[MM-26397] Take query size and order into account for Bleve (#14882)

* [MM-26397] Take query size and order into account for Bleve

* Add a test to check post search pagination

* Add tests for checking limit when searching users

* Make pagination an independent test to discriminate DB engines

services/searchengine/bleveengine/search.go

@@ -196,7 +196,8 @@ func (b *BleveEngine) SearchPosts(channels *model.ChannelList, searchParams []*m
 		query.AddMustNot(notFilters...)
 	}
 
-	search := bleve.NewSearchRequest(query)
+	search := bleve.NewSearchRequestOptions(query, perPage, page*perPage, false)
+	search.SortBy([]string{"-CreateAt"})
 	results, err := b.PostIndex.Search(search)
 	if err != nil {
 		return nil, nil, model.NewAppError("Bleveengine.SearchPosts", "bleveengine.search_posts.error", nil, err.Error(), http.StatusInternalServerError)
@@ -311,6 +312,7 @@ func (b *BleveEngine) SearchChannels(teamId, term string) ([]string, *model.AppE
 	}
 
 	query := bleve.NewSearchRequest(bleve.NewConjunctionQuery(queries...))
+	query.Size = model.CHANNEL_SEARCH_DEFAULT_LIMIT
 	results, err := b.ChannelIndex.Search(query)
 	if err != nil {
 		return nil, model.NewAppError("Bleveengine.SearchChannels", "bleveengine.search_channels.error", nil, err.Error(), http.StatusInternalServerError)
@@ -368,7 +370,9 @@ func (b *BleveEngine) SearchUsersInChannel(teamId, channelId string, restrictedT
 
 	query := bleve.NewConjunctionQuery(queries...)
 
-	uchan, err := b.UserIndex.Search(bleve.NewSearchRequest(query))
+	uchanSearch := bleve.NewSearchRequest(query)
+	uchanSearch.Size = options.Limit
+	uchan, err := b.UserIndex.Search(uchanSearch)
 	if err != nil {
 		return nil, nil, model.NewAppError("Bleveengine.SearchUsersInChannel", "bleveengine.search_users_in_channel.uchan.error", nil, err.Error(), http.StatusInternalServerError)
 	}
@@ -403,7 +407,9 @@ func (b *BleveEngine) SearchUsersInChannel(teamId, channelId string, restrictedT
 		boolQ.AddMust(restrictedChannelsQ)
 	}
 
-	nuchan, err := b.UserIndex.Search(bleve.NewSearchRequest(boolQ))
+	nuchanSearch := bleve.NewSearchRequest(boolQ)
+	nuchanSearch.Size = options.Limit
+	nuchan, err := b.UserIndex.Search(nuchanSearch)
 	if err != nil {
 		return nil, nil, model.NewAppError("Bleveengine.SearchUsersInChannel", "bleveengine.search_users_in_channel.nuchan.error", nil, err.Error(), http.StatusInternalServerError)
 	}
@@ -465,7 +471,7 @@ func (b *BleveEngine) SearchUsersInTeam(teamId string, restrictedToChannels []st
 	}
 
 	search := bleve.NewSearchRequest(rootQ)
-
+	search.Size = options.Limit
 	results, err := b.UserIndex.Search(search)
 	if err != nil {
 		return nil, model.NewAppError("Bleveengine.SearchUsersInTeam", "bleveengine.search_users_in_team.error", nil, err.Error(), http.StatusInternalServerError)