diff --git a/store/sqlstore/upgrade.go b/store/sqlstore/upgrade.go
index 73830032c6..88011feb4b 100644
--- a/store/sqlstore/upgrade.go
+++ b/store/sqlstore/upgrade.go
@@ -521,6 +521,14 @@ func UpgradeDatabaseToVersion56(sqlStore SqlStore) {
 
 	// migrating user's accepted terms of service data into the new table
 	sqlStore.GetMaster().Exec("INSERT INTO UserTermsOfService SELECT Id, AcceptedTermsOfServiceId as TermsOfServiceId, :CreateAt FROM Users WHERE AcceptedTermsOfServiceId != \"\" AND AcceptedTermsOfServiceId IS NOT NULL", map[string]interface{}{"CreateAt": model.GetMillis()})
+
+	if sqlStore.DriverName() == model.DATABASE_DRIVER_POSTGRES {
+		sqlStore.RemoveIndexIfExists("idx_users_email_lower", "lower(Email)")
+		sqlStore.RemoveIndexIfExists("idx_users_username_lower", "lower(Username)")
+		sqlStore.RemoveIndexIfExists("idx_users_nickname_lower", "lower(Nickname)")
+		sqlStore.RemoveIndexIfExists("idx_users_firstname_lower", "lower(FirstName)")
+		sqlStore.RemoveIndexIfExists("idx_users_lastname_lower", "lower(LastName)")
+	}
 	//saveSchemaVersion(sqlStore, VERSION_5_6_0)
 	//}
 }
diff --git a/store/sqlstore/user_store.go b/store/sqlstore/user_store.go
index 8136d4ac4f..02092d2240 100644
--- a/store/sqlstore/user_store.go
+++ b/store/sqlstore/user_store.go
@@ -94,11 +94,11 @@ func (us SqlUserStore) CreateIndexesIfNotExists() {
 	us.CreateIndexIfNotExists("idx_users_delete_at", "Users", "DeleteAt")
 
 	if us.DriverName() == model.DATABASE_DRIVER_POSTGRES {
-		us.CreateIndexIfNotExists("idx_users_email_lower", "Users", "lower(Email)")
-		us.CreateIndexIfNotExists("idx_users_username_lower", "Users", "lower(Username)")
-		us.CreateIndexIfNotExists("idx_users_nickname_lower", "Users", "lower(Nickname)")
-		us.CreateIndexIfNotExists("idx_users_firstname_lower", "Users", "lower(FirstName)")
-		us.CreateIndexIfNotExists("idx_users_lastname_lower", "Users", "lower(LastName)")
+		us.CreateIndexIfNotExists("idx_users_email_lower_textpattern", "Users", "lower(Email) text_pattern_ops")
+		us.CreateIndexIfNotExists("idx_users_username_lower_textpattern", "Users", "lower(Username) text_pattern_ops")
+		us.CreateIndexIfNotExists("idx_users_nickname_lower_textpattern", "Users", "lower(Nickname) text_pattern_ops")
+		us.CreateIndexIfNotExists("idx_users_firstname_lower_textpattern", "Users", "lower(FirstName) text_pattern_ops")
+		us.CreateIndexIfNotExists("idx_users_lastname_lower_textpattern", "Users", "lower(LastName) text_pattern_ops")
 	}
 
 	us.CreateFullTextIndexIfNotExists("idx_users_all_txt", "Users", strings.Join(USER_SEARCH_TYPE_ALL, ", "))