Automatic Recovery After a System Failure or Shutdown

Each time you restart SAP ASE—for example, after a power failure, an operating system failure, or the use of the shutdown command—it automatically performs a set of recovery procedures on each database.

The recovery mechanism compares each database to its transaction log. If the log record for a particular change is more recent than the data page, the recovery mechanism reapplies the change from the transaction log. If a transaction was ongoing at the time of the failure, the recovery mechanism reverses all changes that were made by the transaction.

  1. Recovers master.
  2. Recovers sybsystemprocs.
  3. Recovers model.
  4. Creates tempdb (by copying model).
  5. Recovers sybsystemdb.
  6. Recovers sybsecurity.
  7. Recovers user databases, in order by sysdatabases.dbid, or according to the order specified by sp_dbrecovery_order.

Users can log in to SAP ASE as soon as the system databases have been recovered, but they cannot access other databases until they have been recovered.

The configuration variable print recovery information determines whether SAP ASE displays detailed messages about each transaction on the console screen during recovery. By default, these messages do not appear. To display messages, use:

sp_configure "print recovery information", 1
Parent topic: Developing a Backup and Recovery Plan