 +13,7 @@ import (
 	"github.com/mattermost/gorp"
 	"github.com/mattermost/mattermost-server/v5/model"
 	"github.com/mattermost/mattermost-server/v5/store"
+	"github.com/mattermost/mattermost-server/v5/utils"
 )
 
 const (
@@ -287,6 +288,33 @@ func (s SqlTeamStore) GetByName(name string) (*model.Team, *model.AppError) {
 	return &team, nil
 }
 
+func (s SqlTeamStore) GetByNames(names []string) ([]*model.Team, *model.AppError) {
+	uniqueNames := utils.RemoveDuplicatesFromStringArray(names)
+
+	query := s.getQueryBuilder().
+		Select("*").
+		From("Teams").
+		Where(sq.Eq{"Name": uniqueNames})
+
+	queryString, args, err := query.ToSql()
+	if err != nil {
+		return nil, model.NewAppError("SqlTeamStore.GetByNames", "store.sql_team.get_by_names.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+
+	teams := []*model.Team{}
+	_, err = s.GetReplica().Select(&teams, queryString, args...)
+	if err != nil {
+		if err == sql.ErrNoRows {
+			return nil, model.NewAppError("SqlTeamStore.GetByNames", "store.sql_team.get_by_names.missing.app_error", nil, err.Error(), http.StatusNotFound)
+		}
+		return nil, model.NewAppError("SqlTeamStore.GetByNames", "store.sql_team.get_by_names.app_error", nil, err.Error(), http.StatusInternalServerError)
+	}
+	if len(teams) != len(uniqueNames) {
+		return nil, model.NewAppError("SqlTeamStore.GetByNames", "store.sql_team.get_by_names.missing.app_error", nil, "", http.StatusNotFound)
+	}
+	return teams, nil
+}
+
 func (s SqlTeamStore) SearchAll(term string) ([]*model.Team, *model.AppError) {
 	var teams []*model.Team
 

store/store.go

@@ -67,6 +67,7 @@ type TeamStore interface {
 	Update(team *model.Team) (*model.Team, *model.AppError)
 	Get(id string) (*model.Team, *model.AppError)
 	GetByName(name string) (*model.Team, *model.AppError)
+	GetByNames(name []string) ([]*model.Team, *model.AppError)
 	SearchAll(term string) ([]*model.Team, *model.AppError)
 	SearchAllPaged(term string, page int, perPage int) ([]*model.Team, int64, *model.AppError)
 	SearchOpen(term string) ([]*model.Team, *model.AppError)
@@ -218,6 +219,7 @@ type ChannelMemberHistoryStore interface {
 }
 
 type PostStore interface {
+	SaveMultiple(posts []*model.Post) ([]*model.Post, *model.AppError)
 	Save(post *model.Post) (*model.Post, *model.AppError)
 	Update(newPost *model.Post, oldPost *model.Post) (*model.Post, *model.AppError)
 	Get(id string, skipFetchThreads bool) (*model.PostList, *model.AppError)
@@ -245,6 +247,7 @@ type PostStore interface {
 	InvalidateLastPostTimeCache(channelId string)
 	GetPostsCreatedAt(channelId string, time int64) ([]*model.Post, *model.AppError)
 	Overwrite(post *model.Post) (*model.Post, *model.AppError)
+	OverwriteMultiple(posts []*model.Post) ([]*model.Post, *model.AppError)
 	GetPostsByIds(postIds []string) ([]*model.Post, *model.AppError)
 	GetPostsBatchForIndexing(startTime int64, endTime int64, limit int) ([]*model.PostForIndexing, *model.AppError)
 	PermanentDeleteBatch(endTime int64, limit int64) (int64, *model.AppError)

store/storetest/mocks/PostStore.go

@@ -637,6 +637,31 @@ func (_m *PostStore) Overwrite(post *model.Post) (*model.Post, *model.AppError)
 	return r0, r1
 }
 
+// OverwriteMultiple provides a mock function with given fields: posts
+func (_m *PostStore) OverwriteMultiple(posts []*model.Post) ([]*model.Post, *model.AppError) {
+	ret := _m.Called(posts)
+
+	var r0 []*model.Post
+	if rf, ok := ret.Get(0).(func([]*model.Post) []*model.Post); ok {
+		r0 = rf(posts)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).([]*model.Post)
+		}
+	}
+
+	var r1 *model.AppError
+	if rf, ok := ret.Get(1).(func([]*model.Post) *model.AppError); ok {
+		r1 = rf(posts)
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(*model.AppError)
+		}
+	}
+
+	return r0, r1
+}
+
 // PermanentDeleteBatch provides a mock function with given fields: endTime, limit
 func (_m *PostStore) PermanentDeleteBatch(endTime int64, limit int64) (int64, *model.AppError) {
 	ret := _m.Called(endTime, limit)
@@ -717,6 +742,31 @@ func (_m *PostStore) Save(post *model.Post) (*model.Post, *model.AppError) {
 	return r0, r1
 }
 
