What Is the Logical Log?

To keep a history of transactions and database server changes since the time of the last storage-space backup, the database server generates log records. The database server stores the log records in the logical log, a circular file that is composed of three or more logical-log files. The log is called logical because the log records represent logical operations of the database server, as opposed to physical operations. At any time, the combination of a storage-space backup plus logical-log backup contains a complete copy of your database server data.

As the database server administrator, you must configure and manage the logical log. For example, if you do not back up the log files regularly, the logical log fills and the database server suspends processing.

These responsibilities include the following tasks:

• Choosing an appropriate location for the logical log

  See Location of Logical-Log Files.

• Monitoring the logical-log file status

  See Identification of Logical-Log Files.

• Allocating an appropriate amount of disk space for the logical log

  See Size of the Logical Log.

• Allocating additional log files whenever necessary

  See Allocating Log Files.

• Backing up the logical-log files to media

  See Backing Up Logical-Log Files and Freeing of Logical-Log Files.

• Managing logging of blobspaces and sbspaces

  See Logging Blobspaces and Simple Large Objects and Logging Sbspaces and Smart Large Objects.