1. The lock request or an implicit lock conflicts with the locks of another user. The maximum waiting time for being granted the lock has elapsed (database parameter REQUEST_TIMEOUT).
2. The database instance could not be stopped within a certain period of time because transactions with SQL statements for data modification are still open.
3. In some cases, the error message contains a more detailed description of the error. The lock request can be reissued. To avoid possible deadlock situations, it is advisable to roll back the transaction with a ROLLBACK statement to avoid possible deadlock situations.
4. Use the QUICK option to omit stopping or forcing the database instance to shut down.