+// SaveMultiple provides a mock function with given fields: posts
+func (_m *PostStore) SaveMultiple(posts []*model.Post) ([]*model.Post, *model.AppError) {
+	ret := _m.Called(posts)
+
+	var r0 []*model.Post
+	if rf, ok := ret.Get(0).(func([]*model.Post) []*model.Post); ok {
+		r0 = rf(posts)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).([]*model.Post)
+		}
+	}
+
+	var r1 *model.AppError
+	if rf, ok := ret.Get(1).(func([]*model.Post) *model.AppError); ok {
+		r1 = rf(posts)
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(*model.AppError)
+		}
+	}
+
+	return r0, r1
+}
+
 // Search provides a mock function with given fields: teamId, userId, params
 func (_m *PostStore) Search(teamId string, userId string, params *model.SearchParams) (*model.PostList, *model.AppError) {
 	ret := _m.Called(teamId, userId, params)

store/storetest/mocks/TeamStore.go

@@ -425,6 +425,31 @@ func (_m *TeamStore) GetByName(name string) (*model.Team, *model.AppError) {
 	return r0, r1
 }
 
+// GetByNames provides a mock function with given fields: name
+func (_m *TeamStore) GetByNames(name []string) ([]*model.Team, *model.AppError) {
+	ret := _m.Called(name)
+
+	var r0 []*model.Team
+	if rf, ok := ret.Get(0).(func([]string) []*model.Team); ok {
+		r0 = rf(name)
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).([]*model.Team)
+		}
+	}
+
+	var r1 *model.AppError
+	if rf, ok := ret.Get(1).(func([]string) *model.AppError); ok {
+		r1 = rf(name)
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(*model.AppError)
+		}
+	}
+
+	return r0, r1
+}
+
 // GetChannelUnreadsForAllTeams provides a mock function with given fields: excludeTeamId, userId
 func (_m *TeamStore) GetChannelUnreadsForAllTeams(excludeTeamId string, userId string) ([]*model.ChannelUnread, *model.AppError) {
 	ret := _m.Called(excludeTeamId, userId)

store/storetest/post_store.go

@@ -18,6 +18,7 @@ import (
 )
 
 func TestPostStore(t *testing.T, ss store.Store, s SqlSupplier) {
+	t.Run("SaveMultiple", func(t *testing.T) { testPostStoreSaveMultiple(t, ss) })
 	t.Run("Save", func(t *testing.T) { testPostStoreSave(t, ss) })
 	t.Run("SaveAndUpdateChannelMsgCounts", func(t *testing.T) { testPostStoreSaveChannelMsgCounts(t, ss) })
 	t.Run("Get", func(t *testing.T) { testPostStoreGet(t, ss) })
@@ -41,6 +42,7 @@ func TestPostStore(t *testing.T, ss store.Store, s SqlSupplier) {
 	t.Run("GetFlaggedPostsForChannel", func(t *testing.T) { testPostStoreGetFlaggedPostsForChannel(t, ss) })
 	t.Run("GetPostsCreatedAt", func(t *testing.T) { testPostStoreGetPostsCreatedAt(t, ss) })
 	t.Run("Overwrite", func(t *testing.T) { testPostStoreOverwrite(t, ss) })
+	t.Run("OverwriteMultiple", func(t *testing.T) { testPostStoreOverwriteMultiple(t, ss) })
 	t.Run("GetPostsByIds", func(t *testing.T) { testPostStoreGetPostsByIds(t, ss) })
 	t.Run("GetPostsBatchForIndexing", func(t *testing.T) { testPostStoreGetPostsBatchForIndexing(t, ss) })
 	t.Run("PermanentDeleteBatch", func(t *testing.T) { testPostStorePermanentDeleteBatch(t, ss) })
@@ -54,16 +56,223 @@ func TestPostStore(t *testing.T, ss store.Store, s SqlSupplier) {
 }
 
 func testPostStoreSave(t *testing.T, ss store.Store) {
-	o1 := model.Post{}
-	o1.ChannelId = model.NewId()
-	o1.UserId = model.NewId()
-	o1.Message = "zz" + model.NewId() + "b"
+	t.Run("Save post", func(t *testing.T) {
+		o1 := model.Post{}
+		o1.ChannelId = model.NewId()
+		o1.UserId = model.NewId()
+		o1.Message = "zz" + model.NewId() + "b"
 
