Prior to Ingres II 2.5, when the DBMS fetched a row for a cursor mode update, it would acquire an exclusive lock. In serializable mode, this lock would be held until the end of transaction, even when the row was not updated. In this release, the Ingres DBMS acquires an update mode lock for the row that is a candidate for update. If the row is actually updated, the update mode lock is converted to logical exclusive lock; otherwise, it is converted down to shared lock or released, depending on the current isolation level. Update mode locking is now the default for cursor updates.