postgres use specific full text idx (#11022)

store/sqlstore/channel_store.go

@@ -2218,7 +2218,7 @@ func (s SqlChannelStore) buildFulltextClause(term string, searchColumns string)
 
 		fulltextTerm = strings.Join(splitTerm, " ")
 
-		fulltextClause = fmt.Sprintf("((%s) @@ to_tsquery(:FulltextTerm))", convertMySQLFullTextColumnsToPostgres(searchColumns))
+		fulltextClause = fmt.Sprintf("((to_tsvector('english', %s)) @@ to_tsquery(:FulltextTerm))", convertMySQLFullTextColumnsToPostgres(searchColumns))
 	} else if s.DriverName() == model.DATABASE_DRIVER_MYSQL {
 		splitTerm := strings.Fields(fulltextTerm)
 		for i, t := range strings.Fields(fulltextTerm) {

store/sqlstore/post_store.go

@@ -893,7 +893,7 @@ func (s *SqlPostStore) Search(teamId string, userId string, params *model.Search
 				terms = strings.Join(strings.Fields(terms), " & ")
 			}
 
-			searchClause := fmt.Sprintf("AND %s @@  to_tsquery(:Terms)", searchType)
+			searchClause := fmt.Sprintf("AND to_tsvector('english', %s) @@  to_tsquery(:Terms)", searchType)
 			searchQuery = strings.Replace(searchQuery, "SEARCH_CLAUSE", searchClause, 1)
 		} else if s.DriverName() == model.DATABASE_DRIVER_MYSQL {
 			searchClause := fmt.Sprintf("AND MATCH (%s) AGAINST (:Terms IN BOOLEAN MODE)", searchType)