-	_, err := ss.Post().Save(&o1)
-	require.Nil(t, err, "couldn't save item")
+		_, err := ss.Post().Save(&o1)
+		require.Nil(t, err, "couldn't save item")
+	})
 
-	_, err = ss.Post().Save(&o1)
-	require.NotNil(t, err, "shouldn't be able to update from save")
+	t.Run("Try to save existing post", func(t *testing.T) {
+		o1 := model.Post{}
+		o1.ChannelId = model.NewId()
+		o1.UserId = model.NewId()
+		o1.Message = "zz" + model.NewId() + "b"
+
+		_, err := ss.Post().Save(&o1)
+		require.Nil(t, err, "couldn't save item")
+
+		_, err = ss.Post().Save(&o1)
+		require.NotNil(t, err, "shouldn't be able to update from save")
+	})
+
+	t.Run("Update reply should update the UpdateAt of the root post", func(t *testing.T) {
+		rootPost := model.Post{}
+		rootPost.ChannelId = model.NewId()
+		rootPost.UserId = model.NewId()
+		rootPost.Message = "zz" + model.NewId() + "b"
+
+		_, err := ss.Post().Save(&rootPost)
+		require.Nil(t, err)
+
+		replyPost := model.Post{}
+		replyPost.ChannelId = rootPost.ChannelId
+		replyPost.UserId = model.NewId()
+		replyPost.Message = "zz" + model.NewId() + "b"
+		replyPost.RootId = rootPost.Id
+
+		_, err = ss.Post().Save(&replyPost)
+		require.Nil(t, err)
+
+		rrootPost, err := ss.Post().GetSingle(rootPost.Id)
+		require.Nil(t, err)
+		assert.Greater(t, rrootPost.UpdateAt, rootPost.UpdateAt)
+	})
+
+	t.Run("Create a post should update the channel LastPostAt and the total messages count by one", func(t *testing.T) {
+		channel := model.Channel{}
+		channel.Name = "zz" + model.NewId() + "b"
+		channel.DisplayName = "zz" + model.NewId() + "b"
+		channel.Type = model.CHANNEL_OPEN
+
+		_, err := ss.Channel().Save(&channel, 100)
+		require.Nil(t, err)
+
+		post := model.Post{}
+		post.ChannelId = channel.Id
+		post.UserId = model.NewId()
+		post.Message = "zz" + model.NewId() + "b"
+
+		_, err = ss.Post().Save(&post)
+		require.Nil(t, err)
+
+		rchannel, err := ss.Channel().Get(channel.Id, false)
+		require.Nil(t, err)
+		assert.Greater(t, rchannel.LastPostAt, channel.LastPostAt)
+		assert.Equal(t, int64(1), rchannel.TotalMsgCount)
+
+		post = model.Post{}
+		post.ChannelId = channel.Id
+		post.UserId = model.NewId()
+		post.Message = "zz" + model.NewId() + "b"
+		post.CreateAt = 5
+
+		_, err = ss.Post().Save(&post)
+		require.Nil(t, err)
+
+		rchannel2, err := ss.Channel().Get(channel.Id, false)
+		require.Nil(t, err)
+		assert.Equal(t, rchannel.LastPostAt, rchannel2.LastPostAt)
+		assert.Equal(t, int64(2), rchannel2.TotalMsgCount)
+
+		post = model.Post{}
+		post.ChannelId = channel.Id
+		post.UserId = model.NewId()
+		post.Message = "zz" + model.NewId() + "b"
+
+		_, err = ss.Post().Save(&post)
+		require.Nil(t, err)
+
+		rchannel3, err := ss.Channel().Get(channel.Id, false)
+		require.Nil(t, err)
+		assert.Greater(t, rchannel3.LastPostAt, rchannel2.LastPostAt)
+		assert.Equal(t, int64(3), rchannel3.TotalMsgCount)
+	})
+}
+
+func testPostStoreSaveMultiple(t *testing.T, ss store.Store) {
+	p1 := model.Post{}
+	p1.ChannelId = model.NewId()
+	p1.UserId = model.NewId()
+	p1.Message = "zz" + model.NewId() + "b"
+
+	p2 := model.Post{}
+	p2.ChannelId = model.NewId()
+	p2.UserId = model.NewId()
+	p2.Message = "zz" + model.NewId() + "b"
+
+	p3 := model.Post{}
+	p3.ChannelId = model.NewId()
+	p3.UserId = model.NewId()
+	p3.Message = "zz" + model.NewId() + "b"
+
+	p4 := model.Post{}
+	p4.ChannelId = model.NewId()
+	p4.UserId = model.NewId()
+	p4.Message = "zz" + model.NewId() + "b"
+
+	t.Run("Save correctly a new set of posts", func(t *testing.T) {
