The log area of a database instance is subdivided into logical log segments. A log segment contains log entries. During log backup, the database system backs up each log segments to its own version file.
You configure the size of the log segment with the general database parameter LOG_SEGMENT_SIZE. It is unrelated to the size of the individual log volumes, but may not exceed the total of all log volumes. Select the size in such a way as to ensure that enough space remains in the log area when a log segment is being backed up to receive any new redo log entries that are written during the backup.
User Defined Value |
Log Segment Size Used by the System |
Log segment size not defined (LOG_SEGMENT_SIZE = 0) |
One-third of the total log area |
The log segment size in pages is smaller than or the same as 50% of the total log area. |
The value defined for LOG_SEGMENT_SIZE |
The log segment size > 50% of the total log area. |
50% of the log area |
See also:
Concepts of the Database System