+		newPosts, err := ss.Post().SaveMultiple([]*model.Post{&p1, &p2, &p3})
+		require.Nil(t, err)
+		for _, post := range newPosts {
+			storedPost, err := ss.Post().GetSingle(post.Id)
+			assert.Nil(t, err)
+			assert.Equal(t, post.ChannelId, storedPost.ChannelId)
+			assert.Equal(t, post.Message, storedPost.Message)
+			assert.Equal(t, post.UserId, storedPost.UserId)
+		}
+	})
+
+	t.Run("Try to save mixed, already saved and not saved posts", func(t *testing.T) {
+		newPosts, err := ss.Post().SaveMultiple([]*model.Post{&p4, &p3})
+		require.NotNil(t, err)
+		require.Nil(t, newPosts)
+		storedPost, err := ss.Post().GetSingle(p3.Id)
+		assert.Nil(t, err)
+		assert.Equal(t, p3.ChannelId, storedPost.ChannelId)
+		assert.Equal(t, p3.Message, storedPost.Message)
+		assert.Equal(t, p3.UserId, storedPost.UserId)
+
+		storedPost, err = ss.Post().GetSingle(p4.Id)
+		assert.NotNil(t, err)
+		assert.Nil(t, storedPost)
+	})
+
+	t.Run("Update reply should update the UpdateAt of the root post", func(t *testing.T) {
+		rootPost := model.Post{}
+		rootPost.ChannelId = model.NewId()
+		rootPost.UserId = model.NewId()
+		rootPost.Message = "zz" + model.NewId() + "b"
+
+		replyPost := model.Post{}
+		replyPost.ChannelId = rootPost.ChannelId
+		replyPost.UserId = model.NewId()
+		replyPost.Message = "zz" + model.NewId() + "b"
+		replyPost.RootId = rootPost.Id
+
+		_, err := ss.Post().SaveMultiple([]*model.Post{&rootPost, &replyPost})
+		require.Nil(t, err)
+
+		rrootPost, err := ss.Post().GetSingle(rootPost.Id)
+		require.Nil(t, err)
+		assert.Equal(t, rrootPost.UpdateAt, rootPost.UpdateAt)
+
+		replyPost2 := model.Post{}
+		replyPost2.ChannelId = rootPost.ChannelId
+		replyPost2.UserId = model.NewId()
+		replyPost2.Message = "zz" + model.NewId() + "b"
+		replyPost2.RootId = rootPost.Id
+
+		replyPost3 := model.Post{}
+		replyPost3.ChannelId = rootPost.ChannelId
+		replyPost3.UserId = model.NewId()
+		replyPost3.Message = "zz" + model.NewId() + "b"
+		replyPost3.RootId = rootPost.Id
+
+		_, err = ss.Post().SaveMultiple([]*model.Post{&replyPost2, &replyPost3})
+		require.Nil(t, err)
+
+		rrootPost2, err := ss.Post().GetSingle(rootPost.Id)
+		require.Nil(t, err)
+		assert.Greater(t, rrootPost2.UpdateAt, rrootPost.UpdateAt)
+	})
+
+	t.Run("Create a post should update the channel LastPostAt and the total messages count by one", func(t *testing.T) {
+		channel := model.Channel{}
+		channel.Name = "zz" + model.NewId() + "b"
+		channel.DisplayName = "zz" + model.NewId() + "b"
+		channel.Type = model.CHANNEL_OPEN
+
+		_, err := ss.Channel().Save(&channel, 100)
+		require.Nil(t, err)
+
+		post1 := model.Post{}
+		post1.ChannelId = channel.Id
+		post1.UserId = model.NewId()
+		post1.Message = "zz" + model.NewId() + "b"
+
+		post2 := model.Post{}
+		post2.ChannelId = channel.Id
+		post2.UserId = model.NewId()
+		post2.Message = "zz" + model.NewId() + "b"
+		post2.CreateAt = 5
+
+		post3 := model.Post{}
+		post3.ChannelId = channel.Id
+		post3.UserId = model.NewId()
+		post3.Message = "zz" + model.NewId() + "b"
+
+		_, err = ss.Post().SaveMultiple([]*model.Post{&post1, &post2, &post3})
+		require.Nil(t, err)
+
+		rchannel, err := ss.Channel().Get(channel.Id, false)
+		require.Nil(t, err)
+		assert.Greater(t, rchannel.LastPostAt, channel.LastPostAt)
+		assert.Equal(t, int64(3), rchannel.TotalMsgCount)
+	})
 }
 
 func testPostStoreSaveChannelMsgCounts(t *testing.T, ss store.Store) {
@@ -2005,6 +2214,136 @@ func testPostStoreGetPostsCreatedAt(t *testing.T, ss store.Store) {
 	assert.Equal(t, 2, len(r1))
 }
 
+func testPostStoreOverwriteMultiple(t *testing.T, ss store.Store) {
+	o1 := &model.Post{}
+	o1.ChannelId = model.NewId()
+	o1.UserId = model.NewId()
+	o1.Message = "zz" + model.NewId() + "AAAAAAAAAAA"
+	o1, err := ss.Post().Save(o1)
+	require.Nil(t, err)
+
+	o2 := &model.Post{}
+	o2.ChannelId = o1.ChannelId
+	o2.UserId = model.NewId()
+	o2.Message = "zz" + model.NewId() + "CCCCCCCCC"
+	o2.ParentId = o1.Id
+	o2.RootId = o1.Id
+	o2, err = ss.Post().Save(o2)
+	require.Nil(t, err)
+
+	o3 := &model.Post{}
+	o3.ChannelId = o1.ChannelId
+	o3.UserId = model.NewId()
+	o3.Message = "zz" + model.NewId() + "QQQQQQQQQQ"
+	o3, err = ss.Post().Save(o3)
+	require.Nil(t, err)
+
+	o4, err := ss.Post().Save(&model.Post{
+		ChannelId: model.NewId(),
+		UserId:    model.NewId(),
+		Message:   model.NewId(),
+		Filenames: []string{"test"},
+	})
+	require.Nil(t, err)
+
+	o5, err := ss.Post().Save(&model.Post{
+		ChannelId: model.NewId(),
+		UserId:    model.NewId(),
+		Message:   model.NewId(),
+		Filenames: []string{"test2", "test3"},
+	})
+	require.Nil(t, err)
+
+	r1, err := ss.Post().Get(o1.Id, false)
+	require.Nil(t, err)
+	ro1 := r1.Posts[o1.Id]
+
+	r2, err := ss.Post().Get(o2.Id, false)
+	require.Nil(t, err)
+	ro2 := r2.Posts[o2.Id]
+
+	r3, err := ss.Post().Get(o3.Id, false)
+	require.Nil(t, err)
+	ro3 := r3.Posts[o3.Id]
+
+	r4, err := ss.Post().Get(o4.Id, false)
+	require.Nil(t, err)
+	ro4 := r4.Posts[o4.Id]
+
+	r5, err := ss.Post().Get(o5.Id, false)
+	require.Nil(t, err)
+	ro5 := r5.Posts[o5.Id]
+
+	require.Equal(t, ro1.Message, o1.Message, "Failed to save/get")
+	require.Equal(t, ro2.Message, o2.Message, "Failed to save/get")
+	require.Equal(t, ro3.Message, o3.Message, "Failed to save/get")
+	require.Equal(t, ro4.Message, o4.Message, "Failed to save/get")
+	require.Equal(t, ro4.Filenames, o4.Filenames, "Failed to save/get")
+	require.Equal(t, ro5.Message, o5.Message, "Failed to save/get")
+	require.Equal(t, ro5.Filenames, o5.Filenames, "Failed to save/get")
+
+	t.Run("overwrite changing message", func(t *testing.T) {
+		o1a := &model.Post{}
+		*o1a = *ro1
+		o1a.Message = ro1.Message + "BBBBBBBBBB"
+
+		o2a := &model.Post{}
+		*o2a = *ro2
+		o2a.Message = ro2.Message + "DDDDDDD"
+
+		o3a := &model.Post{}
+		*o3a = *ro3
+		o3a.Message = ro3.Message + "WWWWWWW"
+
+		_, err = ss.Post().OverwriteMultiple([]*model.Post{o1a, o2a, o3a})
+		require.Nil(t, err)
+
+		r1, err = ss.Post().Get(o1.Id, false)
+		require.Nil(t, err)
+		ro1a := r1.Posts[o1.Id]
+
+		r2, err = ss.Post().Get(o1.Id, false)
+		require.Nil(t, err)
+		ro2a := r2.Posts[o2.Id]
+
+		r3, err = ss.Post().Get(o3.Id, false)
+		require.Nil(t, err)
+		ro3a := r3.Posts[o3.Id]
+
+		assert.Equal(t, ro1a.Message, o1a.Message, "Failed to overwrite/get")
+		assert.Equal(t, ro2a.Message, o2a.Message, "Failed to overwrite/get")
+		assert.Equal(t, ro3a.Message, o3a.Message, "Failed to overwrite/get")
+	})
+
+	t.Run("overwrite clearing filenames", func(t *testing.T) {
+		o4a := &model.Post{}
+		*o4a = *ro4
+		o4a.Filenames = []string{}
+		o4a.FileIds = []string{model.NewId()}
+
+		o5a := &model.Post{}
+		*o5a = *ro5
+		o5a.Filenames = []string{}
+		o5a.FileIds = []string{}
+
+		_, err = ss.Post().OverwriteMultiple([]*model.Post{o4a, o5a})
+		require.Nil(t, err)
+
+		r4, err = ss.Post().Get(o4.Id, false)
+		require.Nil(t, err)
+		ro4a := r4.Posts[o4.Id]
+
+		r5, err = ss.Post().Get(o5.Id, false)
+		require.Nil(t, err)
+		ro5a := r5.Posts[o5.Id]
+
+		require.Empty(t, ro4a.Filenames, "Failed to clear Filenames")
+		require.Len(t, ro4a.FileIds, 1, "Failed to set FileIds")
+		require.Empty(t, ro5a.Filenames, "Failed to clear Filenames")
+		require.Empty(t, ro5a.FileIds, "Failed to set FileIds")
+	})
+}
+
 func testPostStoreOverwrite(t *testing.T, ss store.Store) {
 	o1 := &model.Post{}
 	o1.ChannelId = model.NewId()
@@ -2029,56 +2368,6 @@ func testPostStoreOverwrite(t *testing.T, ss store.Store) {
 	o3, err = ss.Post().Save(o3)
 	require.Nil(t, err)
 
-	r1, err := ss.Post().Get(o1.Id, false)
-	require.Nil(t, err)
-	ro1 := r1.Posts[o1.Id]
-
-	r2, err := ss.Post().Get(o1.Id, false)
-	require.Nil(t, err)
-	ro2 := r2.Posts[o2.Id]
-
-	r3, err := ss.Post().Get(o3.Id, false)
-	require.Nil(t, err)
-	ro3 := r3.Posts[o3.Id]
-
-	require.Equal(t, ro1.Message, o1.Message, "Failed to save/get")
-
-	o1a := &model.Post{}
-	*o1a = *ro1
-	o1a.Message = ro1.Message + "BBBBBBBBBB"
-	_, err = ss.Post().Overwrite(o1a)
-	require.Nil(t, err)
-
-	r1, err = ss.Post().Get(o1.Id, false)
-	require.Nil(t, err)
-	ro1a := r1.Posts[o1.Id]
-
-	require.Equal(t, ro1a.Message, o1a.Message, "Failed to overwrite/get")
-
-	o2a := &model.Post{}
-	*o2a = *ro2
-	o2a.Message = ro2.Message + "DDDDDDD"
-	_, err = ss.Post().Overwrite(o2a)
-	require.Nil(t, err)
-
-	r2, err = ss.Post().Get(o1.Id, false)
-	require.Nil(t, err)
-	ro2a := r2.Posts[o2.Id]
-
-	require.Equal(t, ro2a.Message, o2a.Message, "Failed to overwrite/get")
-
-	o3a := &model.Post{}
-	*o3a = *ro3
-	o3a.Message = ro3.Message + "WWWWWWW"
-	_, err = ss.Post().Overwrite(o3a)
-	require.Nil(t, err)
-
-	r3, err = ss.Post().Get(o3.Id, false)
-	require.Nil(t, err)
-	ro3a := r3.Posts[o3.Id]
-
-	require.Equal(t, ro3a.Message, o3a.Message, "Failed to overwrite/get")
-
 	o4, err := ss.Post().Save(&model.Post{
 		ChannelId: model.NewId(),
 		UserId:    model.NewId(),
@@ -2087,23 +2376,78 @@ func testPostStoreOverwrite(t *testing.T, ss store.Store) {
 	})
 	require.Nil(t, err)
 
+	r1, err := ss.Post().Get(o1.Id, false)
+	require.Nil(t, err)
+	ro1 := r1.Posts[o1.Id]
+
+	r2, err := ss.Post().Get(o2.Id, false)
+	require.Nil(t, err)
+	ro2 := r2.Posts[o2.Id]
+
+	r3, err := ss.Post().Get(o3.Id, false)
+	require.Nil(t, err)
+	ro3 := r3.Posts[o3.Id]
+
 	r4, err := ss.Post().Get(o4.Id, false)
 	require.Nil(t, err)
 	ro4 := r4.Posts[o4.Id]
 
-	o4a := &model.Post{}
-	*o4a = *ro4
-	o4a.Filenames = []string{}
-	o4a.FileIds = []string{model.NewId()}
-	_, err = ss.Post().Overwrite(o4a)
-	require.Nil(t, err)
+	require.Equal(t, ro1.Message, o1.Message, "Failed to save/get")
+	require.Equal(t, ro2.Message, o2.Message, "Failed to save/get")
+	require.Equal(t, ro3.Message, o3.Message, "Failed to save/get")
+	require.Equal(t, ro4.Message, o4.Message, "Failed to save/get")
 
-	r4, err = ss.Post().Get(o4.Id, false)
-	require.Nil(t, err)
+	t.Run("overwrite changing message", func(t *testing.T) {
+		o1a := &model.Post{}
+		*o1a = *ro1
+		o1a.Message = ro1.Message + "BBBBBBBBBB"
+		_, err = ss.Post().Overwrite(o1a)
+		require.Nil(t, err)
 
-	ro4a := r4.Posts[o4.Id]
-	require.Empty(t, ro4a.Filenames, "Failed to clear Filenames")
-	require.Len(t, ro4a.FileIds, 1, "Failed to set FileIds")
+		o2a := &model.Post{}
+		*o2a = *ro2
+		o2a.Message = ro2.Message + "DDDDDDD"
+		_, err = ss.Post().Overwrite(o2a)
+		require.Nil(t, err)
+
+		o3a := &model.Post{}
+		*o3a = *ro3
+		o3a.Message = ro3.Message + "WWWWWWW"
+		_, err = ss.Post().Overwrite(o3a)
+		require.Nil(t, err)
+
+		r1, err = ss.Post().Get(o1.Id, false)
+		require.Nil(t, err)
+		ro1a := r1.Posts[o1.Id]
+
+		r2, err = ss.Post().Get(o1.Id, false)
+		require.Nil(t, err)
+		ro2a := r2.Posts[o2.Id]
+
+		r3, err = ss.Post().Get(o3.Id, false)
+		require.Nil(t, err)
+		ro3a := r3.Posts[o3.Id]
+
+		assert.Equal(t, ro1a.Message, o1a.Message, "Failed to overwrite/get")
+		assert.Equal(t, ro2a.Message, o2a.Message, "Failed to overwrite/get")
+		assert.Equal(t, ro3a.Message, o3a.Message, "Failed to overwrite/get")
+	})
+
+	t.Run("overwrite clearing filenames", func(t *testing.T) {
+		o4a := &model.Post{}
+		*o4a = *ro4
+		o4a.Filenames = []string{}
+		o4a.FileIds = []string{model.NewId()}
+		_, err = ss.Post().Overwrite(o4a)
+		require.Nil(t, err)
+
+		r4, err = ss.Post().Get(o4.Id, false)
+		require.Nil(t, err)
+
+		ro4a := r4.Posts[o4.Id]
+		require.Empty(t, ro4a.Filenames, "Failed to clear Filenames")
+		require.Len(t, ro4a.FileIds, 1, "Failed to set FileIds")
+	})
 }
 
 func testPostStoreGetPostsByIds(t *testing.T, ss store.Store) {

store/storetest/team_store.go

@@ -30,6 +30,7 @@ func TestTeamStore(t *testing.T, ss store.Store) {
 	t.Run("Update", func(t *testing.T) { testTeamStoreUpdate(t, ss) })
 	t.Run("Get", func(t *testing.T) { testTeamStoreGet(t, ss) })
 	t.Run("GetByName", func(t *testing.T) { testTeamStoreGetByName(t, ss) })
+	t.Run("GetByNames", func(t *testing.T) { testTeamStoreGetByNames(t, ss) })
 	t.Run("SearchAll", func(t *testing.T) { testTeamStoreSearchAll(t, ss) })
 	t.Run("SearchOpen", func(t *testing.T) { testTeamStoreSearchOpen(t, ss) })
 	t.Run("SearchPrivate", func(t *testing.T) { testTeamStoreSearchPrivate(t, ss) })
@@ -122,6 +123,59 @@ func testTeamStoreGet(t *testing.T, ss store.Store) {
 	require.NotNil(t, err, "Missing id should have failed")
 }
 
+func testTeamStoreGetByNames(t *testing.T, ss store.Store) {
+	o1 := model.Team{}
+	o1.DisplayName = "DisplayName"
+	o1.Name = "z-z-z" + model.NewId() + "b"
+	o1.Email = MakeEmail()
+	o1.Type = model.TEAM_OPEN
+
+	_, err := ss.Team().Save(&o1)
+	require.Nil(t, err)
+
+	o2 := model.Team{}
+	o2.DisplayName = "DisplayName2"
+	o2.Name = "z-z-z" + model.NewId() + "b"
+	o2.Email = MakeEmail()
+	o2.Type = model.TEAM_OPEN
+
+	_, err = ss.Team().Save(&o2)
+	require.Nil(t, err)
+
+	t.Run("Get empty list", func(t *testing.T) {
+		var teams []*model.Team
+		teams, err = ss.Team().GetByNames([]string{})
+		require.Nil(t, err)
+		require.Empty(t, teams)
+	})
+
+	t.Run("Get existing teams", func(t *testing.T) {
+		var teams []*model.Team
+		teams, err = ss.Team().GetByNames([]string{o1.Name, o2.Name})
+		require.Nil(t, err)
+		teamsIds := []string{}
+		for _, team := range teams {
+			teamsIds = append(teamsIds, team.Id)
+		}
+		assert.Contains(t, teamsIds, o1.Id, "invalid returned team")
+		assert.Contains(t, teamsIds, o2.Id, "invalid returned team")
+	})
+
+	t.Run("Get existing team and one invalid team name", func(t *testing.T) {
+		_, err = ss.Team().GetByNames([]string{o1.Name, ""})
+		require.NotNil(t, err)
+	})
+
+	t.Run("Get existing team and not existing team", func(t *testing.T) {
+		_, err = ss.Team().GetByNames([]string{o1.Name, "not-existing-team-name"})
+		require.NotNil(t, err)
+	})
+	t.Run("Get not existing teams", func(t *testing.T) {
+		_, err = ss.Team().GetByNames([]string{"not-existing-team-name", "not-existing-team-name-2"})
+		require.NotNil(t, err)
+	})
+}
+
 func testTeamStoreGetByName(t *testing.T, ss store.Store) {
 	o1 := model.Team{}
 	o1.DisplayName = "DisplayName"
@@ -132,12 +186,22 @@ func testTeamStoreGetByName(t *testing.T, ss store.Store) {
 	_, err := ss.Team().Save(&o1)
 	require.Nil(t, err)
 
-	team, err := ss.Team().GetByName(o1.Name)
-	require.Nil(t, err)
-	require.Equal(t, *team, o1, "invalid returned team")
+	t.Run("Get existing team", func(t *testing.T) {
+		var team *model.Team
+		team, err = ss.Team().GetByName(o1.Name)
+		require.Nil(t, err)
+		require.Equal(t, *team, o1, "invalid returned team")
+	})
 
-	_, err = ss.Team().GetByName("")
-	require.NotNil(t, err, "Missing id should have failed")
+	t.Run("Get invalid team name", func(t *testing.T) {
+		_, err = ss.Team().GetByName("")
+		require.NotNil(t, err, "Missing id should have failed")
+	})
+
+	t.Run("Get not existing team", func(t *testing.T) {
+		_, err = ss.Team().GetByName("not-existing-team-name")
+		require.NotNil(t, err, "Missing id should have failed")
+	})
 }
 
 func testTeamStoreSearchAll(t *testing.T, ss store.Store) {

store/timer_layer.go

@@ -4412,6 +4412,22 @@ func (s *TimerLayerPostStore) Save(post *model.Post) (*model.Post, *model.AppErr
 	return resultVar0, resultVar1
 }
 
+func (s *TimerLayerPostStore) SaveMultiple(posts []*model.Post) ([]*model.Post, *model.AppError) {
+	start := timemodule.Now()
+
+	resultVar0, resultVar1 := s.PostStore.SaveMultiple(posts)
+
+	elapsed := float64(timemodule.Since(start)) / float64(timemodule.Second)
+	if s.Root.Metrics != nil {
+		success := "false"
+		if resultVar1 == nil {
+			success = "true"
+		}
+		s.Root.Metrics.ObserveStoreMethodDuration("PostStore.SaveMultiple", success, elapsed)
+	}
+	return resultVar0, resultVar1
+}
+
 func (s *TimerLayerPostStore) Search(teamId string, userId string, params *model.SearchParams) (*model.PostList, *model.AppError) {
 	start := timemodule.Now()